/**************************************************************************************************
"POLYMOST" code written by Ken Silverman
Ken Silverman's official web site: http://www.advsys.net/ken

Motivation:
When 3D Realms released the Duke Nukem 3D source code, I thought somebody would do a OpenGL or
Direct3D port. Well, after a few months passed, I saw no sign of somebody working on a true
hardware-accelerated port of Build, just people saying it wasn't possible. Eventually, I realized
the only way this was going to happen was for me to do it myself. First, I needed to port Build to
Windows. I could have done it myself, but instead I thought I'd ask my Australian buddy, Jonathon
Fowler, if he would upgrade his Windows port to my favorite compiler (MSVC) - which he did. Once
that was done, I was ready to start the "POLYMOST" project.

About:
This source file is basically a complete rewrite of the entire rendering part of the Build engine.
There are small pieces in ENGINE.C to activate this code, and other minor hacks in other source
files, but most of it is in here. If you're looking for polymost-related code in the other source
files, you should find most of them by searching for either "polymost" or "rendmode". Speaking of
rendmode, there are now 4 rendering modes in Build:

    rendmode 0: The original code I wrote from 1993-1997
    rendmode 1: Solid-color rendering: my debug code before I did texture mapping
    rendmode 2: Software rendering before I started the OpenGL code (Note: this is just a quick
                        hack to make testing easier - it's not optimized to my usual standards!)
    rendmode 3: The OpenGL code

The original Build engine did hidden surface removal by using a vertical span buffer on the tops
and bottoms of walls. This worked nice back in the day, but it it's not suitable for a polygon
engine. So I decided to write a brand new hidden surface removal algorithm - using the same idea
as the original Build - but one that worked with vectors instead of already rasterized data.

Brief history:
06/20/2000: I release Build Source code
04/01/2003: 3D Realms releases Duke Nukem 3D source code
10/04/2003: Jonathon Fowler gets his Windows port working in Visual C
10/04/2003: I start writing POLYMOST.BAS, a new hidden surface removal algorithm for Build that
                    works on a polygon level instead of spans.
10/16/2003: Ported POLYMOST.BAS to C inside JonoF KenBuild's ENGINE.C; later this code was split
                    out of ENGINE.C and put in this file, POLYMOST.C.
12/10/2003: Started OpenGL code for POLYMOST (rendmode 3)
12/23/2003: 1st public release
01/01/2004: 2nd public release: fixed stray lines, status bar, mirrors, sky, and lots of other bugs.

----------------------------------------------------------------------------------------------------

Todo list (in approximate chronological order):

High priority:
    *   BOTH: Do accurate software sorting/chopping for sprites: drawing in wrong order is bad :/
    *   BOTH: Fix hall of mirrors near "zenith". Call polymost_drawrooms twice?
    * OPENGL: drawmapview()

Low priority:
    * SOFT6D: Do back-face culling of sprites during up/down/tilt transformation (top of drawpoly)
    * SOFT6D: Fix depth shading: use saturation&LUT
    * SOFT6D: Optimize using hyperbolic mapping (similar to KUBE algo)
    * SOFT6D: Slab6-style voxel sprites. How to accelerate? :/
    * OPENGL: KENBUILD: Write flipping code for floor mirrors
    *   BOTH: KENBUILD: Parallaxing sky modes 1&2
    *   BOTH: Masked/1-way walls don't clip correctly to sectors of intersecting ceiling/floor slopes
    *   BOTH: Editart x-center is not working correctly with Duke's camera/turret sprites
    *   BOTH: Get rid of horizontal line above Duke full-screen status bar
    *   BOTH: Combine ceilings/floors into a single triangle strip (should lower poly count by 2x)
    *   BOTH: Optimize/clean up texture-map setup equations

**************************************************************************************************/


#ifdef USE_OPENGL

#include "compat.h"
#include "build.h"
#include "glbuild.h"
#include "mdsprite.h"
#include "pragmas.h"
#include "baselayer.h"
#include "osd.h"
#include "engine_priv.h"
#include "hightile.h"
#include "polymost.h"
#include "polymer.h"
#include "cache1d.h"
#include "kplib.h"
#include "texcache.h"

#ifndef _WIN32
extern int32_t filelength(int h); // kplib.c
#endif

extern char textfont[2048], smalltextfont[2048];

int32_t rendmode=0;
int32_t usemodels=1, usehightile=1;

#include <math.h> //<-important!
typedef struct { float x, cy[2], fy[2]; int32_t tag; int16_t n, p, ctag, ftag; } vsptyp;
#define VSPMAX 4096 //<- careful!
static vsptyp vsp[VSPMAX];
static int32_t gtag;

static double dxb1[MAXWALLSB], dxb2[MAXWALLSB];

#define SCISDIST 1.0 //1.0: Close plane clipping distance
// the following three are for the obsolete rendmodes 1 and 2:
#define USEZBUFFER 1 //1:use zbuffer (slow, nice sprite rendering), 0:no zbuffer (fast, bad sprite rendering)
#define LINTERPSIZ 4 //log2 of interpolation size. 4:pretty fast&acceptable quality, 0:best quality/slow!
#define DEPTHDEBUG 0 //1:render distance instead of texture, for debugging only!, 0:default

float shadescale = 1.0f;
int32_t shadescale_unbounded = 0;

int32_t r_usenewshading = 2;
int32_t r_usetileshades = 1;

static double gviewxrange, ghoriz;
double gyxscale, gxyaspect, ghalfx, grhalfxdown10, grhalfxdown10x;
double gcosang, gsinang, gcosang2, gsinang2;
double gchang, gshang, gctang, gstang, gvisibility;
float gtang = 0.0;
double guo, gux, guy; //Screen-based texture mapping parameters
double gvo, gvx, gvy;
double gdo, gdx, gdy;

static int32_t preview_mouseaim=0;  // when 1, displays a CROSSHAIR tsprite at the _real_ aimed position

#ifdef USE_OPENGL
static int32_t srepeat = 0, trepeat = 0;

int32_t glredbluemode = 0;
static int32_t lastglredbluemode = 0, redblueclearcnt = 0;

struct glfiltermodes glfiltermodes[NUMGLFILTERMODES] =
{
    {"GL_NEAREST",GL_NEAREST,GL_NEAREST},
    {"GL_LINEAR",GL_LINEAR,GL_LINEAR},
    {"GL_NEAREST_MIPMAP_NEAREST",GL_NEAREST_MIPMAP_NEAREST,GL_NEAREST},
    {"GL_LINEAR_MIPMAP_NEAREST",GL_LINEAR_MIPMAP_NEAREST,GL_LINEAR},
    {"GL_NEAREST_MIPMAP_LINEAR",GL_NEAREST_MIPMAP_LINEAR,GL_NEAREST},
    {"GL_LINEAR_MIPMAP_LINEAR",GL_LINEAR_MIPMAP_LINEAR,GL_LINEAR}
};

int32_t glanisotropy = 1;            // 0 = maximum supported by card
int32_t glusetexcompr = 1;
int32_t gltexfiltermode = 2; // GL_NEAREST_MIPMAP_NEAREST
int32_t glusetexcache = 2, glusememcache = 1;
int32_t glmultisample = 0, glnvmultisamplehint = 0;
int32_t gltexmaxsize = 0;      // 0 means autodetection on first run
int32_t gltexmiplevel = 0;		// discards this many mipmap levels
static int32_t lastglpolygonmode = 0; //FUK
int32_t glpolygonmode = 0;     // 0:GL_FILL,1:GL_LINE,2:GL_POINT //FUK
int32_t glwidescreen = 0;
int32_t glprojectionhacks = 1;
static GLuint polymosttext = 0;
int32_t glrendmode = REND_POLYMOST;

// This variable, and 'shadeforfullbrightpass' control the drawing of
// fullbright tiles.  Also see 'fullbrightloadingpass'.
static int32_t fullbrightdrawingpass = 0;

float curpolygonoffset;    // internal polygon offset stack for drawing flat sprites to avoid depth fighting

// Detail mapping cvar
int32_t r_detailmapping = 1;

// Glow mapping cvar
int32_t r_glowmapping = 1;

// Vertex Array model drawing cvar
int32_t r_vertexarrays = 1;

// Vertex Buffer Objects model drawing cvars
int32_t r_vbos = 1;
int32_t r_vbocount = 64;

// model animation smoothing cvar
int32_t r_animsmoothing = 1;

// fullbright cvar
int32_t r_fullbrights = 1;

// texture downsizing
int32_t r_downsize = 0;
int32_t r_downsizevar = -1;

// used for fogcalc
float fogresult, fogresult2, fogcol[4], fogtable[4*MAXPALOOKUPS];
#endif

char ptempbuf[MAXWALLSB<<1];

// polymost ART sky control
int32_t r_parallaxskyclamping = 1;
int32_t r_parallaxskypanning = 0;

#define MIN_CACHETIME_PRINT 10

static inline int32_t imod(int32_t a, int32_t b)
{
    if (a >= 0) return(a%b);
    return(((a+1)%b)+b-1);
}

void drawline2d(float x0, float y0, float x1, float y1, char col)
{
    float f, dx, dy, fxres, fyres;
    int32_t e, inc, x, y;
    uint32_t up16;

    dx = x1-x0; dy = y1-y0; if ((dx == 0) && (dy == 0)) return;
    fxres = (float)xdimen; fyres = (float)ydimen;
    if (x0 >= fxres) { if (x1 >= fxres) return; y0 += (fxres-x0)*dy/dx; x0 = fxres; }
    else if (x0 <      0) { if (x1 <      0) return; y0 += (0-x0)*dy/dx; x0 =     0; }
    if (x1 >= fxres) {                          y1 += (fxres-x1)*dy/dx; x1 = fxres; }
    else if (x1 <      0) {                          y1 += (0-x1)*dy/dx; x1 =     0; }
    if (y0 >= fyres) { if (y1 >= fyres) return; x0 += (fyres-y0)*dx/dy; y0 = fyres; }
    else if (y0 <      0) { if (y1 <      0) return; x0 += (0-y0)*dx/dy; y0 =     0; }
    if (y1 >= fyres) {                          x1 += (fyres-y1)*dx/dy; y1 = fyres; }
    else if (y1 <      0) {                          x1 += (0-y1)*dx/dy; y1 =     0; }

    if (fabs(dx) > fabs(dy))
    {
        if (x0 > x1) { f = x0; x0 = x1; x1 = f; f = y0; y0 = y1; y1 = f; }
        y = (int32_t)(y0*65536.f)+32768;
        inc = (int32_t)(dy/dx*65536.f+.5f);
        x = (int32_t)(x0+.5); if (x < 0) { y -= inc*x; x = 0; } //if for safety
        e = (int32_t)(x1+.5); if (e > xdimen) e = xdimen;       //if for safety
        up16 = (ydimen<<16);
        for (; x<e; x++,y+=inc) if ((uint32_t)y < up16) *(char *)(ylookup[y>>16]+x+frameoffset) = col;
    }
    else
    {
        if (y0 > y1) { f = x0; x0 = x1; x1 = f; f = y0; y0 = y1; y1 = f; }
        x = (int32_t)(x0*65536.f)+32768;
        inc = (int32_t)(dx/dy*65536.f+.5f);
        y = (int32_t)(y0+.5); if (y < 0) { x -= inc*y; y = 0; } //if for safety
        e = (int32_t)(y1+.5); if (e > ydimen) e = ydimen;       //if for safety
        up16 = (xdimen<<16);
        for (; y<e; y++,x+=inc) if ((uint32_t)x < up16) *(char *)(ylookup[y]+(x>>16)+frameoffset) = col;
    }
}

#ifdef USE_OPENGL
int32_t mdtims, omdtims;
float alphahackarray[MAXTILES];
int32_t drawingskybox = 0;
int32_t hicprecaching = 0;


static inline int32_t gltexmayhavealpha(int32_t dapicnum, int32_t dapalnum)
{
    const int32_t j = (dapicnum&(GLTEXCACHEADSIZ-1));
    pthtyp *pth;

    for (pth=texcache.list[j]; pth; pth=pth->next)
        if (pth->picnum == dapicnum && pth->palnum == dapalnum)
            return ((pth->flags&8) != 0);

    return 1;
}

void gltexinvalidate(int32_t dapicnum, int32_t dapalnum, int32_t dameth)
{
    const int32_t j = (dapicnum&(GLTEXCACHEADSIZ-1));
    pthtyp *pth;

    for (pth=texcache.list[j]; pth; pth=pth->next)
        if (pth->picnum == dapicnum && pth->palnum == dapalnum && (pth->flags & 1) == ((dameth&4)>>2))
        {
            pth->flags |= 128;
            if (pth->flags & 16)
                pth->ofb->flags |= 128;
        }
}

//Make all textures "dirty" so they reload, but not re-allocate
//This should be much faster than polymost_glreset()
//Use this for palette effects ... but not ones that change every frame!
void gltexinvalidatetype(int32_t type)
{
    int32_t j;
    pthtyp *pth;

    for (j=GLTEXCACHEADSIZ-1; j>=0; j--)
    {
        for (pth=texcache.list[j]; pth; pth=pth->next)
        {
            if (type == INVALIDATE_ALL || (type == INVALIDATE_ART && pth->hicr == NULL))
            {
                pth->flags |= 128;
                if (pth->flags & 16)
                    pth->ofb->flags |= 128;
            }
        }
    }

    if (type == INVALIDATE_ALL)
        clearskins();
#ifdef DEBUGGINGAIDS
    OSD_Printf("gltexinvalidateall()\n");
#endif
}

static void bind_2d_texture(GLuint texture)
{
    bglBindTexture(GL_TEXTURE_2D, texture);
    bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, glfiltermodes[gltexfiltermode].mag);
    bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, glfiltermodes[gltexfiltermode].min);
    if (glinfo.maxanisotropy > 1.0)
        bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, glanisotropy);
}

void gltexapplyprops(void)
{
    int32_t i;
    pthtyp *pth;

    if (getrendermode() == REND_CLASSIC)
        return;

    if (glinfo.maxanisotropy > 1.0)
    {
        if (glanisotropy <= 0 || glanisotropy > glinfo.maxanisotropy)
            glanisotropy = (int32_t)glinfo.maxanisotropy;
    }

    gltexfiltermode = clamp(gltexfiltermode, 0, NUMGLFILTERMODES-1);

    for (i=GLTEXCACHEADSIZ-1; i>=0; i--)
    {
        for (pth=texcache.list[i]; pth; pth=pth->next)
        {
            bind_2d_texture(pth->glpic);

            if (r_fullbrights && pth->flags & 16)
                bind_2d_texture(pth->ofb->glpic);
        }
    }

    {
        int32_t j;
        mdskinmap_t *sk;
        md2model_t *m;

        for (i=0; i<nextmodelid; i++)
        {
            m = (md2model_t *)models[i];
            if (m->mdnum < 2) continue;
            for (j=0; j<m->numskins*(HICEFFECTMASK+1); j++)
            {
                if (!m->texid[j]) continue;
                bind_2d_texture(m->texid[j]);
            }

            for (sk=m->skinmap; sk; sk=sk->next)
                for (j=0; j<(HICEFFECTMASK+1); j++)
                {
                    if (!sk->texid[j]) continue;
                    bind_2d_texture(sk->texid[j]);
                }
        }
    }
}

//--------------------------------------------------------------------------------------------------

float glox1, gloy1, glox2, gloy2;

//Use this for both initialization and uninitialization of OpenGL.
static int32_t gltexcacnum = -1;
extern void freevbos(void);

void polymost_glreset()
{
    int32_t i;
    pthtyp *pth, *next;

    for (i=MAXPALOOKUPS-1; i>=0; i--)
    {
        fogtable[i<<2] = palookupfog[i].r / 63.f;
        fogtable[(i<<2)+1] = palookupfog[i].g / 63.f;
        fogtable[(i<<2)+2] = palookupfog[i].b / 63.f;
        fogtable[(i<<2)+3] = 0;
    }

    //Reset if this is -1 (meaning 1st texture call ever), or > 0 (textures in memory)
    if (gltexcacnum < 0)
    {
        gltexcacnum = 0;

        //Hack for polymost_dorotatesprite calls before 1st polymost_drawrooms()
        gcosang = gcosang2 = ((double)16384)/262144.0;
        gsinang = gsinang2 = ((double)    0)/262144.0;
    }
    else
    {
        for (i=GLTEXCACHEADSIZ-1; i>=0; i--)
        {
            for (pth=texcache.list[i]; pth;)
            {
                next = pth->next;
                if (pth->flags & 16) // fullbright textures
                {
                    bglDeleteTextures(1,&pth->ofb->glpic);
                    Bfree(pth->ofb);
                }

                bglDeleteTextures(1,&pth->glpic);
                Bfree(pth);
                pth = next;
            }

            texcache.list[i] = NULL;
        }
        clearskins();
    }

    if (polymosttext)
        bglDeleteTextures(1,&polymosttext);
    polymosttext=0;

    freevbos();

    memset(texcache.list,0,sizeof(texcache.list));
    glox1 = -1;

    texcache_freeptrs();

    texcache_syncmemcache();
#ifdef DEBUGGINGAIDS
    OSD_Printf("polymost_glreset()\n");
#endif
}


// one-time initialization of OpenGL for polymost
void polymost_glinit()
{
    if (!Bstrcmp(glinfo.vendor, "NVIDIA Corporation"))
        bglHint(GL_FOG_HINT, GL_NICEST);
    else
        bglHint(GL_FOG_HINT, GL_DONT_CARE);

    bglFogi(GL_FOG_MODE, GL_EXP2);

    bglBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    bglPixelStorei(GL_PACK_ALIGNMENT, 1);
    bglPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    //bglHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
    //bglEnable(GL_LINE_SMOOTH);

    if (glmultisample > 0 && glinfo.multisample)
    {
        if (glinfo.nvmultisamplehint)
            bglHint(GL_MULTISAMPLE_FILTER_HINT_NV, glnvmultisamplehint ? GL_NICEST:GL_FASTEST);
        bglEnable(GL_MULTISAMPLE_ARB);
    }

    if (r_detailmapping && (!glinfo.multitex || !glinfo.envcombine))
    {
        OSD_Printf("Your OpenGL implementation doesn't support detail mapping. Disabling...\n");
        r_detailmapping = 0;
    }

    if (r_glowmapping && (!glinfo.multitex || !glinfo.envcombine))
    {
        OSD_Printf("Your OpenGL implementation doesn't support glow mapping. Disabling...\n");
        r_glowmapping = 0;
    }

    if (r_vbos && (!glinfo.vbos))
    {
        OSD_Printf("Your OpenGL implementation doesn't support Vertex Buffer Objects. Disabling...\n");
        r_vbos = 0;
    }

    bglEnableClientState(GL_VERTEX_ARRAY);
    bglEnableClientState(GL_TEXTURE_COORD_ARRAY);

    texcache_init();
    texcache_loadoffsets();
    texcache_openfiles();
    
    texcache_setupmemcache();
    texcache_checkgarbage();
}

////////// VISIBILITY FOG ROUTINES //////////
extern char nofog;  // in windows/SDL layers

// only for r_usenewshading!=2 (not preferred)
static void fogcalc_old(int32_t shade, int32_t vis)
{
    float f;

    bglFogi(GL_FOG_MODE, GL_EXP2);

    if (r_usenewshading==1)
    {
        f = 0.9f * shade;
        f = (vis > 239) ? (float)(gvisibility*((vis-240+f))) :
            (float)(gvisibility*(vis+16+f));
    }
    else
    {
        f = (shade < 0) ? shade * 3.5f : shade * .66f;
        f = (vis > 239) ? (float)(gvisibility*((vis-240+f)/(klabs(vis-256)))) :
            (float)(gvisibility*(vis+16+f));
    }

    if (f < 0.001f)
        f = 0.001f;
    else if (f > 100.0f)
        f = 100.0f;

    fogresult = f;
}

// For GL_LINEAR fog:
#define FOGDISTCONST 600
#define FULLVIS_BEGIN 2.9e38
#define FULLVIS_END 3.0e38

static inline void fogcalc(int32_t tile, int32_t shade, int32_t vis, int32_t pal)
{
    Bmemcpy(fogcol, &fogtable[pal<<2], sizeof(fogcol));

    if (getrendermode() == REND_POLYMOST && r_usetileshades && shade > 0 &&
        (!usehightile || !hicfindsubst(tile, pal, 0)) &&
        (!usemodels || md_tilehasmodel(tile, pal) < 0))
        shade >>= 1;

    if (r_usenewshading!=2)
    {
        fogcalc_old(shade, vis);
        return;
    }
    else
    {
        float combvis = (float)globalvisibility * (uint8_t)(vis+16);

        bglFogi(GL_FOG_MODE, GL_LINEAR);

        if (combvis == 0)
        {
            fogresult = FULLVIS_BEGIN;
            fogresult2 = FULLVIS_END;
            return;
        }

        fogresult = -(FOGDISTCONST * shade)/combvis;
        fogresult2 = (FOGDISTCONST * (numshades-1-shade))/combvis;
    }
}

void calc_and_apply_fog(int32_t tile, int32_t shade, int32_t vis, int32_t pal)
{
    if (nofog)
        return;

    fogcalc(tile, shade, vis, pal);
    bglFogfv(GL_FOG_COLOR, fogcol);

    if (r_usenewshading!=2)
    {
        bglFogf(GL_FOG_DENSITY, fogresult);
        return;
    }

    bglFogf(GL_FOG_START, fogresult);
    bglFogf(GL_FOG_END, fogresult2);
}

void calc_and_apply_fog_factor(int32_t tile, int32_t shade, int32_t vis, int32_t pal, float factor)
{
    if (nofog)
        return;

    fogcalc(tile, shade, vis, pal);
    bglFogfv(GL_FOG_COLOR, fogcol);

    if (r_usenewshading!=2)
    {
        bglFogf(GL_FOG_DENSITY, fogresult*factor);
        return;
    }

    bglFogf(GL_FOG_START, FULLVIS_BEGIN);
    bglFogf(GL_FOG_END, FULLVIS_END);
}
////////////////////


static float get_projhack_ratio(void)
{
    // Legacy widescreen
    if (glwidescreen && !r_usenewaspect)
        return 1.2f;

    if (glprojectionhacks == 1)
    {
        double mul = (gshang*gshang);
        return 1.05f + mul*mul*mul*mul;
    }

    if (glprojectionhacks == 2)
    {
        float abs_shang = fabs(gshang);
        if (abs_shang > 0.7f)
            return 1.05f + 4.f*(abs_shang-0.7f);
    }

    // No projection hacks (legacy or new-aspect)
    return 1.0f;
}

static void resizeglcheck(void)
{
    float m[4][4];

    if (glredbluemode < lastglredbluemode)
    {
        glox1 = -1;
        bglColorMask(1,1,1,1);
    }
    else if (glredbluemode != lastglredbluemode)
    {
        redblueclearcnt = 0;
    }
    lastglredbluemode = glredbluemode;

    //FUK
    if (lastglpolygonmode != glpolygonmode)
    {
        lastglpolygonmode = glpolygonmode;
        switch (glpolygonmode)
        {
        default:
        case 0:
            bglPolygonMode(GL_FRONT_AND_BACK,GL_FILL); break;
        case 1:
            bglPolygonMode(GL_FRONT_AND_BACK,GL_LINE); break;
        case 2:
            bglPolygonMode(GL_FRONT_AND_BACK,GL_POINT); break;
        }
    }
    if (glpolygonmode) //FUK
    {
        bglClearColor(1.0,1.0,1.0,0.0);
        bglClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
        bglDisable(GL_TEXTURE_2D);
    }

    if ((glox1 != windowx1) || (gloy1 != windowy1) || (glox2 != windowx2) || (gloy2 != windowy2))
    {
        const int32_t ourxdimen = (windowx2-windowx1+1);
        const float ratio = get_projhack_ratio();
        const int32_t fovcorrect = (ratio==0) ? 0 : (int32_t)(ourxdimen*ratio - ourxdimen);

        glox1 = (float)windowx1; gloy1 = (float)windowy1;
        glox2 = (float)windowx2; gloy2 = (float)windowy2;

        bglViewport(windowx1-(fovcorrect/2), yres-(windowy2+1),
                    ourxdimen+fovcorrect, windowy2-windowy1+1);

        bglMatrixMode(GL_PROJECTION);
        memset(m,0,sizeof(m));
        m[0][0] = (float)ydimen / ratio; m[0][2] = 1.0;
        m[1][1] = (float)xdimen; m[1][2] = 1.0;
        m[2][2] = 1.0; m[2][3] = (float)ydimen / ratio;
        m[3][2] =-1.0;
        bglLoadMatrixf(&m[0][0]);

        bglMatrixMode(GL_MODELVIEW);
        bglLoadIdentity();

#ifdef USE_OPENGL
        if (!nofog) bglEnable(GL_FOG);
#endif

        //bglEnable(GL_TEXTURE_2D);
    }
}

// NOTE: must not use DAPICNUM for indexing into tile arrays.
static void fixtransparency(int32_t dapicnum, coltype *dapic, int32_t daxsiz, int32_t daysiz,
                            int32_t daxsiz2, int32_t daysiz2, int32_t dameth)
{
    coltype *wpptr;
    int32_t j, x, y, r, g, b, dox, doy, naxsiz2;

    UNREFERENCED_PARAMETER(dapicnum);

    dox = daxsiz2-1; doy = daysiz2-1;
    if (dameth&4) { dox = min(dox,daxsiz); doy = min(doy,daysiz); }
    else { daxsiz = daxsiz2; daysiz = daysiz2; } //Make repeating textures duplicate top/left parts

    daxsiz--; daysiz--; naxsiz2 = -daxsiz2; //Hacks for optimization inside loop

    //Set transparent pixels to average color of neighboring opaque pixels
    //Doing this makes bilinear filtering look much better for masked textures (I.E. sprites)
    for (y=doy; y>=0; y--)
    {
        wpptr = &dapic[y*daxsiz2+dox];
        for (x=dox; x>=0; x--,wpptr--)
        {
            if (wpptr->a) continue;

            r = g = b = j = 0;
            if ((x>     0) && (wpptr[     -1].a)) { r += wpptr[     -1].r; g += wpptr[     -1].g; b += wpptr[     -1].b; j++; }
            if ((x<daxsiz) && (wpptr[     +1].a)) { r += wpptr[     +1].r; g += wpptr[     +1].g; b += wpptr[     +1].b; j++; }
            if ((y>     0) && (wpptr[naxsiz2].a)) { r += wpptr[naxsiz2].r; g += wpptr[naxsiz2].g; b += wpptr[naxsiz2].b; j++; }
            if ((y<daysiz) && (wpptr[daxsiz2].a)) { r += wpptr[daxsiz2].r; g += wpptr[daxsiz2].g; b += wpptr[daxsiz2].b; j++; }
            switch (j)
            {
            case 1:
                wpptr->r =   r            ; wpptr->g =   g            ; wpptr->b =   b            ; break;
            case 2:
                wpptr->r = ((r   +  1)>>1); wpptr->g = ((g   +  1)>>1); wpptr->b = ((b   +  1)>>1); break;
            case 3:
                wpptr->r = ((r*85+128)>>8); wpptr->g = ((g*85+128)>>8); wpptr->b = ((b*85+128)>>8); break;
            case 4:
                wpptr->r = ((r   +  2)>>2); wpptr->g = ((g   +  2)>>2); wpptr->b = ((b   +  2)>>2); break;
            default:
                break;
            }
        }
    }
}

void uploadtexture(int32_t doalloc, int32_t xsiz, int32_t ysiz, int32_t intexfmt, int32_t texfmt, coltype *pic, int32_t tsizx, int32_t tsizy, int32_t dameth)
{
    coltype *wpptr, *rpptr;
    int32_t x2, y2, j, js=0, x3, y3, y, x, r, g, b, a, k;
    int32_t hi = (dameth&8192)?1:0;
    int32_t nocompress = (dameth&4096)?1:0;

    dameth &= ~(8192|4096);

    if (gltexmaxsize <= 0)
    {
        GLint i = 0;
        bglGetIntegerv(GL_MAX_TEXTURE_SIZE, &i);
        if (!i) gltexmaxsize = 6;   // 2^6 = 64 == default GL max texture size
        else
        {
            gltexmaxsize = 0;
            for (; i>1; i>>=1) gltexmaxsize++;
        }
    }

    js = max(0,min(gltexmaxsize-1,gltexmiplevel));
    gltexmiplevel = js;
    while ((xsiz>>js) > (1<<gltexmaxsize) || (ysiz>>js) > (1<<gltexmaxsize)) js++;

    if (hi && !nocompress) js = r_downsize;

    /*
    OSD_Printf("Uploading %dx%d %s as %s\n", xsiz,ysiz,
            (texfmt==GL_RGBA?"GL_RGBA":
             texfmt==GL_RGB?"GL_RGB":
             texfmt==GL_BGR?"GL_BGR":
             texfmt==GL_BGRA?"GL_BGRA":"other"),
            (intexfmt==GL_RGBA?"GL_RGBA":
             intexfmt==GL_RGB?"GL_RGB":
             intexfmt==GL_COMPRESSED_RGBA_ARB?"GL_COMPRESSED_RGBA_ARB":
             intexfmt==GL_COMPRESSED_RGB_ARB?"GL_COMPRESSED_RGB_ARB":"other"));
    */

    if (js == 0)
    {
        if (doalloc&1)
            bglTexImage2D(GL_TEXTURE_2D,0,intexfmt,xsiz,ysiz,0,texfmt,GL_UNSIGNED_BYTE,pic); //loading 1st time
        else
            bglTexSubImage2D(GL_TEXTURE_2D,0,0,0,xsiz,ysiz,texfmt,GL_UNSIGNED_BYTE,pic); //overwrite old texture
    }

#if 0
    gluBuild2DMipmaps(GL_TEXTURE_2D,GL_RGBA8,xsiz,ysiz,texfmt,GL_UNSIGNED_BYTE,pic); //Needs C++ to link?
#elif 1
    x2 = xsiz; y2 = ysiz;
    for (j=1; (x2 > 1) || (y2 > 1); j++)
    {
        //x3 = ((x2+1)>>1); y3 = ((y2+1)>>1);
        x3 = max(1, x2 >> 1); y3 = max(1, y2 >> 1);		// this came from the GL_ARB_texture_non_power_of_two spec
        for (y=0; y<y3; y++)
        {
            wpptr = &pic[y*x3]; rpptr = &pic[(y<<1)*x2];
            for (x=0; x<x3; x++,wpptr++,rpptr+=2)
            {
                r = g = b = a = k = 0;
                if (rpptr[0].a)                  { r += rpptr[0].r; g += rpptr[0].g; b += rpptr[0].b; a += rpptr[0].a; k++; }
                if ((x+x+1 < x2) && (rpptr[1].a)) { r += rpptr[1].r; g += rpptr[1].g; b += rpptr[1].b; a += rpptr[1].a; k++; }
                if (y+y+1 < y2)
                {
                    if ((rpptr[x2].a)) { r += rpptr[x2  ].r; g += rpptr[x2  ].g; b += rpptr[x2  ].b; a += rpptr[x2  ].a; k++; }
                    if ((x+x+1 < x2) && (rpptr[x2+1].a)) { r += rpptr[x2+1].r; g += rpptr[x2+1].g; b += rpptr[x2+1].b; a += rpptr[x2+1].a; k++; }
                }
                switch (k)
                {
                case 0:
                case 1:
                    wpptr->r = r; wpptr->g = g; wpptr->b = b; wpptr->a = a; break;
                case 2:
                    wpptr->r = ((r+1)>>1); wpptr->g = ((g+1)>>1); wpptr->b = ((b+1)>>1); wpptr->a = ((a+1)>>1); break;
                case 3:
                    wpptr->r = ((r*85+128)>>8); wpptr->g = ((g*85+128)>>8); wpptr->b = ((b*85+128)>>8); wpptr->a = ((a*85+128)>>8); break;
                case 4:
                    wpptr->r = ((r+2)>>2); wpptr->g = ((g+2)>>2); wpptr->b = ((b+2)>>2); wpptr->a = ((a+2)>>2); break;
                default:
                    break;
                }
                //if (wpptr->a) wpptr->a = 255;
            }
        }
        if (tsizx >= 0) fixtransparency(-1, pic,(tsizx+(1<<j)-1)>>j,(tsizy+(1<<j)-1)>>j,x3,y3,dameth);
        if (j >= js)
        {
            if (doalloc&1)
                bglTexImage2D(GL_TEXTURE_2D,j-js,intexfmt,x3,y3,0,texfmt,GL_UNSIGNED_BYTE,pic); //loading 1st time
            else
                bglTexSubImage2D(GL_TEXTURE_2D,j-js,0,0,x3,y3,texfmt,GL_UNSIGNED_BYTE,pic); //overwrite old texture
        }
        x2 = x3; y2 = y3;
    }
#endif
}


#if 0
// TODO: make configurable
static int32_t tile_is_sky(int32_t tilenum)
{
    return return (tilenum >= 78 /*CLOUDYOCEAN*/ && tilenum <= 99 /*REDSKY2*/);
}
#else
# define tile_is_sky(x) (0)
#endif

static void texture_setup(int32_t dameth)
{
    gltexfiltermode = clamp(gltexfiltermode, 0, NUMGLFILTERMODES-1);
    bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, glfiltermodes[gltexfiltermode].mag);
    bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, glfiltermodes[gltexfiltermode].min);

    if (glinfo.maxanisotropy > 1.0)
    {
        if (glanisotropy <= 0 || glanisotropy > glinfo.maxanisotropy)
            glanisotropy = (int32_t)glinfo.maxanisotropy;
        bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, glanisotropy);
    }

    if (!(dameth&4))
    {
        bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, !tile_is_sky(dapic) ? GL_REPEAT:
                         (glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP));
        bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    }
    else
    {
        //For sprite textures, clamping looks better than wrapping
        bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
        bglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
    }
}

int32_t gloadtile_art(int32_t dapic, int32_t dapal, int32_t dashade, int32_t dameth, pthtyp *pth, int32_t doalloc)
{
    coltype *pic;
    int32_t xsiz, ysiz;
    char hasalpha = 0, hasfullbright = 0;

    static int32_t fullbrightloadingpass = 0;

    int32_t tsizx = tilesizx[dapic];
    int32_t tsizy = tilesizy[dapic];

    if (!glinfo.texnpot)
    {
        for (xsiz=1; xsiz<tsizx; xsiz+=xsiz);
        for (ysiz=1; ysiz<tsizy; ysiz+=ysiz);
    }
    else
    {
        if ((tsizx|tsizy) == 0)
        {
            xsiz = ysiz = 1;
        }
        else
        {
            xsiz = tsizx;
            ysiz = tsizy;
        }
    }

    pic = (coltype *)Bmalloc(xsiz*ysiz*sizeof(coltype));
    if (!pic) return 1;

    if (!waloff[dapic])
    {
        //Force invalid textures to draw something - an almost purely transparency texture
        //This allows the Z-buffer to be updated for mirrors (which are invalidated textures)
        pic[0].r = pic[0].g = pic[0].b = 0; pic[0].a = 1;
        tsizx = tsizy = 1; hasalpha = 1;
    }
    else
    {
        const int32_t dofullbright = !(picanm[dapic].sf&PICANM_NOFULLBRIGHT_BIT);
        int32_t y;

        for (y=0; y<ysiz; y++)
        {
            coltype *wpptr = &pic[y*xsiz];
            int32_t x, y2;

            if (y < tsizy) y2 = y; else y2 = y-tsizy;

            for (x=0; x<xsiz; x++,wpptr++)
            {
                int32_t dacol, x2;

                if ((dameth&4) && (x >= tsizx || y >= tsizy)) //Clamp texture
                    { wpptr->r = wpptr->g = wpptr->b = wpptr->a = 0; continue; }
                if (x < tsizx) x2 = x; else x2 = x-tsizx;

                dacol = *(char *)(waloff[dapic]+x2*tsizy+y2);

                if (!fullbrightloadingpass)
                {
                    // regular texture
                    if (dacol > 239 && dacol != 255 && dofullbright)
                        hasfullbright = 1;

                    wpptr->a = 255;
                }
                else
                {
                    // texture with only fullbright areas
                    if (dacol < 240)    // regular colors
                    {
                        wpptr->a = 0;
                        hasalpha = 1;
                    }
                    else   // fullbright
                    {
                        wpptr->a = 255;
                    }
                }

                if (dacol != 255)
                {
                    char *p = (char *)(palookup[dapal])+(int32_t)(dashade<<8);
                    dacol = (uint8_t)p[dacol];
                }
                else
                {
                    wpptr->a = 0;
                    hasalpha = 1;
                }

                bricolor((palette_t *)wpptr, dacol);
            }
        }
    }

    if (doalloc) bglGenTextures(1,(GLuint *)&pth->glpic); //# of textures (make OpenGL allocate structure)
    bglBindTexture(GL_TEXTURE_2D,pth->glpic);

    fixtransparency(dapic, pic,tsizx,tsizy,xsiz,ysiz,dameth);
    uploadtexture(doalloc,xsiz,ysiz,hasalpha?GL_RGBA:GL_RGB,GL_RGBA,pic,tsizx,tsizy,dameth);

    texture_setup(dameth);

    Bfree(pic);

    pth->picnum = dapic;
    pth->palnum = dapal;
    pth->shade = dashade;
    pth->effects = 0;
    pth->flags = ((dameth&4)>>2) | (hasalpha<<3);
    pth->hicr = NULL;

    if (hasfullbright && !fullbrightloadingpass)
    {
        // Load the ONLY texture that'll be assembled with the regular one to
        // make the final texture with fullbright pixels.
        fullbrightloadingpass = 1;
        pth->ofb = (pthtyp *)Bcalloc(1,sizeof(pthtyp));
        if (!pth->ofb) return 1;
        pth->flags |= (1<<4);
        if (gloadtile_art(dapic, dapal, 0, dameth, pth->ofb, 1)) return 1;

        fullbrightloadingpass = 0;
    }

    return 0;
}

int32_t gloadtile_hi(int32_t dapic,int32_t dapalnum, int32_t facen, hicreplctyp *hicr,
                            int32_t dameth, pthtyp *pth, int32_t doalloc, char effect)
{
    coltype *pic = NULL, *rpptr;
    int32_t j, x, y, xsiz=0, ysiz=0, tsizx, tsizy;

    char *picfil = NULL, *fn, hasalpha = 255;
    int32_t picfillen, texfmt = GL_RGBA, intexfmt = GL_RGBA, filh;

    int32_t gotcache;
    texcacheheader cachead;

    static coltype *lastpic = NULL;
    static char *lastfn = NULL;
    static int32_t lastsize = 0;

    int32_t startticks=0, willprint=0;

    if (!hicr) return -1;
    if (facen > 0)
    {
        if (!hicr->skybox) return -1;
        if (facen > 6) return -1;
        if (!hicr->skybox->face[facen-1]) return -1;
        fn = hicr->skybox->face[facen-1];
    }
    else
    {
        if (!hicr->filename) return -1;
        fn = hicr->filename;
    }

    if ((filh = kopen4load(fn, 0)) < 0)
    {
        OSD_Printf("hightile: %s (pic %d) not found\n", fn, dapic);
        if (facen > 0)
            hicr->skybox->ignore = 1;
        else
            hicr->ignore = 1;
        return -1;
    }
    picfillen = kfilelength(filh);

    kclose(filh);	// FIXME: shouldn't have to do this. bug in cache1d.c

    gotcache = texcache_readtexheader(fn, picfillen+(dapalnum<<8), dameth, effect, &cachead, 0);
    if (gotcache && !texcache_loadtile(&cachead, &doalloc, pth))
    {
        tsizx = cachead.xdim;
        tsizy = cachead.ydim;
        hasalpha = (cachead.flags & 2) ? 0 : 255;
    }
    else
    {
        int32_t r, g, b;

        gotcache = 0;	// the compressed version will be saved to disk

        if ((filh = kopen4load(fn, 0)) < 0) return -1;

        picfil = (char *)Bmalloc(picfillen+1); if (!picfil) { kclose(filh); return 1; }
        if (kread(filh, picfil, picfillen) != picfillen)
            initprintf("warning: didn't fully read %s\n", fn);
        // prevent
        // Conditional jump or move depends on uninitialised value(s)
        //  at kpegrend (kplib.c:1655)
        picfil[picfillen] = 0;
        kclose(filh);

        // tsizx/y = replacement texture's natural size
        // xsiz/y = 2^x size of replacement

        kpgetdim(picfil,picfillen,&tsizx,&tsizy);
        if (tsizx == 0 || tsizy == 0) { Bfree(picfil); return -1; }
        pth->sizx = tsizx;
        pth->sizy = tsizy;

        if (!glinfo.texnpot)
        {
            for (xsiz=1; xsiz<tsizx; xsiz+=xsiz);
            for (ysiz=1; ysiz<tsizy; ysiz+=ysiz);
        }
        else
        {
            xsiz = tsizx;
            ysiz = tsizy;
        }
        pic = (coltype *)Bcalloc(xsiz,ysiz*sizeof(coltype)); if (!pic) { Bfree(picfil); return 1; }

        startticks = getticks();

        if (lastpic && lastfn && !Bstrcmp(lastfn,fn))
        {
            willprint=1;
            Bmemcpy(pic, lastpic, xsiz*ysiz*sizeof(coltype));
        }
        else
        {
            if (kprender(picfil,picfillen,(intptr_t)pic,xsiz*sizeof(coltype),xsiz,ysiz,0,0)) { Bfree(picfil); Bfree(pic); return -2; }
            willprint=2;

            if (hicprecaching)
            {
                lastfn = fn;  // careful...
                if (!lastpic)
                {
                    lastpic = (coltype *)Bmalloc(xsiz*ysiz*sizeof(coltype));
                    lastsize = xsiz*ysiz;
                }
                else if (lastsize < xsiz*ysiz)
                {
                    Bfree(lastpic);
                    lastpic = (coltype *)Bmalloc(xsiz*ysiz*sizeof(coltype));
                }
                if (lastpic)
                    Bmemcpy(lastpic, pic, xsiz*ysiz*sizeof(coltype));
            }
            else if (lastpic)
            {
                Bfree(lastpic); lastpic=NULL;
                lastfn = NULL;
                lastsize = 0;
            }
        }

        r=(glinfo.bgra)?hictinting[dapalnum].r:hictinting[dapalnum].b;
        g=hictinting[dapalnum].g;
        b=(glinfo.bgra)?hictinting[dapalnum].b:hictinting[dapalnum].r;
        for (y=0,j=0; y<tsizy; y++,j+=xsiz)
        {
            coltype tcol;
            char *cptr = britable[gammabrightness ? 0 : curbrightness];
            rpptr = &pic[j];

            for (x=0; x<tsizx; x++)
            {
                tcol.b = cptr[rpptr[x].b];
                tcol.g = cptr[rpptr[x].g];
                tcol.r = cptr[rpptr[x].r];
                tcol.a = rpptr[x].a; hasalpha &= rpptr[x].a;

                if (effect & 1)
                {
                    // greyscale
                    tcol.b = max(tcol.b, max(tcol.g, tcol.r));
                    tcol.g = tcol.r = tcol.b;
                }
                if (effect & 2)
                {
                    // invert
                    tcol.b = 255-tcol.b;
                    tcol.g = 255-tcol.g;
                    tcol.r = 255-tcol.r;
                }
                if (effect & 4)
                {
                    // colorize
                    tcol.b = min((int32_t)((tcol.b)*r)/64,255);
                    tcol.g = min((int32_t)((tcol.g)*g)/64,255);
                    tcol.r = min((int32_t)((tcol.r)*b)/64,255);
                }

                rpptr[x].b = tcol.b;
                rpptr[x].g = tcol.g;
                rpptr[x].r = tcol.r;
                rpptr[x].a = tcol.a;
            }
        }

        if ((!(dameth&4)) || (facen)) //Duplicate texture pixels (wrapping tricks for non power of 2 texture sizes)
        {
            if (xsiz > tsizx) //Copy left to right
            {
                int32_t *lptr = (int32_t *)pic;
                for (y=0; y<tsizy; y++,lptr+=xsiz)
                    Bmemcpy(&lptr[tsizx],lptr,(xsiz-tsizx)<<2);
            }
            if (ysiz > tsizy)  //Copy top to bottom
                Bmemcpy(&pic[xsiz*tsizy],pic,(ysiz-tsizy)*xsiz<<2);
        }

        if (!glinfo.bgra)
        {
            for (j=xsiz*ysiz-1; j>=0; j--)
            {
                swapchar(&pic[j].r, &pic[j].b);
            }
        }
        else texfmt = GL_BGRA;

        Bfree(picfil); picfil = 0;

        if (tsizx>>r_downsize <= tilesizx[dapic] || tsizy>>r_downsize <= tilesizy[dapic])
            hicr->flags |= 17;

        if (glinfo.texcompr && glusetexcompr && !(hicr->flags & 1))
            intexfmt = (hasalpha == 255) ? GL_COMPRESSED_RGB_ARB : GL_COMPRESSED_RGBA_ARB;
        else if (hasalpha == 255) intexfmt = GL_RGB;

        if ((doalloc&3)==1)
            bglGenTextures(1, &pth->glpic); //# of textures (make OpenGL allocate structure)
        bglBindTexture(GL_TEXTURE_2D,pth->glpic);

        fixtransparency(-1, pic,tsizx,tsizy,xsiz,ysiz,dameth);
        uploadtexture(doalloc,xsiz,ysiz,intexfmt,texfmt,pic,-1,tsizy,dameth|8192|(hicr->flags & 16?4096:0));
    }

    // precalculate scaling parameters for replacement
    if (facen > 0)
    {
        pth->scalex = ((float)tsizx) / 64.0;
        pth->scaley = ((float)tsizy) / 64.0;
    }
    else
    {
        pth->scalex = ((float)tsizx) / ((float)tilesizx[dapic]);
        pth->scaley = ((float)tsizy) / ((float)tilesizy[dapic]);
    }

    texture_setup(dameth);

    Bfree(pic); pic=NULL;

    if (tsizx>>r_downsize <= tilesizx[dapic] || tsizy>>r_downsize <= tilesizy[dapic])
        hicr->flags |= (16+1);

    pth->picnum = dapic;
    pth->effects = effect;
    pth->flags = ((dameth&4)>>2) + 2 + ((facen>0)<<2); if (hasalpha != 255) pth->flags |= 8;
    pth->skyface = facen;
    pth->hicr = hicr;

    if (glinfo.texcompr && glusetexcompr && glusetexcache && !(hicr->flags & 1))
        if (!gotcache)
        {
            // save off the compressed version
            if (hicr->flags & 16) cachead.quality = 0;
            else cachead.quality = r_downsize;
            cachead.xdim = tsizx>>cachead.quality;
            cachead.ydim = tsizy>>cachead.quality;
            x = 0;
            for (j=0; j<31; j++)
            {
                if (xsiz == pow2long[j]) { x |= 1; }
                if (ysiz == pow2long[j]) { x |= 2; }
            }
            cachead.flags = (x!=3) | (hasalpha != 255 ? 2 : 0) | (hicr->flags&16 ? 8 : 0); // handle nocompress
///            OSD_Printf("Caching \"%s\"\n", fn);
            texcache_writetex(fn, picfillen+(dapalnum<<8), dameth, effect, &cachead);

            if (willprint)
            {
                int32_t etime = getticks()-startticks;
                if (etime>=MIN_CACHETIME_PRINT)
                    OSD_Printf("Load tile %4d: p%d-m%d-e%d %s... cached... %d ms\n", dapic, dapalnum, dameth, effect,
                               willprint==2 ? fn : "", etime);
                willprint = 0;
            }
            else
                OSD_Printf("Cached \"%s\"\n", fn);
        }

    if (willprint)
    {
        int32_t etime = getticks()-startticks;
        if (etime>=MIN_CACHETIME_PRINT)
            OSD_Printf("Load tile %4d: p%d-m%d-e%d %s... %d ms\n", dapic, dapalnum, dameth, effect,
                       willprint==2 ? fn : "", etime);
    }

    return 0;
}

#endif

//(dpx,dpy) specifies an n-sided polygon. The polygon must be a convex clockwise loop.
//    n must be <= 8 (assume clipping can double number of vertices)
//method: 0:solid, 1:masked(255 is transparent), 2:transluscent #1, 3:transluscent #2
//    +4 means it's a sprite, so wraparound isn't needed

// drawpoly's hack globals
static int32_t pow2xsplit = 0, skyclamphack = 0;
static float alpha = 0.f;

void drawpoly(double *dpx, double *dpy, int32_t n, int32_t method)
{
    double ngdx = 0.0, ngdy = 0.0, ngdo = 0.0, ngux = 0.0, nguy = 0.0, nguo = 0.0;
    double ngvx = 0.0, ngvy = 0.0, ngvo = 0.0, dp, up, vp, du0 = 0.0, du1 = 0.0, dui, duj;
    double f, r, ox, oy, oz, ox2, oy2, oz2, dd[16], uu[16], vv[16], px[16], py[16], uoffs;
    int32_t i, j, k, nn, ix0, ix1, tsizx, tsizy;
    int32_t xx, yy, dorot;
#ifdef USE_OPENGL
    pthtyp *pth, *detailpth, *glowpth;
    int32_t texunits = GL_TEXTURE0_ARB;
#endif
    // backup of the n for possible redrawing of fullbright
    int32_t n_ = n, method_ = method;

    if (method == -1) return;
#ifdef YAX_ENABLE
    if (g_nodraw) return;
#endif

    if (n == 3)
    {
        if ((dpx[0]-dpx[1])*(dpy[2]-dpy[1]) >= (dpx[2]-dpx[1])*(dpy[0]-dpy[1])) return; //for triangle
    }
    else
    {
        f = 0; //f is area of polygon / 2
        for (i=n-2,j=n-1,k=0; k<n; i=j,j=k,k++) f += (dpx[i]-dpx[k])*dpy[j];
        if (f <= 0) return;
    }

    //Load texture (globalpicnum)
    if ((uint32_t)globalpicnum >= MAXTILES) globalpicnum = 0;
    setgotpic(globalpicnum);
    tsizx = tilesizx[globalpicnum];
    tsizy = tilesizy[globalpicnum];
    if (palookup[globalpal] == NULL)
        globalpal = 0;
    if (!waloff[globalpicnum])
    {
        loadtile(globalpicnum);
        if (!waloff[globalpicnum])
        {
            if (getrendermode() < REND_POLYMOST) return;
            tsizx = tsizy = 1; method = 1; //Hack to update Z-buffer for invalid mirror textures
        }
    }

    j = 0; dorot = ((gchang != 1.0) || (gctang != 1.0));
    if (dorot)
    {
        for (i=0; i<n; i++)
        {
            ox = dpx[i]-ghalfx;
            oy = dpy[i]-ghoriz;
            oz = ghalfx;

            //Up/down rotation
            ox2 = ox;
            oy2 = oy*gchang - oz*gshang;
            oz2 = oy*gshang + oz*gchang;

            //Tilt rotation
            ox = ox2*gctang - oy2*gstang;
            oy = ox2*gstang + oy2*gctang;
            oz = oz2;

            r = ghalfx / oz;

            dd[j] = (dpx[i]*gdx + dpy[i]*gdy + gdo)*r;
            uu[j] = (dpx[i]*gux + dpy[i]*guy + guo)*r;
            vv[j] = (dpx[i]*gvx + dpy[i]*gvy + gvo)*r;

            px[j] = ox*r + ghalfx;
            py[j] = oy*r + ghoriz;
            if ((!j) || (px[j] != px[j-1]) || (py[j] != py[j-1])) j++;
        }
    }
    else
    {
        for (i=0; i<n; i++)
        {
            px[j] = dpx[i];
            py[j] = dpy[i];
            if ((!j) || (px[j] != px[j-1]) || (py[j] != py[j-1])) j++;
        }
    }
    while ((j >= 3) && (px[j-1] == px[0]) && (py[j-1] == py[0])) j--;
    if (j < 3) return;
    n = j;

#ifdef USE_OPENGL
    if (getrendermode() >= REND_POLYMOST)
    {
        float hackscx, hackscy;

        if (skyclamphack) method |= 4;
        pth = texcache_fetch(globalpicnum,globalpal,getpalookup(globvis>>2, globalshade),method&(~3));

        if (!pth)
        {
            if (editstatus)
            {
                Bsprintf(ptempbuf, "pth==NULL! (bad pal?) pic=%d pal=%d", globalpicnum, globalpal);
                polymost_printext256(8,8, editorcolors[15],editorcolors[5], ptempbuf, 0);
            }
            return;
        }

        if (r_fullbrights && pth->flags & 16)
            if (indrawroomsandmasks)
            {
                if (!fullbrightdrawingpass)
                    fullbrightdrawingpass = 1;
                else if (fullbrightdrawingpass == 2)
                    pth = pth->ofb;
            }

        // If we aren't rendmode 3, we're in Polymer, which means this code is
        // used for rotatesprite only. Polymer handles all the material stuff,
        // just submit the geometry and don't mess with textures.
        if (getrendermode() == REND_POLYMOST)
        {
            bglBindTexture(GL_TEXTURE_2D, pth ? pth->glpic : 0);

            if (srepeat)
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
            if (trepeat)
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
        }

        // texture scale by parkar request
        if (pth && pth->hicr && ((pth->hicr->xscale != 1.0f) || (pth->hicr->yscale != 1.0f)) && !drawingskybox)
        {
            bglMatrixMode(GL_TEXTURE);
            bglLoadIdentity();
            bglScalef(pth->hicr->xscale, pth->hicr->yscale, 1.0f);
            bglMatrixMode(GL_MODELVIEW);
        }

        // detail texture
        detailpth = NULL;
        if (r_detailmapping && usehightile && !drawingskybox &&
                hicfindsubst(globalpicnum, DETAILPAL, 0))
            detailpth = texcache_fetch(globalpicnum, DETAILPAL, 0, method&(~3));

        if (detailpth && detailpth->hicr && (detailpth->hicr->palnum == DETAILPAL))
        {
            polymost_setupdetailtexture(&texunits, detailpth ? detailpth->glpic : 0);

            f = detailpth ? detailpth->hicr->xscale : 1.0;

            bglMatrixMode(GL_TEXTURE);
            bglLoadIdentity();

            if (pth && pth->hicr && ((pth->hicr->xscale != 1.0f) || (pth->hicr->yscale != 1.0f)))
                bglScalef(pth->hicr->xscale, pth->hicr->yscale, 1.0f);

            if (detailpth && detailpth->hicr && ((detailpth->hicr->xscale != 1.0f) || (detailpth->hicr->yscale != 1.0f)))
                bglScalef(detailpth->hicr->xscale, detailpth->hicr->yscale, 1.0f);

            bglMatrixMode(GL_MODELVIEW);
        }

        // glow texture
        glowpth = NULL;
        if (r_glowmapping && usehightile && !drawingskybox &&
                hicfindsubst(globalpicnum, GLOWPAL, 0))
            glowpth = texcache_fetch(globalpicnum, GLOWPAL, 0, method&(~3));

        if (glowpth && glowpth->hicr && (glowpth->hicr->palnum == GLOWPAL))
            polymost_setupglowtexture(&texunits, glowpth ? glowpth->glpic : 0);

        if (pth && (pth->flags & 2))
        {
            hackscx = pth->scalex;
            hackscy = pth->scaley;
            tsizx = pth->sizx;
            tsizy = pth->sizy;
        }
        else { hackscx = 1.0; hackscy = 1.0; }

        if (!glinfo.texnpot)
        {
            for (xx=1; xx<tsizx; xx+=xx)
            {
                /* do nothing */
            }
            ox2 = (double)1.0/(double)xx;
            for (yy=1; yy<tsizy; yy+=yy)
            {
                /* do nothing */
            }
            oy2 = (double)1.0/(double)yy;
        }
        else
        {
            xx = tsizx; ox2 = (double)1.0/(double)xx;
            yy = tsizy; oy2 = (double)1.0/(double)yy;
        }

        if ((!(method&3)) && (!fullbrightdrawingpass))
        {
            bglDisable(GL_BLEND);
            bglDisable(GL_ALPHA_TEST);
        }
        else
        {
            float al = 0.0; // PLAG : default alphacut was 0.32 before goodalpha
            if (pth && pth->hicr && pth->hicr->alphacut >= 0.0) al = pth->hicr->alphacut;
            if (alphahackarray[globalpicnum])
                al=alphahackarray[globalpicnum];
            if (!waloff[globalpicnum]) al = 0.0;	// invalid textures ignore the alpha cutoff settings
            bglEnable(GL_BLEND);
            bglEnable(GL_ALPHA_TEST);
            bglAlphaFunc(GL_GREATER,al);
        }

        if (!dorot)
        {
            for (i=n-1; i>=0; i--)
            {
                dd[i] = px[i]*gdx + py[i]*gdy + gdo;
                uu[i] = px[i]*gux + py[i]*guy + guo;
                vv[i] = px[i]*gvx + py[i]*gvy + gvo;
            }
        }

        {
            float pc[4];
            pc[0] = pc[1] = pc[2] = getshadefactor(globalshade);

            switch (method&3)
            {
            default:
            case 0:
                pc[3] = 1.0f; break;
            case 1:
                pc[3] = 1.0f; break;
            case 2:
                pc[3] = 0.66f; break;
            case 3:
                pc[3] = 0.33f; break;
            }

            // spriteext full alpha control
            pc[3] *= 1.0f - alpha;

            // tinting happens only to hightile textures, and only if the texture we're
            // rendering isn't for the same palette as what we asked for
            if (!(hictinting[globalpal].f&4))
            {
                if (pth && (pth->flags & 2))
                {
                    if (pth->palnum != globalpal)
                    {
                        // apply tinting for replaced textures
                        pc[0] *= (float)hictinting[globalpal].r / 255.0;
                        pc[1] *= (float)hictinting[globalpal].g / 255.0;
                        pc[2] *= (float)hictinting[globalpal].b / 255.0;
                    }
                    if (hictinting[MAXPALOOKUPS-1].r != 255 || hictinting[MAXPALOOKUPS-1].g != 255 || hictinting[MAXPALOOKUPS-1].b != 255)
                    {
                        pc[0] *= (float)hictinting[MAXPALOOKUPS-1].r / 255.0;
                        pc[1] *= (float)hictinting[MAXPALOOKUPS-1].g / 255.0;
                        pc[2] *= (float)hictinting[MAXPALOOKUPS-1].b / 255.0;
                    }
                }
                // hack: this is for drawing the 8-bit crosshair recolored in polymost
                else if (hictinting[globalpal].f & 8)
                {
                    pc[0] *= (float)hictinting[globalpal].r / 255.0;
                    pc[1] *= (float)hictinting[globalpal].g / 255.0;
                    pc[2] *= (float)hictinting[globalpal].b / 255.0;
                }
            }

            bglColor4f(pc[0],pc[1],pc[2],pc[3]);
        }

        //Hack for walls&masked walls which use textures that are not a power of 2
        if ((pow2xsplit) && (tsizx != xx))
        {
            if (!dorot)
            {
                ngdx = gdx; ngdy = gdy; ngdo = gdo+(ngdx+ngdy)*.5;
                ngux = gux; nguy = guy; nguo = guo+(ngux+nguy)*.5;
                ngvx = gvx; ngvy = gvy; ngvo = gvo+(ngvx+ngvy)*.5;
            }
            else
            {
                ox = py[1]-py[2]; oy = py[2]-py[0]; oz = py[0]-py[1];
                r = 1.0 / (ox*px[0] + oy*px[1] + oz*px[2]);
                ngdx = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                ngux = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                ngvx = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                ox = px[2]-px[1]; oy = px[0]-px[2]; oz = px[1]-px[0];
                ngdy = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                nguy = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                ngvy = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                ox = px[0]-.5; oy = py[0]-.5; //.5 centers texture nicely
                ngdo = dd[0] - ox*ngdx - oy*ngdy;
                nguo = uu[0] - ox*ngux - oy*nguy;
                ngvo = vv[0] - ox*ngvx - oy*ngvy;
            }

            ngux *= hackscx; nguy *= hackscx; nguo *= hackscx;
            ngvx *= hackscy; ngvy *= hackscy; ngvo *= hackscy;
            uoffs = ((double)(xx-tsizx)*.5);
            ngux -= ngdx*uoffs;
            nguy -= ngdy*uoffs;
            nguo -= ngdo*uoffs;

            //Find min&max u coordinates (du0...du1)
            for (i=0; i<n; i++)
            {
                ox = px[i]; oy = py[i];
                f = (ox*ngux + oy*nguy + nguo) / (ox*ngdx + oy*ngdy + ngdo);
                if (!i) { du0 = du1 = f; continue; }
                if (f < du0) du0 = f;
                else if (f > du1) du1 = f;
            }

            f = 1.0/(double)tsizx;
            ix0 = (int32_t)floor(du0*f);
            ix1 = (int32_t)floor(du1*f);
            for (; ix0<=ix1; ix0++)
            {
                du0 = (double)((ix0)*tsizx);   // + uoffs;
                du1 = (double)((ix0+1)*tsizx); // + uoffs;

                i = 0; nn = 0;
                duj = (px[i]*ngux + py[i]*nguy + nguo) / (px[i]*ngdx + py[i]*ngdy + ngdo);
                do
                {
                    j = i+1; if (j == n) j = 0;

                    dui = duj; duj = (px[j]*ngux + py[j]*nguy + nguo) / (px[j]*ngdx + py[j]*ngdy + ngdo);

                    if ((du0 <= dui) && (dui <= du1)) { uu[nn] = px[i]; vv[nn] = py[i]; nn++; }
                    if (duj <= dui)
                    {
                        if ((du1 < duj) != (du1 < dui))
                        {
                            //ox*(ngux-ngdx*du1) + oy*(nguy-ngdy*du1) + (nguo-ngdo*du1) = 0
                            //(px[j]-px[i])*f + px[i] = ox
                            //(py[j]-py[i])*f + py[i] = oy

                            ///Solve for f
                            //((px[j]-px[i])*f + px[i])*(ngux-ngdx*du1) +
                            //((py[j]-py[i])*f + py[i])*(nguy-ngdy*du1) + (nguo-ngdo*du1) = 0

                            f = -(px[i] *(ngux-ngdx*du1) +  py[i]       *(nguy-ngdy*du1) + (nguo-ngdo*du1)) /
                                ((px[j]-px[i])*(ngux-ngdx*du1) + (py[j]-py[i])*(nguy-ngdy*du1));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                        if ((du0 < duj) != (du0 < dui))
                        {
                            f = -(px[i] *(ngux-ngdx*du0) +        py[i] *(nguy-ngdy*du0) + (nguo-ngdo*du0)) /
                                ((px[j]-px[i])*(ngux-ngdx*du0) + (py[j]-py[i])*(nguy-ngdy*du0));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                    }
                    else
                    {
                        if ((du0 < duj) != (du0 < dui))
                        {
                            f = -(px[i] *(ngux-ngdx*du0) +        py[i] *(nguy-ngdy*du0) + (nguo-ngdo*du0)) /
                                ((px[j]-px[i])*(ngux-ngdx*du0) + (py[j]-py[i])*(nguy-ngdy*du0));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                        if ((du1 < duj) != (du1 < dui))
                        {
                            f = -(px[i] *(ngux-ngdx*du1) +  py[i]       *(nguy-ngdy*du1) + (nguo-ngdo*du1)) /
                                ((px[j]-px[i])*(ngux-ngdx*du1) + (py[j]-py[i])*(nguy-ngdy*du1));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                    }
                    i = j;
                }
                while (i);
                if (nn < 3) continue;

                bglBegin(GL_TRIANGLE_FAN);
                for (i=0; i<nn; i++)
                {
                    ox = uu[i]; oy = vv[i];
                    dp = ox*ngdx + oy*ngdy + ngdo;
                    up = ox*ngux + oy*nguy + nguo;
                    vp = ox*ngvx + oy*ngvy + ngvo;
                    r = 1.0/dp;
                    if (texunits > GL_TEXTURE0_ARB)
                    {
                        j = GL_TEXTURE0_ARB;
                        while (j <= texunits)
                            bglMultiTexCoord2dARB(j++, (up*r-du0+uoffs)*ox2,vp*r*oy2);
                    }
                    else
                        bglTexCoord2d((up*r-du0+uoffs)*ox2,vp*r*oy2);
                    bglVertex3d((ox-ghalfx)*r*grhalfxdown10x,(ghoriz-oy)*r*grhalfxdown10,r*(1.0/1024.0));
                }
                bglEnd();
            }
        }
        else
        {
            ox2 *= hackscx; oy2 *= hackscy;
            bglBegin(GL_TRIANGLE_FAN);
            for (i=0; i<n; i++)
            {
                r = 1.0/dd[i];
                if (texunits > GL_TEXTURE0_ARB)
                {
                    j = GL_TEXTURE0_ARB;
                    while (j <= texunits)
                        bglMultiTexCoord2dARB(j++, uu[i]*r*ox2,vv[i]*r*oy2);
                }
                else
                    bglTexCoord2d(uu[i]*r*ox2,vv[i]*r*oy2);
                bglVertex3d((px[i]-ghalfx)*r*grhalfxdown10x,(ghoriz-py[i])*r*grhalfxdown10,r*(1.0/1024.0));
            }
            bglEnd();
        }

        while (texunits >= GL_TEXTURE0_ARB)
        {
            bglActiveTextureARB(texunits);
            bglMatrixMode(GL_TEXTURE);
            bglLoadIdentity();
            bglMatrixMode(GL_MODELVIEW);
            if (texunits > GL_TEXTURE0_ARB)
            {
                bglTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 1.0f);
                bglDisable(GL_TEXTURE_2D);
            }
            texunits--;
        }

        if (getrendermode() == REND_POLYMOST)
        {
            if (srepeat)
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
            if (trepeat)
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
        }

        if (fullbrightdrawingpass == 1) // tile has fullbright colors ?
        {
            int32_t shadeforfullbrightpass = globalshade; // save the current shade
            fullbrightdrawingpass = 2;
            globalshade = -128; // fullbright
            bglDisable(GL_FOG);
            drawpoly(dpx, dpy, n_, method_); // draw them afterwards, then. :)
            bglEnable(GL_FOG);
            globalshade = shadeforfullbrightpass;
            fullbrightdrawingpass = 0;
        }
        return;
    }
#endif

/*
    if (rendmode == 1)
    {
        if (method&3) //Only draw border around sprites/maskwalls
        {
            for (i=0,j=n-1; i<n; j=i,i++) drawline2d(px[i],py[i],px[j],py[j],31); //hopefully color index 31 is white
        }

        //ox = 0; oy = 0;
        //for(i=0;i<n;i++) { ox += px[i]; oy += py[i]; }
        //ox /= (double)n; oy /= (double)n;
        //for(i=0,j=n-1;i<n;j=i,i++) drawline2d(px[i]+(ox-px[i])*.125,py[i]+(oy-py[i])*.125,px[j]+(ox-px[j])*.125,py[j]+(oy-py[j])*.125,31);
    }
*/
}


static void vsp_finalize_init(vsptyp *vsp, int32_t vcnt)
{
    int32_t i;

    for (i=0; i<vcnt; i++)
    {
        vsp[i].cy[1] = vsp[i+1].cy[0]; vsp[i].ctag = i;
        vsp[i].fy[1] = vsp[i+1].fy[0]; vsp[i].ftag = i;
        vsp[i].n = i+1; vsp[i].p = i-1;
//        vsp[i].tag = -1;
    }
    vsp[vcnt-1].n = 0; vsp[0].p = vcnt-1;

    //VSPMAX-1 is dummy empty node
    for (i=vcnt; i<VSPMAX; i++) { vsp[i].n = i+1; vsp[i].p = i-1; }
    vsp[VSPMAX-1].n = vcnt; vsp[vcnt].p = VSPMAX-1;
}

/*Init viewport boundary (must be 4 point convex loop):
//      (px[0],py[0]).----.(px[1],py[1])
//                  /      \
//                /          \
// (px[3],py[3]).--------------.(px[2],py[2])
*/

void initmosts(double *px, double *py, int32_t n)
{
    int32_t i, j, k, imin, vcnt;

    vcnt = 1; //0 is dummy solid node

    if (n < 3) return;
    imin = (px[1] < px[0]);
    for (i=n-1; i>=2; i--) if (px[i] < px[imin]) imin = i;


    vsp[vcnt].x = px[imin];
    vsp[vcnt].cy[0] = vsp[vcnt].fy[0] = py[imin];
    vcnt++;
    i = imin+1; if (i >= n) i = 0;
    j = imin-1; if (j < 0) j = n-1;
    do
    {
        if (px[i] < px[j])
        {
            if ((vcnt > 1) && (px[i] <= vsp[vcnt-1].x)) vcnt--;
            vsp[vcnt].x = px[i];
            vsp[vcnt].cy[0] = py[i];
            k = j+1; if (k >= n) k = 0;
            //(px[k],py[k])
            //(px[i],?)
            //(px[j],py[j])
            vsp[vcnt].fy[0] = (px[i]-px[k])*(py[j]-py[k])/(px[j]-px[k]) + py[k];
            vcnt++;
            i++; if (i >= n) i = 0;
        }
        else if (px[j] < px[i])
        {
            if ((vcnt > 1) && (px[j] <= vsp[vcnt-1].x)) vcnt--;
            vsp[vcnt].x = px[j];
            vsp[vcnt].fy[0] = py[j];
            k = i-1; if (k < 0) k = n-1;
            //(px[k],py[k])
            //(px[j],?)
            //(px[i],py[i])
            vsp[vcnt].cy[0] = (px[j]-px[k])*(py[i]-py[k])/(px[i]-px[k]) + py[k];
            vcnt++;
            j--; if (j < 0) j = n-1;
        }
        else
        {
            if ((vcnt > 1) && (px[i] <= vsp[vcnt-1].x)) vcnt--;
            vsp[vcnt].x = px[i];
            vsp[vcnt].cy[0] = py[i];
            vsp[vcnt].fy[0] = py[j];
            vcnt++;
            i++; if (i >= n) i = 0; if (i == j) break;
            j--; if (j < 0) j = n-1;
        }
    }
    while (i != j);
    if (px[i] > vsp[vcnt-1].x)
    {
        vsp[vcnt].x = px[i];
        vsp[vcnt].cy[0] = vsp[vcnt].fy[0] = py[i];
        vcnt++;
    }

    vsp_finalize_init(vsp, vcnt);
    gtag = vcnt;
}

static inline void vsdel(vsptyp *vsp, int32_t i)
{
    int32_t pi, ni;
    //Delete i
    pi = vsp[i].p;
    ni = vsp[i].n;
    vsp[ni].p = pi;
    vsp[pi].n = ni;

    //Add i to empty list
    vsp[i].n = vsp[VSPMAX-1].n;
    vsp[i].p = VSPMAX-1;
    vsp[vsp[VSPMAX-1].n].p = i;
    vsp[VSPMAX-1].n = i;
}

static inline int32_t vsinsaft(vsptyp *vsp, int32_t i)
{
    int32_t r;
    //i = next element from empty list
    r = vsp[VSPMAX-1].n;
    vsp[vsp[r].n].p = VSPMAX-1;
    vsp[VSPMAX-1].n = vsp[r].n;

    vsp[r] = vsp[i]; //copy i to r

    //insert r after i
    vsp[r].p = i; vsp[r].n = vsp[i].n;
    vsp[vsp[i].n].p = r; vsp[i].n = r;

    return(r);
}

static inline int32_t testvisiblemost(float x0, float x1)
{
    int32_t i, newi;

    for (i=vsp[0].n; i; i=newi)
    {
        newi = vsp[i].n;
        if ((x0 < vsp[newi].x) && (vsp[i].x < x1) && (vsp[i].ctag >= 0)) return(1);
    }
    return(0);
}

static int32_t domostpolymethod = 0;

void domost(float x0, float y0, float x1, float y1)
{
    double dpx[4], dpy[4];
    float d, f, n, t, slop, dx, dx0, dx1, nx, nx0, ny0, nx1, ny1;
    float spx[4], /*spy[4],*/ cy[2], cv[2];
    int32_t i, j, k, z, ni, vcnt = 0, scnt, newi, dir, spt[4];

    alpha = 0.f;

    if (x0 < x1)
    {
        dir = 1; //clip dmost (floor)
        y0 -= .01f; y1 -= .01f;
    }
    else
    {
        if (x0 == x1) return;
        f = x0; x0 = x1; x1 = f;
        f = y0; y0 = y1; y1 = f;
        dir = 0; //clip umost (ceiling)
        //y0 += .01; y1 += .01; //necessary?
    }

    slop = (y1-y0)/(x1-x0);
    for (i=vsp[0].n; i; i=newi)
    {
        newi = vsp[i].n; nx0 = vsp[i].x; nx1 = vsp[newi].x;
        if ((x0 >= nx1) || (nx0 >= x1) || (vsp[i].ctag <= 0)) continue;
        dx = nx1-nx0;
        cy[0] = vsp[i].cy[0]; cv[0] = vsp[i].cy[1]-cy[0];
        cy[1] = vsp[i].fy[0]; cv[1] = vsp[i].fy[1]-cy[1];

        scnt = 0;

        //Test if left edge requires split (x0,y0) (nx0,cy(0)),<dx,cv(0)>
        if ((x0 > nx0) && (x0 < nx1))
        {
            t = (x0-nx0)*cv[dir] - (y0-cy[dir])*dx;
            if (((!dir) && (t < 0)) || ((dir) && (t > 0)))
                { spx[scnt] = x0; /*spy[scnt] = y0;*/ spt[scnt] = -1; scnt++; }
        }

        //Test for intersection on umost (j == 0) and dmost (j == 1)
        for (j=0; j<2; j++)
        {
            d = (y0-y1)*dx - (x0-x1)*cv[j];
            n = (y0-cy[j])*dx - (x0-nx0)*cv[j];
            if ((fabs(n) <= fabs(d)) && (d *n >= 0) && (d != 0))
            {
                t = n/d; nx = (x1-x0)*t + x0;
                if ((nx > nx0) && (nx < nx1))
                {
                    spx[scnt] = nx; /* spy[scnt] = (y1-y0)*t + y0; */
                    spt[scnt] = j; scnt++;
                }
            }
        }

        //Nice hack to avoid full sort later :)
        if ((scnt >= 2) && (spx[scnt-1] < spx[scnt-2]))
        {
            f = spx[scnt-1]; spx[scnt-1] = spx[scnt-2]; spx[scnt-2] = f;
            /* f = spy[scnt-1]; spy[scnt-1] = spy[scnt-2]; spy[scnt-2] = f; */
            j = spt[scnt-1]; spt[scnt-1] = spt[scnt-2]; spt[scnt-2] = j;
        }

        //Test if right edge requires split
        if ((x1 > nx0) && (x1 < nx1))
        {
            t = (x1-nx0)*cv[dir] - (y1-cy[dir])*dx;
            if (((!dir) && (t < 0)) || ((dir) && (t > 0)))
                { spx[scnt] = x1; /* spy[scnt] = y1; */ spt[scnt] = -1; scnt++; }
        }

        vsp[i].tag = vsp[newi].tag = -1;
        for (z=0; z<=scnt; z++,i=vcnt)
        {
            if (z < scnt)
            {
                vcnt = vsinsaft(vsp, i);
                t = (spx[z]-nx0)/dx;
                vsp[i].cy[1] = t*cv[0] + cy[0];
                vsp[i].fy[1] = t*cv[1] + cy[1];
                vsp[vcnt].x = spx[z];
                vsp[vcnt].cy[0] = vsp[i].cy[1];
                vsp[vcnt].fy[0] = vsp[i].fy[1];
                vsp[vcnt].tag = spt[z];
            }

            ni = vsp[i].n; if (!ni) continue; //this 'if' fixes many bugs!
            dx0 = vsp[i].x; if (x0 > dx0) continue;
            dx1 = vsp[ni].x; if (x1 < dx1) continue;
            ny0 = (dx0-x0)*slop + y0;
            ny1 = (dx1-x0)*slop + y0;

            //      dx0           dx1
            //       ~             ~
            //----------------------------
            //     t0+=0         t1+=0
            //   vsp[i].cy[0]  vsp[i].cy[1]
            //============================
            //     t0+=1         t1+=3
            //============================
            //   vsp[i].fy[0]    vsp[i].fy[1]
            //     t0+=2         t1+=6
            //
            //     ny0 ?         ny1 ?

            k = 1+3;
            if ((vsp[i].tag == 0) || (ny0 <= vsp[i].cy[0]+.01)) k--;
            if ((vsp[i].tag == 1) || (ny0 >= vsp[i].fy[0]-.01)) k++;
            if ((vsp[ni].tag == 0) || (ny1 <= vsp[i].cy[1]+.01)) k -= 3;
            if ((vsp[ni].tag == 1) || (ny1 >= vsp[i].fy[1]-.01)) k += 3;

            if (!dir)
            {
                dpx[0] = dx0; dpy[0] = vsp[i].cy[0];
                dpx[1] = dx1; dpy[1] = vsp[i].cy[1];

                switch (k)
                {
                case 1:
                case 2:
                    dpx[2] = dx0; dpy[2] = ny0; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].cy[0] = ny0; vsp[i].ctag = gtag; break;
                case 3:
                case 6:
                    dpx[2] = dx1; dpy[2] = ny1; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].cy[1] = ny1; vsp[i].ctag = gtag; break;
                case 4:
                case 5:
                case 7:
                    dpx[2] = dx1; dpy[2] = ny1;
                    dpx[3] = dx0; dpy[3] = ny0; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].cy[0] = ny0; vsp[i].cy[1] = ny1; vsp[i].ctag = gtag; break;
                case 8:
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1];
                    dpx[3] = dx0; dpy[3] = vsp[i].fy[0]; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].ctag = vsp[i].ftag = -1; break;
                default:
                    break;
                }
            }
            else
            {
                switch (k)
                {
                case 7:
                case 6:
                    dpx[0] = dx0; dpy[0] = ny0;
                    dpx[1] = dx1; dpy[1] = vsp[i].fy[1];
                    dpx[2] = dx0; dpy[2] = vsp[i].fy[0]; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].fy[0] = ny0; vsp[i].ftag = gtag; break;
                case 5:
                case 2:
                    dpx[0] = dx0; dpy[0] = vsp[i].fy[0];
                    dpx[1] = dx1; dpy[1] = ny1;
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1]; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].fy[1] = ny1; vsp[i].ftag = gtag; break;
                case 4:
                case 3:
                case 1:
                    dpx[0] = dx0; dpy[0] = ny0;
                    dpx[1] = dx1; dpy[1] = ny1;
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1];
                    dpx[3] = dx0; dpy[3] = vsp[i].fy[0]; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].fy[0] = ny0; vsp[i].fy[1] = ny1; vsp[i].ftag = gtag; break;
                case 0:
                    dpx[0] = dx0; dpy[0] = vsp[i].cy[0];
                    dpx[1] = dx1; dpy[1] = vsp[i].cy[1];
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1];
                    dpx[3] = dx0; dpy[3] = vsp[i].fy[0]; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].ctag = vsp[i].ftag = -1; break;
                default:
                    break;
                }
            }
        }
    }

    gtag++;

    //Combine neighboring vertical strips with matching collinear top&bottom edges
    //This prevents x-splits from propagating through the entire scan
    i = vsp[0].n;
    while (i)
    {
        ni = vsp[i].n;

        if ((vsp[i].cy[0] >= vsp[i].fy[0]) && (vsp[i].cy[1] >= vsp[i].fy[1]))
            vsp[i].ctag = vsp[i].ftag = -1;

        if ((vsp[i].ctag == vsp[ni].ctag) && (vsp[i].ftag == vsp[ni].ftag))
        {
            vsp[i].cy[1] = vsp[ni].cy[1];
            vsp[i].fy[1] = vsp[ni].fy[1];
            vsdel(vsp, ni);
        }
        else i = ni;
    }
}

void polymost_scansector(int32_t sectnum);

// variables that are set to ceiling- or floor-members, depending
// on which one is processed right now
static int32_t global_cf_z;
static float global_cf_xpanning, global_cf_ypanning, global_cf_heinum;
static int32_t global_cf_shade, global_cf_pal;
static int32_t (*global_getzofslope_func)(int16_t, int32_t, int32_t);

static void polymost_internal_nonparallaxed(double nx0, double ny0, double nx1, double ny1, double ryp0, double ryp1,
                                            double x0, double x1, double cf_y0, double cf_y1, int32_t have_floor,
                                            int32_t sectnum)
{
    double ft[4], fx, fy, ox, oy, oz, ox2, oy2;
    double px[3], py[3], dd[3], uu[3], vv[3], r;
    int32_t i;

    const sectortype *sec = &sector[sectnum];

    // comments from floor code:
            //(singlobalang/-16384*(sx-ghalfx) + 0*(sy-ghoriz) + (cosviewingrangeglobalang/16384)*ghalfx)*d + globalposx    = u*16
            //(cosglobalang/ 16384*(sx-ghalfx) + 0*(sy-ghoriz) + (sinviewingrangeglobalang/16384)*ghalfx)*d + globalposy    = v*16
            //(                  0*(sx-ghalfx) + 1*(sy-ghoriz) + (                             0)*ghalfx)*d + globalposz/16 = (sec->floorz/16)
    if (!(globalorientation&64))
        { ft[0] = globalposx; ft[1] = globalposy; ft[2] = cosglobalang; ft[3] = singlobalang; }
    else
    {
        //relative alignment
        fx = (double)(wall[wall[sec->wallptr].point2].x-wall[sec->wallptr].x);
        fy = (double)(wall[wall[sec->wallptr].point2].y-wall[sec->wallptr].y);
        r = 1.0/sqrt(fx*fx+fy*fy); fx *= r; fy *= r;
        ft[2] = cosglobalang*fx + singlobalang*fy;
        ft[3] = singlobalang*fx - cosglobalang*fy;
        ft[0] = ((double)(globalposx-wall[sec->wallptr].x))*fx + ((double)(globalposy-wall[sec->wallptr].y))*fy;
        ft[1] = ((double)(globalposy-wall[sec->wallptr].y))*fx - ((double)(globalposx-wall[sec->wallptr].x))*fy;
        if (!(globalorientation&4)) globalorientation ^= 32; else globalorientation ^= 16;
    }
    gdx = 0;
    gdy = gxyaspect;
    if (!(globalorientation&2))
        if (global_cf_z-globalposz)  // PK 2012: don't allow div by zero
            gdy /= (double)(global_cf_z-globalposz);
    gdo = -ghoriz*gdy;
    if (globalorientation&8) { ft[0] /= 8; ft[1] /= -8; ft[2] /= 2097152; ft[3] /= 2097152; }
    else { ft[0] /= 16; ft[1] /= -16; ft[2] /= 4194304; ft[3] /= 4194304; }
    gux = (double)ft[3]*((double)viewingrange)/-65536.0;
    gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
    guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
    guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
    guo += (double)(ft[2]-gux)*ghalfx;
    gvo -= (double)(ft[3]+gvx)*ghalfx;

    //Texture flipping
    if (globalorientation&4)
    {
        r = gux; gux = gvx; gvx = r;
        r = guy; guy = gvy; gvy = r;
        r = guo; guo = gvo; gvo = r;
    }
    if (globalorientation&16) { gux = -gux; guy = -guy; guo = -guo; }
    if (globalorientation&32) { gvx = -gvx; gvy = -gvy; gvo = -gvo; }

    //Texture panning
    fx = global_cf_xpanning*((float)(1<<(picsiz[globalpicnum]&15)))/256.0;
    fy = global_cf_ypanning*((float)(1<<(picsiz[globalpicnum]>>4)))/256.0;
    if ((globalorientation&(2+64)) == (2+64)) //Hack for panning for slopes w/ relative alignment
    {
        r = global_cf_heinum / 4096.0; r = 1.0/sqrt(r*r+1);
        if (!(globalorientation&4)) fy *= r; else fx *= r;
    }
    guy += gdy*fx; guo += gdo*fx;
    gvy += gdy*fy; gvo += gdo*fy;

    if (globalorientation&2) //slopes
    {
        px[0] = x0; py[0] = ryp0 + ghoriz;
        px[1] = x1; py[1] = ryp1 + ghoriz;

        //Pick some point guaranteed to be not collinear to the 1st two points
        ox = nx0 + (ny1-ny0);
        oy = ny0 + (nx0-nx1);
        ox2 = (double)(oy-globalposy)*gcosang  - (double)(ox-globalposx)*gsinang ;
        oy2 = (double)(ox-globalposx)*gcosang2 + (double)(oy-globalposy)*gsinang2;
        oy2 = 1.0/oy2;
        px[2] = ghalfx*ox2*oy2 + ghalfx; oy2 *= gyxscale;
        py[2] = oy2 + ghoriz;

        for (i=0; i<3; i++)
        {
            dd[i] = px[i]*gdx + py[i]*gdy + gdo;
            uu[i] = px[i]*gux + py[i]*guy + guo;
            vv[i] = px[i]*gvx + py[i]*gvy + gvo;
        }

        py[0] = cf_y0;
        py[1] = cf_y1;
        py[2] = (global_getzofslope_func(sectnum,(int32_t)ox,(int32_t)oy)-globalposz)*oy2 + ghoriz;

        ox = py[1]-py[2]; oy = py[2]-py[0]; oz = py[0]-py[1];
        r = 1.0 / (ox*px[0] + oy*px[1] + oz*px[2]);
        gdx = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
        gux = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
        gvx = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
        ox = px[2]-px[1]; oy = px[0]-px[2]; oz = px[1]-px[0];
        gdy = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
        guy = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
        gvy = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
        gdo = dd[0] - px[0]*gdx - py[0]*gdy;
        guo = uu[0] - px[0]*gux - py[0]*guy;
        gvo = vv[0] - px[0]*gvx - py[0]*gvy;

        if (globalorientation&64) //Hack for relative alignment on slopes
        {
            r = global_cf_heinum / 4096.0;
            r = sqrt(r*r+1);
            if (!(globalorientation&4)) { gvx *= r; gvy *= r; gvo *= r; }
            else { gux *= r; guy *= r; guo *= r; }
        }
    }
    domostpolymethod = (globalorientation>>7)&3;
    if (have_floor)
    {
        if (globalposz >= getflorzofslope(sectnum,globalposx,globalposy)) domostpolymethod = -1; //Back-face culling
    }
    else
    {
        if (globalposz <= getceilzofslope(sectnum,globalposx,globalposy)) domostpolymethod = -1; //Back-face culling
    }

    calc_and_apply_fog(globalpicnum, global_cf_shade, sec->visibility, global_cf_pal);

    pow2xsplit = 0;
    alpha = 0.f;
    if (have_floor)
        domost(x0,cf_y0,x1,cf_y1); //flor
    else
        domost(x1,cf_y1,x0,cf_y0); //ceil
    domostpolymethod = 0;
}

static void calc_ypanning(int32_t refposz, double ryp0, double ryp1,
                          double x0, double x1, uint8_t ypan, uint8_t yrepeat,
                          int32_t dopancor)
{
    int32_t i;
    double t0, t1, t, fy;
    int32_t yoffs;  // for panning "correction"

    t0 = ((float)(refposz-globalposz))*ryp0 + ghoriz;
    t1 = ((float)(refposz-globalposz))*ryp1 + ghoriz;
    t = ((gdx*x0 + gdo) * (float)yrepeat) / ((x1-x0) * ryp0 * 2048.f);
    i = (1<<(picsiz[globalpicnum]>>4)); if (i < tilesizy[globalpicnum]) i <<= 1;

    if (dopancor)
    {
        ftol((i-tilesizy[globalpicnum])*(255.f/i), &yoffs);

        if (ypan>256-yoffs)
        {
            ypan-=yoffs;
        }
    }
    else
    {
        // (1)
        // not hacked yet

        // (2)
        // Still need a hack, depending on the wall(height,ypanning,yrepeat,tilesizy)
        // it should do "ypan-=yoffs" or "ypan+=yoffs" or [nothing].
        // Example: the film projector in the E1L1.map needs "ypan-=yoffs"
    }

    fy = (float)ypan * ((float)i) / 256.0;
    gvx = (t0-t1)*t;
    gvy = (x1-x0)*t;
    gvo = -gvx*x0 - gvy*t0 + fy*gdo; gvx += fy*gdx; gvy += fy*gdy;
}


static void polymost_drawalls(int32_t bunch)
{
    sectortype *sec, *nextsec;
    walltype *wal, *wal2, *nwal;
    double ox, oy, oz, dd[3], vv[3];
    double fx, x0, x1, cy0, cy1, fy0, fy1, xp0, yp0, xp1, yp1, ryp0, ryp1, nx0, ny0, nx1, ny1;
    double t, r, t0, t1, ocy0, ocy1, ofy0, ofy1, oxp0, oyp0, ft[4];
    double oguo, ogux, oguy;
    int32_t i, x, y, z, cz, fz, wallnum, sectnum, nextsectnum;

    int16_t dapskybits;
    static const int16_t zeropskyoff[MAXPSKYTILES] = { 0 };
    const int16_t *dapskyoff;

    alpha = 0.f;

    sectnum = thesector[bunchfirst[bunch]]; sec = &sector[sectnum];

    //DRAW WALLS SECTION!
    for (z=bunchfirst[bunch]; z>=0; z=p2[z])
    {
        wallnum = thewall[z]; wal = &wall[wallnum]; wal2 = &wall[wal->point2];
        nextsectnum = wal->nextsector;
        nextsec = nextsectnum>=0 ? &sector[nextsectnum] : NULL;

#ifdef YAX_ENABLE
        if (yax_nomaskpass==1 && yax_isislandwall(wallnum, !yax_globalcf) && (yax_nomaskdidit=1))
            continue;
#endif

        //Offset&Rotate 3D coordinates to screen 3D space
        x = wal->x-globalposx; y = wal->y-globalposy;
        xp0 = (double)y*gcosang  - (double)x*gsinang;
        yp0 = (double)x*gcosang2 + (double)y*gsinang2;
        x = wal2->x-globalposx; y = wal2->y-globalposy;
        xp1 = (double)y*gcosang  - (double)x*gsinang;
        yp1 = (double)x*gcosang2 + (double)y*gsinang2;

        oxp0 = xp0; oyp0 = yp0;

        //Clip to close parallel-screen plane
        if (yp0 < SCISDIST)
        {
            if (yp1 < SCISDIST) continue;
            t0 = (SCISDIST-yp0)/(yp1-yp0); xp0 = (xp1-xp0)*t0+xp0; yp0 = SCISDIST;
            nx0 = (wal2->x-wal->x)*t0+wal->x;
            ny0 = (wal2->y-wal->y)*t0+wal->y;
        }
        else { t0 = 0.f; nx0 = wal->x; ny0 = wal->y; }
        if (yp1 < SCISDIST)
        {
            t1 = (SCISDIST-oyp0)/(yp1-oyp0); xp1 = (xp1-oxp0)*t1+oxp0; yp1 = SCISDIST;
            nx1 = (wal2->x-wal->x)*t1+wal->x;
            ny1 = (wal2->y-wal->y)*t1+wal->y;
        }
        else { t1 = 1.f; nx1 = wal2->x; ny1 = wal2->y; }

        ryp0 = 1.f/yp0; ryp1 = 1.f/yp1;

        //Generate screen coordinates for front side of wall
        x0 = ghalfx*xp0*ryp0 + ghalfx;
        x1 = ghalfx*xp1*ryp1 + ghalfx;
        if (x1 <= x0) continue;

        ryp0 *= gyxscale; ryp1 *= gyxscale;

        getzsofslope(sectnum,(int32_t)nx0,(int32_t)ny0,&cz,&fz);
        cy0 = ((float)(cz-globalposz))*ryp0 + ghoriz;
        fy0 = ((float)(fz-globalposz))*ryp0 + ghoriz;
        getzsofslope(sectnum,(int32_t)nx1,(int32_t)ny1,&cz,&fz);
        cy1 = ((float)(cz-globalposz))*ryp1 + ghoriz;
        fy1 = ((float)(fz-globalposz))*ryp1 + ghoriz;

        globalpicnum = sec->floorpicnum; globalshade = sec->floorshade; globalpal = (int32_t)((uint8_t)sec->floorpal);
        globalorientation = sec->floorstat;
        globvis = globalcisibility;
        if (sector[sectnum].visibility != 0) globvis = mulscale4(globvis, (uint8_t)(sector[sectnum].visibility+16));

        DO_TILE_ANIM(globalpicnum, sectnum);

        // multi-psky stuff
        dapskyoff = zeropskyoff;
        dapskybits = pskybits;

        for (i=0; i<pskynummultis; i++)
        {
            if (globalpicnum == pskymultilist[i])
            {
                dapskybits = pskymultibits[i];
                dapskyoff = pskymultioff[i];
                break;
            }
        }
        //

        global_cf_shade = sec->floorshade, global_cf_pal = sec->floorpal; global_cf_z = sec->floorz;  // REFACT
        global_cf_xpanning = sec->floorxpanning; global_cf_ypanning = sec->floorypanning, global_cf_heinum = sec->floorheinum;
        global_getzofslope_func = &getflorzofslope;

        if (!(globalorientation&1))
        {
#ifdef YAX_ENABLE
            if (globalposz <= sec->floorz || yax_getbunch(sectnum, YAX_FLOOR) < 0 || yax_getnextwall(wallnum, YAX_FLOOR) >= 0)
#endif
                polymost_internal_nonparallaxed(nx0, ny0, nx1, ny1, ryp0, ryp1, x0, x1, fy0, fy1, 1, sectnum);
        }
        else if ((nextsectnum < 0) || (!(sector[nextsectnum].floorstat&1)))
        {
            //Parallaxing sky... hacked for Ken's mountain texture; paper-sky only :/
#ifdef USE_OPENGL
            if (getrendermode() >= REND_POLYMOST)
            {
                calc_and_apply_fog_factor(sec->floorpicnum, sec->floorshade, sec->visibility, sec->floorpal, 0.005);

                //Use clamping for tiled sky textures
                for (i=(1<<dapskybits)-1; i>0; i--)
                    if (dapskyoff[i] != dapskyoff[i-1])
                        { skyclamphack = r_parallaxskyclamping; break; }
            }
#endif
            if (bpp == 8 || !usehightile || !hicfindsubst(globalpicnum,globalpal,1))
            {
                dd[0] = (float)xdimen*.0000001; //Adjust sky depth based on screen size!
                t = (double)((1<<(picsiz[globalpicnum]&15))<<dapskybits);
                vv[1] = dd[0]*((double)xdimscale*(double)viewingrange)/(65536.0*65536.0);
                vv[0] = dd[0]*((double)((tilesizy[globalpicnum]>>1)+parallaxyoffs)) - vv[1]*ghoriz;
                i = (1<<(picsiz[globalpicnum]>>4)); if (i != tilesizy[globalpicnum]) i += i;

                //Hack to draw black rectangle below sky when looking down...
                gdx = 0; gdy = gxyaspect / 262144.0; gdo = -ghoriz*gdy;
                gux = 0; guy = 0; guo = 0;
                gvx = 0; gvy = (double)(tilesizy[globalpicnum]-1)*gdy; gvo = (double)(tilesizy[globalpicnum-1])*gdo;
                oy = (((double)tilesizy[globalpicnum])*dd[0]-vv[0])/vv[1];
                if ((oy > fy0) && (oy > fy1)) domost(x0,oy,x1,oy);
                else if ((oy > fy0) != (oy > fy1))
                {
                    //  fy0                      fy1
                    //     \                    /
                    //oy----------      oy----------
                    //        \              /
                    //         fy1        fy0
                    ox = (oy-fy0)*(x1-x0)/(fy1-fy0) + x0;
                    if (oy > fy0) { domost(x0,oy,ox,oy); domost(ox,oy,x1,fy1); }
                    else { domost(x0,fy0,ox,oy); domost(ox,oy,x1,oy); }
                }
                else domost(x0,fy0,x1,fy1);

                if (r_parallaxskypanning)
                    vv[0] += dd[0]*((double)sec->floorypanning)*((double)i)/256.0;

                gdx = 0; gdy = 0; gdo = dd[0];
                gux = gdo*(t*((double)xdimscale)*((double)yxaspect)*((double)viewingrange))/(16384.0*65536.0*65536.0*5.0*1024.0);
                guy = 0; //guo calculated later
                gvx = 0; gvy = vv[1]; gvo = vv[0];

                i = globalpicnum; r = (fy1-fy0)/(x1-x0); //slope of line
                oy = ((double)viewingrange)/(ghalfx*256.0); oz = 1/oy;

                y = ((((int32_t)((x0-ghalfx)*oy))+globalang)>>(11-dapskybits));
                fx = x0;
                do
                {
                    globalpicnum = dapskyoff[y&((1<<dapskybits)-1)]+i;
                    guo = gdo*(t*((double)(globalang-(y<<(11-dapskybits))))/2048.0 + (double)((r_parallaxskypanning)?sec->floorxpanning:0)) - gux*ghalfx;
                    y++;
                    ox = fx; fx = ((double)((y<<(11-dapskybits))-globalang))*oz+ghalfx;
                    if (fx > x1) { fx = x1; i = -1; }

                    pow2xsplit = 0; domost(ox,(ox-x0)*r+fy0,fx,(fx-x0)*r+fy0); //flor
                }
                while (i >= 0);
            }
            else  //NOTE: code copied from ceiling code... lots of duplicated stuff :/
            {
                //Skybox code for parallax ceiling!
                double _xp0, _yp0, _xp1, _yp1, _oxp0, _oyp0, _t0, _t1; // _nx0, _ny0, _nx1, _ny1;
                double _ryp0, _ryp1, _x0, _x1, _cy0, _fy0, _cy1, _fy1, _ox0, _ox1;
                double nfy0, nfy1;
                int32_t skywalx[4] = {-512,512,512,-512}, skywaly[4] = {-512,-512,512,512};

                pow2xsplit = 0;
                skyclamphack = 1;

                for (i=0; i<4; i++)
                {
                    x = skywalx[i&3]; y = skywaly[i&3];
                    _xp0 = (double)y*gcosang  - (double)x*gsinang;
                    _yp0 = (double)x*gcosang2 + (double)y*gsinang2;
                    x = skywalx[(i+1)&3]; y = skywaly[(i+1)&3];
                    _xp1 = (double)y*gcosang  - (double)x*gsinang;
                    _yp1 = (double)x*gcosang2 + (double)y*gsinang2;

                    _oxp0 = _xp0; _oyp0 = _yp0;

                    //Clip to close parallel-screen plane
                    if (_yp0 < SCISDIST)
                    {
                        if (_yp1 < SCISDIST) continue;
                        _t0 = (SCISDIST-_yp0)/(_yp1-_yp0); _xp0 = (_xp1-_xp0)*_t0+_xp0; _yp0 = SCISDIST;
//                        _nx0 = (skywalx[(i+1)&3]-skywalx[i&3])*_t0+skywalx[i&3];
//                        _ny0 = (skywaly[(i+1)&3]-skywaly[i&3])*_t0+skywaly[i&3];
                    }
                    else { _t0 = 0.f; /*_nx0 = skywalx[i&3]; _ny0 = skywaly[i&3];*/ }
                    if (_yp1 < SCISDIST)
                    {
                        _t1 = (SCISDIST-_oyp0)/(_yp1-_oyp0); _xp1 = (_xp1-_oxp0)*_t1+_oxp0; _yp1 = SCISDIST;
//                        _nx1 = (skywalx[(i+1)&3]-skywalx[i&3])*_t1+skywalx[i&3];
//                        _ny1 = (skywaly[(i+1)&3]-skywaly[i&3])*_t1+skywaly[i&3];
                    }
                    else { _t1 = 1.f; /*_nx1 = skywalx[(i+1)&3]; _ny1 = skywaly[(i+1)&3];*/ }

                    _ryp0 = 1.f/_yp0; _ryp1 = 1.f/_yp1;

                    //Generate screen coordinates for front side of wall
                    _x0 = ghalfx*_xp0*_ryp0 + ghalfx;
                    _x1 = ghalfx*_xp1*_ryp1 + ghalfx;
                    if (_x1 <= _x0) continue;
                    if ((_x0 >= x1) || (x0 >= _x1)) continue;

                    _ryp0 *= gyxscale; _ryp1 *= gyxscale;

                    _cy0 = -8192.f*_ryp0 + ghoriz;
                    _fy0 =  8192.f*_ryp0 + ghoriz;
                    _cy1 = -8192.f*_ryp1 + ghoriz;
                    _fy1 =  8192.f*_ryp1 + ghoriz;

                    _ox0 = _x0; _ox1 = _x1;

                    //Make sure: x0<=_x0<_x1<=_x1
                    nfy0 = fy0; nfy1 = fy1;
                    if (_x0 < x0)
                    {
                        t = (x0-_x0)/(_x1-_x0);
                        _cy0 += (_cy1-_cy0)*t;
                        _fy0 += (_fy1-_fy0)*t;
                        _x0 = x0;
                    }
                    else if (_x0 > x0) nfy0 += (_x0-x0)*(fy1-fy0)/(x1-x0);
                    if (_x1 > x1)
                    {
                        t = (x1-_x1)/(_x1-_x0);
                        _cy1 += (_cy1-_cy0)*t;
                        _fy1 += (_fy1-_fy0)*t;
                        _x1 = x1;
                    }
                    else if (_x1 < x1) nfy1 += (_x1-x1)*(fy1-fy0)/(x1-x0);

                    //   (skybox floor)
                    //(_x0,_fy0)-(_x1,_fy1)
                    //   (skybox wall)
                    //(_x0,_cy0)-(_x1,_cy1)
                    //   (skybox ceiling)
                    //(_x0,nfy0)-(_x1,nfy1)

                    //ceiling of skybox
                    ft[0] = 512/16; ft[1] = 512/-16;
                    ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                    ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                    gdx = 0;
                    gdy = gxyaspect*(1.f/4194304.f);
                    gdo = -ghoriz*gdy;
                    gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                    gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                    guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                    guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                    guo += (double)(ft[2]-gux)*ghalfx;
                    gvo -= (double)(ft[3]+gvx)*ghalfx;
                    gvx = -gvx; gvy = -gvy; gvo = -gvo; //y-flip skybox floor
#ifdef USE_OPENGL
                    drawingskybox = 6; //ceiling/5th texture/index 4 of skybox
#endif
                    if ((_fy0 > nfy0) && (_fy1 > nfy1)) domost(_x0,_fy0,_x1,_fy1);
                    else if ((_fy0 > nfy0) != (_fy1 > nfy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_cy0)-(_x1,_cy1)
                        //                            (_x0,nfy0)-(_x1,nfy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _cy0 + (_cy1-_cy0)*t
                        //oy = nfy0 + (nfy1-nfy0)*t
                        t = (_fy0-nfy0)/(nfy1-nfy0-_fy1+_fy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _fy0 + (_fy1-_fy0)*t;
                        if (nfy0 > _fy0) { domost(_x0,nfy0,ox,oy); domost(ox,oy,_x1,_fy1); }
                        else { domost(_x0,_fy0,ox,oy); domost(ox,oy,_x1,nfy1); }
                    }
                    else domost(_x0,nfy0,_x1,nfy1);

                    //wall of skybox
#ifdef USE_OPENGL
                    drawingskybox = i+1; //i+1th texture/index i of skybox
#endif
                    gdx = (_ryp0-_ryp1)*gxyaspect*(1.f/512.f) / (_ox0-_ox1);
                    gdy = 0;
                    gdo = _ryp0*gxyaspect*(1.f/512.f) - gdx*_ox0;
                    gux = (_t0*_ryp0 - _t1*_ryp1)*gxyaspect*(64.f/512.f) / (_ox0-_ox1);
                    guo = _t0*_ryp0*gxyaspect*(64.f/512.f) - gux*_ox0;
                    guy = 0;
                    _t0 = -8192.0*_ryp0 + ghoriz;
                    _t1 = -8192.0*_ryp1 + ghoriz;
                    t = ((gdx*_ox0 + gdo)*8.f) / ((_ox1-_ox0) * _ryp0 * 2048.f);
                    gvx = (_t0-_t1)*t;
                    gvy = (_ox1-_ox0)*t;
                    gvo = -gvx*_ox0 - gvy*_t0;
                    if ((_cy0 > nfy0) && (_cy1 > nfy1)) domost(_x0,_cy0,_x1,_cy1);
                    else if ((_cy0 > nfy0) != (_cy1 > nfy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_fy0)-(_x1,_fy1)
                        //                            (_x0,nfy0)-(_x1,nfy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _fy0 + (_fy1-_fy0)*t
                        //oy = nfy0 + (nfy1-nfy0)*t
                        t = (_cy0-nfy0)/(nfy1-nfy0-_cy1+_cy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _cy0 + (_cy1-_cy0)*t;
                        if (nfy0 > _cy0) { domost(_x0,nfy0,ox,oy); domost(ox,oy,_x1,_cy1); }
                        else { domost(_x0,_cy0,ox,oy); domost(ox,oy,_x1,nfy1); }
                    }
                    else domost(_x0,nfy0,_x1,nfy1);
                }

                //Floor of skybox
#ifdef USE_OPENGL
                drawingskybox = 5; //floor/6th texture/index 5 of skybox
#endif
                ft[0] = 512/16; ft[1] = -512/-16;
                ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                gdx = 0;
                gdy = gxyaspect*(-1.f/4194304.f);
                gdo = -ghoriz*gdy;
                gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                guo += (double)(ft[2]-gux)*ghalfx;
                gvo -= (double)(ft[3]+gvx)*ghalfx;
                domost(x0,fy0,x1,fy1);

                skyclamphack = 0;
#ifdef USE_OPENGL
                drawingskybox = 0;
#endif
            }
#ifdef USE_OPENGL
            if (getrendermode() >= REND_POLYMOST)
            {
                skyclamphack = 0;
                if (!nofog)
                    bglEnable(GL_FOG);
            }
#endif
        }

        globalpicnum = sec->ceilingpicnum; globalshade = sec->ceilingshade; globalpal = (int32_t)((uint8_t)sec->ceilingpal);
        globalorientation = sec->ceilingstat;
        globvis = globalcisibility;
        if (sector[sectnum].visibility != 0) globvis = mulscale4(globvis, (uint8_t)(sector[sectnum].visibility+16));

        DO_TILE_ANIM(globalpicnum, sectnum);

        // multi-psky stuff
        dapskyoff = zeropskyoff;
        dapskybits = pskybits;

        for (i=0; i<pskynummultis; i++)
        {
            if (globalpicnum == pskymultilist[i])
            {
                dapskybits = pskymultibits[i];
                dapskyoff = pskymultioff[i];
                break;
            }
        }
        //

        global_cf_shade = sec->ceilingshade, global_cf_pal = sec->ceilingpal; global_cf_z = sec->ceilingz;  // REFACT
        global_cf_xpanning = sec->ceilingxpanning; global_cf_ypanning = sec->ceilingypanning, global_cf_heinum = sec->ceilingheinum;
        global_getzofslope_func = &getceilzofslope;

        if (!(globalorientation&1))
        {
#ifdef YAX_ENABLE
            if (globalposz >= sec->ceilingz || yax_getbunch(sectnum, YAX_CEILING) < 0 || yax_getnextwall(wallnum, YAX_CEILING) >= 0)
#endif
                polymost_internal_nonparallaxed(nx0, ny0, nx1, ny1, ryp0, ryp1, x0, x1, cy0, cy1, 0, sectnum);
        }
        else if ((nextsectnum < 0) || (!(sector[nextsectnum].ceilingstat&1)))
        {
#ifdef USE_OPENGL
            if (getrendermode() >= REND_POLYMOST)
            {
                calc_and_apply_fog_factor(sec->ceilingpicnum, sec->ceilingshade, sec->visibility, sec->ceilingpal, 0.005);

                //Use clamping for tiled sky textures
                for (i=(1<<dapskybits)-1; i>0; i--)
                    if (dapskyoff[i] != dapskyoff[i-1])
                        { skyclamphack = r_parallaxskyclamping; break; }
            }
#endif
            //Parallaxing sky...
            if (bpp == 8 || !usehightile || !hicfindsubst(globalpicnum,globalpal,1))
            {
                //Render for parallaxtype == 0 / paper-sky
                dd[0] = (float)xdimen*.0000001; //Adjust sky depth based on screen size!
                t = (double)((1<<(picsiz[globalpicnum]&15))<<dapskybits);
                vv[1] = dd[0]*((double)xdimscale*(double)viewingrange)/(65536.0*65536.0);
                vv[0] = dd[0]*((double)((tilesizy[globalpicnum]>>1)+parallaxyoffs)) - vv[1]*ghoriz;
                i = (1<<(picsiz[globalpicnum]>>4)); if (i != tilesizy[globalpicnum]) i += i;

                //Hack to draw black rectangle below sky when looking down...
                gdx = 0; gdy = gxyaspect / -262144.0; gdo = -ghoriz*gdy;
                gux = 0; guy = 0; guo = 0;
                gvx = 0; gvy = 0; gvo = 0;
                oy = -vv[0]/vv[1];

                if ((oy < cy0) && (oy < cy1)) domost(x1,oy,x0,oy);
                else if ((oy < cy0) != (oy < cy1))
                {
                    /*         cy1        cy0
                    //        /              \
                    //oy----------      oy---------
                    //    /                   \
                    //  cy0                     cy1
                    */
                    ox = (oy-cy0)*(x1-x0)/(cy1-cy0) + x0;
                    if (oy < cy0) { domost(ox,oy,x0,oy); domost(x1,cy1,ox,oy); }
                    else { domost(ox,oy,x0,cy0); domost(x1,oy,ox,oy); }
                }
                else domost(x1,cy1,x0,cy0);

                if (r_parallaxskypanning)
                    vv[0] += dd[0]*((double)sec->ceilingypanning)*((double)i)/256.0;

                gdx = 0; gdy = 0; gdo = dd[0];
                gux = gdo*(t*((double)xdimscale)*((double)yxaspect)*((double)viewingrange))/(16384.0*65536.0*65536.0*5.0*1024.0);
                guy = 0; //guo calculated later
                gvx = 0; gvy = vv[1]; gvo = vv[0];

                i = globalpicnum; r = (cy1-cy0)/(x1-x0); //slope of line
                oy = ((double)viewingrange)/(ghalfx*256.0); oz = 1/oy;

                y = ((((int32_t)((x0-ghalfx)*oy))+globalang)>>(11-dapskybits));
                fx = x0;
                do
                {
                    globalpicnum = dapskyoff[y&((1<<dapskybits)-1)]+i;
                    guo = gdo*(t*((double)(globalang-(y<<(11-dapskybits))))/2048.0 + (double)((r_parallaxskypanning)?sec->ceilingxpanning:0)) - gux*ghalfx;
                    y++;
                    ox = fx; fx = ((double)((y<<(11-dapskybits))-globalang))*oz+ghalfx;
                    if (fx > x1) { fx = x1; i = -1; }
                    pow2xsplit = 0; domost(fx,(fx-x0)*r+cy0,ox,(ox-x0)*r+cy0); //ceil
                }
                while (i >= 0);
            }
            else
            {
                //Skybox code for parallax ceiling!
                double _xp0, _yp0, _xp1, _yp1, _oxp0, _oyp0, _t0, _t1; // _nx0, _ny0, _nx1, _ny1;
                double _ryp0, _ryp1, _x0, _x1, _cy0, _fy0, _cy1, _fy1, _ox0, _ox1;
                double ncy0, ncy1;
                int32_t skywalx[4] = {-512,512,512,-512}, skywaly[4] = {-512,-512,512,512};

                pow2xsplit = 0;
                skyclamphack = 1;

                for (i=0; i<4; i++)
                {
                    x = skywalx[i&3]; y = skywaly[i&3];
                    _xp0 = (double)y*gcosang  - (double)x*gsinang;
                    _yp0 = (double)x*gcosang2 + (double)y*gsinang2;
                    x = skywalx[(i+1)&3]; y = skywaly[(i+1)&3];
                    _xp1 = (double)y*gcosang  - (double)x*gsinang;
                    _yp1 = (double)x*gcosang2 + (double)y*gsinang2;

                    _oxp0 = _xp0; _oyp0 = _yp0;

                    //Clip to close parallel-screen plane
                    if (_yp0 < SCISDIST)
                    {
                        if (_yp1 < SCISDIST) continue;
                        _t0 = (SCISDIST-_yp0)/(_yp1-_yp0); _xp0 = (_xp1-_xp0)*_t0+_xp0; _yp0 = SCISDIST;
//                        _nx0 = (skywalx[(i+1)&3]-skywalx[i&3])*_t0+skywalx[i&3];
//                        _ny0 = (skywaly[(i+1)&3]-skywaly[i&3])*_t0+skywaly[i&3];
                    }
                    else { _t0 = 0.f; /*_nx0 = skywalx[i&3]; _ny0 = skywaly[i&3];*/ }
                    if (_yp1 < SCISDIST)
                    {
                        _t1 = (SCISDIST-_oyp0)/(_yp1-_oyp0); _xp1 = (_xp1-_oxp0)*_t1+_oxp0; _yp1 = SCISDIST;
//                        _nx1 = (skywalx[(i+1)&3]-skywalx[i&3])*_t1+skywalx[i&3];
//                        _ny1 = (skywaly[(i+1)&3]-skywaly[i&3])*_t1+skywaly[i&3];
                    }
                    else { _t1 = 1.f; /*_nx1 = skywalx[(i+1)&3]; _ny1 = skywaly[(i+1)&3];*/ }

                    _ryp0 = 1.f/_yp0; _ryp1 = 1.f/_yp1;

                    //Generate screen coordinates for front side of wall
                    _x0 = ghalfx*_xp0*_ryp0 + ghalfx;
                    _x1 = ghalfx*_xp1*_ryp1 + ghalfx;
                    if (_x1 <= _x0) continue;
                    if ((_x0 >= x1) || (x0 >= _x1)) continue;

                    _ryp0 *= gyxscale; _ryp1 *= gyxscale;

                    _cy0 = -8192.f*_ryp0 + ghoriz;
                    _fy0 =  8192.f*_ryp0 + ghoriz;
                    _cy1 = -8192.f*_ryp1 + ghoriz;
                    _fy1 =  8192.f*_ryp1 + ghoriz;

                    _ox0 = _x0; _ox1 = _x1;

                    //Make sure: x0<=_x0<_x1<=_x1
                    ncy0 = cy0; ncy1 = cy1;
                    if (_x0 < x0)
                    {
                        t = (x0-_x0)/(_x1-_x0);
                        _cy0 += (_cy1-_cy0)*t;
                        _fy0 += (_fy1-_fy0)*t;
                        _x0 = x0;
                    }
                    else if (_x0 > x0) ncy0 += (_x0-x0)*(cy1-cy0)/(x1-x0);
                    if (_x1 > x1)
                    {
                        t = (x1-_x1)/(_x1-_x0);
                        _cy1 += (_cy1-_cy0)*t;
                        _fy1 += (_fy1-_fy0)*t;
                        _x1 = x1;
                    }
                    else if (_x1 < x1) ncy1 += (_x1-x1)*(cy1-cy0)/(x1-x0);

                    //   (skybox ceiling)
                    //(_x0,_cy0)-(_x1,_cy1)
                    //   (skybox wall)
                    //(_x0,_fy0)-(_x1,_fy1)
                    //   (skybox floor)
                    //(_x0,ncy0)-(_x1,ncy1)

                    //ceiling of skybox
#ifdef USE_OPENGL
                    drawingskybox = 5; //ceiling/5th texture/index 4 of skybox
#endif
                    ft[0] = 512/16; ft[1] = -512/-16;
                    ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                    ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                    gdx = 0;
                    gdy = gxyaspect*-(1.f/4194304.f);
                    gdo = -ghoriz*gdy;
                    gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                    gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                    guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                    guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                    guo += (double)(ft[2]-gux)*ghalfx;
                    gvo -= (double)(ft[3]+gvx)*ghalfx;
                    if ((_cy0 < ncy0) && (_cy1 < ncy1)) domost(_x1,_cy1,_x0,_cy0);
                    else if ((_cy0 < ncy0) != (_cy1 < ncy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_cy0)-(_x1,_cy1)
                        //                            (_x0,ncy0)-(_x1,ncy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _cy0 + (_cy1-_cy0)*t
                        //oy = ncy0 + (ncy1-ncy0)*t
                        t = (_cy0-ncy0)/(ncy1-ncy0-_cy1+_cy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _cy0 + (_cy1-_cy0)*t;
                        if (ncy0 < _cy0) { domost(ox,oy,_x0,ncy0); domost(_x1,_cy1,ox,oy); }
                        else { domost(ox,oy,_x0,_cy0); domost(_x1,ncy1,ox,oy); }
                    }
                    else domost(_x1,ncy1,_x0,ncy0);

                    //wall of skybox
#ifdef USE_OPENGL
                    drawingskybox = i+1; //i+1th texture/index i of skybox
#endif
                    gdx = (_ryp0-_ryp1)*gxyaspect*(1.f/512.f) / (_ox0-_ox1);
                    gdy = 0;
                    gdo = _ryp0*gxyaspect*(1.f/512.f) - gdx*_ox0;
                    gux = (_t0*_ryp0 - _t1*_ryp1)*gxyaspect*(64.f/512.f) / (_ox0-_ox1);
                    guo = _t0*_ryp0*gxyaspect*(64.f/512.f) - gux*_ox0;
                    guy = 0;
                    _t0 = -8192.0*_ryp0 + ghoriz;
                    _t1 = -8192.0*_ryp1 + ghoriz;
                    t = ((gdx*_ox0 + gdo)*8.f) / ((_ox1-_ox0) * _ryp0 * 2048.f);
                    gvx = (_t0-_t1)*t;
                    gvy = (_ox1-_ox0)*t;
                    gvo = -gvx*_ox0 - gvy*_t0;
                    if ((_fy0 < ncy0) && (_fy1 < ncy1)) domost(_x1,_fy1,_x0,_fy0);
                    else if ((_fy0 < ncy0) != (_fy1 < ncy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_fy0)-(_x1,_fy1)
                        //                            (_x0,ncy0)-(_x1,ncy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _fy0 + (_fy1-_fy0)*t
                        //oy = ncy0 + (ncy1-ncy0)*t
                        t = (_fy0-ncy0)/(ncy1-ncy0-_fy1+_fy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _fy0 + (_fy1-_fy0)*t;
                        if (ncy0 < _fy0) { domost(ox,oy,_x0,ncy0); domost(_x1,_fy1,ox,oy); }
                        else { domost(ox,oy,_x0,_fy0); domost(_x1,ncy1,ox,oy); }
                    }
                    else domost(_x1,ncy1,_x0,ncy0);
                }

                //Floor of skybox
#ifdef USE_OPENGL
                drawingskybox = 6; //floor/6th texture/index 5 of skybox
#endif
                ft[0] = 512/16; ft[1] = 512/-16;
                ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                gdx = 0;
                gdy = gxyaspect*(1.f/4194304.f);
                gdo = -ghoriz*gdy;
                gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                guo += (double)(ft[2]-gux)*ghalfx;
                gvo -= (double)(ft[3]+gvx)*ghalfx;
                gvx = -gvx; gvy = -gvy; gvo = -gvo; //y-flip skybox floor
                domost(x1,cy1,x0,cy0);

                skyclamphack = 0;
#ifdef USE_OPENGL
                drawingskybox = 0;
#endif
            }
#ifdef USE_OPENGL
            if (getrendermode() >= REND_POLYMOST)
            {
                skyclamphack = 0;
                if (!nofog)
                    bglEnable(GL_FOG);
            }
#endif
        }

        //(x0,cy0) == (u=             0,v=0,d=)
        //(x1,cy0) == (u=wal->xrepeat*8,v=0)
        //(x0,fy0) == (u=             0,v=v)
        //             u = (gux*sx + guy*sy + guo) / (gdx*sx + gdy*sy + gdo)
        //             v = (gvx*sx + gvy*sy + gvo) / (gdx*sx + gdy*sy + gdo)
        //             0 = (gux*x0 + guy*cy0 + guo) / (gdx*x0 + gdy*cy0 + gdo)
        //wal->xrepeat*8 = (gux*x1 + guy*cy0 + guo) / (gdx*x1 + gdy*cy0 + gdo)
        //             0 = (gvx*x0 + gvy*cy0 + gvo) / (gdx*x0 + gdy*cy0 + gdo)
        //             v = (gvx*x0 + gvy*fy0 + gvo) / (gdx*x0 + gdy*fy0 + gdo)
        //sx = x0, u = t0*wal->xrepeat*8, d = yp0;
        //sx = x1, u = t1*wal->xrepeat*8, d = yp1;
        //d = gdx*sx + gdo
        //u = (gux*sx + guo) / (gdx*sx + gdo)
        //yp0 = gdx*x0 + gdo
        //yp1 = gdx*x1 + gdo
        //t0*wal->xrepeat*8 = (gux*x0 + guo) / (gdx*x0 + gdo)
        //t1*wal->xrepeat*8 = (gux*x1 + guo) / (gdx*x1 + gdo)
        //gdx*x0 + gdo = yp0
        //gdx*x1 + gdo = yp1
        gdx = (ryp0-ryp1)*gxyaspect / (x0-x1);
        gdy = 0;
        gdo = ryp0*gxyaspect - gdx*x0;

        //gux*x0 + guo = t0*wal->xrepeat*8*yp0
        //gux*x1 + guo = t1*wal->xrepeat*8*yp1
        gux = (t0*ryp0 - t1*ryp1)*gxyaspect*(float)wal->xrepeat*8.f / (x0-x1);
        guo = t0*ryp0*gxyaspect*(float)wal->xrepeat*8.f - gux*x0;
        guo += (float)wal->xpanning*gdo;
        gux += (float)wal->xpanning*gdx;
        guy = 0;
        //Derivation for u:
        //   (gvx*x0 + gvy*cy0 + gvo) / (gdx*x0 + gdy*cy0 + gdo) = 0
        //   (gvx*x1 + gvy*cy1 + gvo) / (gdx*x1 + gdy*cy1 + gdo) = 0
        //   (gvx*x0 + gvy*fy0 + gvo) / (gdx*x0 + gdy*fy0 + gdo) = v
        //   (gvx*x1 + gvy*fy1 + gvo) / (gdx*x1 + gdy*fy1 + gdo) = v
        //   (gvx*x0 + gvy*cy0 + gvo*1) = 0
        //   (gvx*x1 + gvy*cy1 + gvo*1) = 0
        //   (gvx*x0 + gvy*fy0 + gvo*1) = t
        ogux = gux; oguy = guy; oguo = guo;

        if (nextsectnum >= 0)
        {
            getzsofslope(nextsectnum,(int32_t)nx0,(int32_t)ny0,&cz,&fz);
            ocy0 = ((float)(cz-globalposz))*ryp0 + ghoriz;
            ofy0 = ((float)(fz-globalposz))*ryp0 + ghoriz;
            getzsofslope(nextsectnum,(int32_t)nx1,(int32_t)ny1,&cz,&fz);
            ocy1 = ((float)(cz-globalposz))*ryp1 + ghoriz;
            ofy1 = ((float)(fz-globalposz))*ryp1 + ghoriz;

            if ((wal->cstat&48) == 16) maskwall[maskwallcnt++] = z;

            if (((cy0 < ocy0) || (cy1 < ocy1)) && (!((sec->ceilingstat&sector[nextsectnum].ceilingstat)&1)))
            {
                globalpicnum = wal->picnum; globalshade = wal->shade; globalpal = (int32_t)((uint8_t)wal->pal);
                globvis = globalvisibility;
                if (sector[sectnum].visibility != 0) globvis = mulscale4(globvis, (uint8_t)(sector[sectnum].visibility+16));

                DO_TILE_ANIM(globalpicnum, wallnum+16384);

                if (!(wal->cstat&4)) i = sector[nextsectnum].ceilingz; else i = sec->ceilingz;

                // over
                calc_ypanning(i, ryp0, ryp1, x0, x1, wal->ypanning, wal->yrepeat, wal->cstat&4);

                if (wal->cstat&8) //xflip
                {
                    t = (float)(wal->xrepeat*8 + wal->xpanning*2);
                    gux = gdx*t - gux;
                    guy = gdy*t - guy;
                    guo = gdo*t - guo;
                }
                if (wal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip

                calc_and_apply_fog(wal->picnum, wal->shade, sec->visibility, sec->floorpal);

                pow2xsplit = 1; domost(x1,ocy1,x0,ocy0);
                if (wal->cstat&8) { gux = ogux; guy = oguy; guo = oguo; }
            }
            if (((ofy0 < fy0) || (ofy1 < fy1)) && (!((sec->floorstat&sector[nextsectnum].floorstat)&1)))
            {
                if (!(wal->cstat&2)) nwal = wal;
                else
                {
                    nwal = &wall[wal->nextwall];
                    guo += (float)(nwal->xpanning-wal->xpanning)*gdo;
                    gux += (float)(nwal->xpanning-wal->xpanning)*gdx;
                    guy += (float)(nwal->xpanning-wal->xpanning)*gdy;
                }
                globalpicnum = nwal->picnum; globalshade = nwal->shade; globalpal = (int32_t)((uint8_t)nwal->pal);
                globvis = globalvisibility;
                if (sector[sectnum].visibility != 0) globvis = mulscale4(globvis, (uint8_t)(sector[sectnum].visibility+16));

                DO_TILE_ANIM(globalpicnum, wallnum+16384);

                if (!(nwal->cstat&4)) i = sector[nextsectnum].floorz; else i = sec->ceilingz;

                // under
                calc_ypanning(i, ryp0, ryp1, x0, x1, nwal->ypanning, wal->yrepeat, !(nwal->cstat&4));

                if (wal->cstat&8) //xflip
                {
                    t = (float)(wal->xrepeat*8 + nwal->xpanning*2);
                    gux = gdx*t - gux;
                    guy = gdy*t - guy;
                    guo = gdo*t - guo;
                }
                if (nwal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip

                calc_and_apply_fog(nwal->picnum, nwal->shade, sec->visibility, sec->floorpal);

                pow2xsplit = 1; domost(x0,ofy0,x1,ofy1);
                if (wal->cstat&(2+8)) { guo = oguo; gux = ogux; guy = oguy; }
            }
        }

        if ((nextsectnum < 0) || (wal->cstat&32))   //White/1-way wall
        {
            if (nextsectnum < 0) globalpicnum = wal->picnum; else globalpicnum = wal->overpicnum;
            globalshade = wal->shade; globalpal = (int32_t)((uint8_t)wal->pal);
            globvis = globalvisibility;
            if (sector[sectnum].visibility != 0) globvis = mulscale4(globvis, (uint8_t)(sector[sectnum].visibility+16));

            DO_TILE_ANIM(globalpicnum, wallnum+16384);

            if (nextsectnum >= 0) { if (!(wal->cstat&4)) i = nextsec->ceilingz; else i = sec->ceilingz; }
            else { if (!(wal->cstat&4)) i = sec->ceilingz;     else i = sec->floorz; }

            // white
            calc_ypanning(i, ryp0, ryp1, x0, x1, wal->ypanning, wal->yrepeat, !(wal->cstat&4));

            if (wal->cstat&8) //xflip
            {
                t = (float)(wal->xrepeat*8 + wal->xpanning*2);
                gux = gdx*t - gux;
                guy = gdy*t - guy;
                guo = gdo*t - guo;
            }
            if (wal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip

            calc_and_apply_fog(wal->picnum, wal->shade, sec->visibility, sec->floorpal);

            pow2xsplit = 1; domost(x0,-10000,x1,-10000);
        }

        if (nextsectnum >= 0)
            if ((!(gotsector[nextsectnum>>3]&pow2char[nextsectnum&7])) && (testvisiblemost(x0,x1)))
                polymost_scansector(nextsectnum);
    }
}

static int32_t polymost_bunchfront(int32_t b1, int32_t b2)
{
    double x1b1, x1b2, x2b1, x2b2;
    int32_t b1f, b2f, i;

    b1f = bunchfirst[b1]; x1b1 = dxb1[b1f]; x2b2 = dxb2[bunchlast[b2]]; if (x1b1 >= x2b2) return(-1);
    b2f = bunchfirst[b2]; x1b2 = dxb1[b2f]; x2b1 = dxb2[bunchlast[b1]]; if (x1b2 >= x2b1) return(-1);

    if (x1b1 >= x1b2)
    {
        for (i=b2f; dxb2[i]<=x1b1; i=p2[i]);
        return(wallfront(b1f,i));
    }
    for (i=b1f; dxb2[i]<=x1b2; i=p2[i]);
    return(wallfront(i,b2f));
}

void polymost_scansector(int32_t sectnum)
{
    double d, xp1, yp1, xp2, yp2;
    walltype *wal, *wal2;
    spritetype *spr;
    int32_t z, zz, startwall, endwall, numscansbefore, scanfirst, bunchfrst, nextsectnum;
    int32_t xs, ys, x1, y1, x2, y2;

    if (sectnum < 0) return;

    sectorborder[0] = sectnum, sectorbordercnt = 1;
    do
    {
        sectnum = sectorborder[--sectorbordercnt];

        for (z=headspritesect[sectnum]; z>=0; z=nextspritesect[z])
        {
            spr = &sprite[z];
            if ((((spr->cstat&0x8000) == 0) || (showinvisibility)) &&
                    (spr->xrepeat > 0) && (spr->yrepeat > 0))
            {
                xs = spr->x-globalposx; ys = spr->y-globalposy;
                if ((spr->cstat&48) || (xs*gcosang+ys*gsinang > 0) || (usemodels && tile2model[spr->picnum].modelid>=0))
                {
                    if ((spr->cstat&(64+48))!=(64+16) || dmulscale6(sintable[(spr->ang+512)&2047],-xs, sintable[spr->ang&2047],-ys) > 0)
                        if (engine_addtsprite(z, sectnum))
                            break;
                }
            }
        }

        gotsector[sectnum>>3] |= pow2char[sectnum&7];

        bunchfrst = numbunches;
        numscansbefore = numscans;

        startwall = sector[sectnum].wallptr; endwall = sector[sectnum].wallnum+startwall;
        scanfirst = numscans;
        xp2 = 0; yp2 = 0;
        for (z=startwall,wal=&wall[z]; z<endwall; z++,wal++)
        {
            wal2 = &wall[wal->point2];
            x1 = wal->x-globalposx; y1 = wal->y-globalposy;
            x2 = wal2->x-globalposx; y2 = wal2->y-globalposy;

            nextsectnum = wal->nextsector; //Scan close sectors
#ifdef YAX_ENABLE
            if (yax_nomaskpass==0 || !yax_isislandwall(z, !yax_globalcf) || (yax_nomaskdidit=1, 0))
#endif
            if ((nextsectnum >= 0) && (!(wal->cstat&32)) && (!(gotsector[nextsectnum>>3]&pow2char[nextsectnum&7])))
            {
                d = (double)x1*(double)y2 - (double)x2*(double)y1; xp1 = (double)(x2-x1); yp1 = (double)(y2-y1);
                if (d*d <= (xp1*xp1 + yp1*yp1)*(SCISDIST*SCISDIST*260.0))
                    sectorborder[sectorbordercnt++] = nextsectnum;
            }

            if ((z == startwall) || (wall[z-1].point2 != z))
            {
                xp1 = ((double)y1*(double)cosglobalang             - (double)x1*(double)singlobalang)/64.0;
                yp1 = ((double)x1*(double)cosviewingrangeglobalang + (double)y1*(double)sinviewingrangeglobalang)/64.0;
            }
            else { xp1 = xp2; yp1 = yp2; }
            xp2 = ((double)y2*(double)cosglobalang             - (double)x2*(double)singlobalang)/64.0;
            yp2 = ((double)x2*(double)cosviewingrangeglobalang + (double)y2*(double)sinviewingrangeglobalang)/64.0;
            if ((yp1 >= SCISDIST) || (yp2 >= SCISDIST))
                if ((double)xp1*(double)yp2 < (double)xp2*(double)yp1) //if wall is facing you...
                {
                    if (yp1 >= SCISDIST)
                        dxb1[numscans] = (double)xp1*ghalfx/(double)yp1 + ghalfx;
                    else dxb1[numscans] = -1e32;

                    if (yp2 >= SCISDIST)
                        dxb2[numscans] = (double)xp2*ghalfx/(double)yp2 + ghalfx;
                    else dxb2[numscans] = 1e32;

                    if (dxb1[numscans] < dxb2[numscans])
                        { thesector[numscans] = sectnum; thewall[numscans] = z; p2[numscans] = numscans+1; numscans++; }
                }

            if ((wall[z].point2 < z) && (scanfirst < numscans))
                { p2[numscans-1] = scanfirst; scanfirst = numscans; }
        }

        for (z=numscansbefore; z<numscans; z++)
            if ((wall[thewall[z]].point2 != thewall[p2[z]]) || (dxb2[z] > dxb1[p2[z]]))
            {
                bunchfirst[numbunches++] = p2[z]; p2[z] = -1;
#ifdef YAX_ENABLE
                if (scansector_retfast)
                    return;
#endif
            }

        for (z=bunchfrst; z<numbunches; z++)
        {
            for (zz=bunchfirst[z]; p2[zz]>=0; zz=p2[zz]);
            bunchlast[z] = zz;
        }
    }
    while (sectorbordercnt > 0);
}

void polymost_drawrooms()
{
    int32_t i, j, n, n2, closest;
    double ox, oy, oz, ox2, oy2, oz2, r, px[6], py[6], pz[6], px2[6], py2[6], pz2[6], sx[6], sy[6];

    if (getrendermode() == REND_CLASSIC) return;

    begindrawing();
    frameoffset = frameplace + windowy1*bytesperline + windowx1;

#ifdef USE_OPENGL
    if (getrendermode() >= REND_POLYMOST)
    {
        resizeglcheck();
#ifdef YAX_ENABLE
        if (numyaxbunches==0)
#endif
            if (editstatus)
                bglClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

        bglDisable(GL_BLEND);
        bglEnable(GL_TEXTURE_2D);
        //bglTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE); //default anyway
        bglEnable(GL_DEPTH_TEST);
        bglDepthFunc(GL_ALWAYS); //NEVER,LESS,(,L)EQUAL,GREATER,(NOT,G)EQUAL,ALWAYS

        //bglPolygonOffset(1,1); //Supposed to make sprites pasted on walls or floors not disappear
        bglDepthRange(0.00001,1.0); //<- this is more widely supported than glPolygonOffset

        //Enable this for OpenGL red-blue glasses mode :)
        if (glredbluemode)
        {
            static int32_t grbfcnt = 0; grbfcnt++;
            if (redblueclearcnt < numpages) { redblueclearcnt++; bglColorMask(1,1,1,1); bglClear(GL_COLOR_BUFFER_BIT); }
            if (grbfcnt&1)
            {
                bglViewport(windowx1-16,yres-(windowy2+1),windowx2-(windowx1-16)+1,windowy2-windowy1+1);
                bglColorMask(1,0,0,1);
                globalposx += singlobalang/1024;
                globalposy -= cosglobalang/1024;
            }
            else
            {
                bglViewport(windowx1,yres-(windowy2+1),windowx2+16-windowx1+1,windowy2-windowy1+1);
                bglColorMask(0,1,1,1);
                globalposx -= singlobalang/1024;
                globalposy += cosglobalang/1024;
            }
        }
    }
#endif

    //Polymost supports true look up/down :) Here, we convert horizon to angle.
    //gchang&gshang are cos&sin of this angle (respectively)
    gyxscale = ((double)xdimenscale)/131072.0;
    gxyaspect = ((double)xyaspect*(double)viewingrange)*(5.0/(65536.0*262144.0));
    gviewxrange = ((double)viewingrange)*((double)xdimen)/(32768.0*1024.0);
    gcosang = ((double)cosglobalang)/262144.0;
    gsinang = ((double)singlobalang)/262144.0;
    gcosang2 = gcosang*((double)viewingrange)/65536.0;
    gsinang2 = gsinang*((double)viewingrange)/65536.0;
    ghalfx = (double)halfxdimen; grhalfxdown10 = 1.0/(((double)ghalfx)*1024);
    ghoriz = (double)globalhoriz;

    gvisibility = ((float)globalvisibility)*FOGSCALE;

    //global cos/sin height angle
    r = (double)((ydimen>>1)-ghoriz);
    gshang = r/sqrt(r*r+ghalfx*ghalfx);
    gchang = sqrt(1.0-gshang*gshang);
    ghoriz = (double)(ydimen>>1);

    //global cos/sin tilt angle
    gctang = cos(gtang);
    gstang = sin(gtang);
    if (fabs(gstang) < .001) //This hack avoids nasty precision bugs in domost()
        { gstang = 0; if (gctang > 0) gctang = 1.0; else gctang = -1.0; }

    if (inpreparemirror)
        gstang = -gstang;

    //Generate viewport trapezoid (for handling screen up/down)
    px[0] = px[3] = 0-1; px[1] = px[2] = windowx2+1-windowx1+2;
    py[0] = py[1] = 0-1; py[2] = py[3] = windowy2+1-windowy1+2; n = 4;
    for (i=0; i<n; i++)
    {
        ox = px[i]-ghalfx; oy = py[i]-ghoriz; oz = ghalfx;

        //Tilt rotation (backwards)
        ox2 = ox*gctang + oy*gstang;
        oy2 = oy*gctang - ox*gstang;
        oz2 = oz;

        //Up/down rotation (backwards)
        px[i] = ox2;
        py[i] = oy2*gchang + oz2*gshang;
        pz[i] = oz2*gchang - oy2*gshang;
    }

    //Clip to SCISDIST plane
    n2 = 0;
    for (i=0; i<n; i++)
    {
        j = i+1; if (j >= n) j = 0;
        if (pz[i] >= SCISDIST) { px2[n2] = px[i]; py2[n2] = py[i]; pz2[n2] = pz[i]; n2++; }
        if ((pz[i] >= SCISDIST) != (pz[j] >= SCISDIST))
        {
            r = (SCISDIST-pz[i])/(pz[j]-pz[i]);
            px2[n2] = (px[j]-px[i])*r + px[i];
            py2[n2] = (py[j]-py[i])*r + py[i];
            pz2[n2] = SCISDIST; n2++;
        }
    }
    if (n2 < 3) { enddrawing(); return; }
    for (i=0; i<n2; i++)
    {
        r = ghalfx / pz2[i];
        sx[i] = px2[i]*r + ghalfx;
        sy[i] = py2[i]*r + ghoriz;
    }
    initmosts(sx,sy,n2);

    if (searchit == 2)
    {
        int32_t vx, vy, vz;
        int32_t cz, fz;
        hitdata_t hit;
        vec3_t vect;

        const float ratio = get_projhack_ratio();

        ox2 = (searchx-ghalfx)/ratio;
        oy2 = (searchy-ghoriz)/ratio;  // ghoriz is (ydimen>>1) here
        oz2 = ghalfx;

        //Tilt rotation
        ox = ox2*gctang + oy2*gstang;
        oy = oy2*gctang - ox2*gstang;
        oz = oz2;

        //Up/down rotation
        ox2 = oz*gchang - oy*gshang;
        oy2 = ox;
        oz2 = oy*gchang + oz*gshang;

        //Standard Left/right rotation
        vx = (int32_t)(ox2*((float)cosglobalang) - oy2*((float)singlobalang));
        vy = (int32_t)(ox2*((float)singlobalang) + oy2*((float)cosglobalang));
        vz = (int32_t)(oz2*16384.0);

        vect.x = globalposx;
        vect.y = globalposy;
        vect.z = globalposz;

        hitallsprites = 1;
        hitscan((const vec3_t *)&vect,globalcursectnum, //Start position
                vx>>10,vy>>10,vz>>6,&hit,0xffff0030);

        if (hit.sect != -1) // if hitsect is -1, hitscan overflowed somewhere
        {
            getzsofslope(hit.sect,hit.pos.x,hit.pos.y,&cz,&fz);
            hitallsprites = 0;

            searchsector = hit.sect;
            if (hit.pos.z<cz) searchstat = 1;
            else if (hit.pos.z>fz) searchstat = 2;
            else if (hit.wall >= 0)
            {
                searchbottomwall = searchwall = hit.wall; searchstat = 0;
                if (wall[hit.wall].nextwall >= 0)
                {
                    int32_t cz, fz;
                    getzsofslope(wall[hit.wall].nextsector,hit.pos.x,hit.pos.y,&cz,&fz);
                    if (hit.pos.z > fz)
                    {
                        searchisbottom = 1;
                        if (wall[hit.wall].cstat&2) //'2' bottoms of walls
                            searchbottomwall = wall[hit.wall].nextwall;
                    }
                    else
                    {
                        searchisbottom = 0;
                        if ((hit.pos.z > cz) && (wall[hit.wall].cstat&(16+32))) //masking or 1-way
                            searchstat = 4;
                    }
                }
            }
            else if (hit.sprite >= 0) { searchwall = hit.sprite; searchstat = 3; }
            else
            {
                int32_t cz, fz;
                getzsofslope(hit.sect,hit.pos.x,hit.pos.y,&cz,&fz);
                if ((hit.pos.z<<1) < cz+fz) searchstat = 1; else searchstat = 2;
                //if (vz < 0) searchstat = 1; else searchstat = 2; //Won't work for slopes :/
            }

            if (preview_mouseaim && spritesortcnt < MAXSPRITESONSCREEN)
            {
                spritetype *tsp = &tsprite[spritesortcnt];
                double dadist, x,y,z;
                Bmemcpy(tsp, &hit.pos, sizeof(vec3_t));
                x = tsp->x-globalposx; y=tsp->y-globalposy; z=(tsp->z-globalposz)/16.0;
                dadist = sqrt(x*x + y*y + z*z);
                tsp->sectnum = hit.sect;
                tsp->picnum = 2523;  // CROSSHAIR
                tsp->cstat = 128;
                tsp->owner = MAXSPRITES-1;
                tsp->xrepeat = tsp->yrepeat = min(max(1, (int32_t)(dadist*48.0/3200.0)), 255);
                sprite[tsp->owner].xoffset = sprite[tsp->owner].yoffset = 0;
                tspriteptr[spritesortcnt++] = tsp;
            }

            if ((searchstat==1 || searchstat==2) && searchsector>=0)
            {
                int32_t scrv[2] = {(vx>>12), (vy>>12)};
                int32_t scrv_r[2] = {scrv[1], -scrv[0]};
                walltype *wal = &wall[sector[searchsector].wallptr];
                uint64_t wdistsq, bestwdistsq=0x7fffffff;
                int32_t k, bestk=-1;

                for (k=0; k<sector[searchsector].wallnum; k++)
                {
                    int32_t w1[2] = {wal[k].x, wal[k].y};
                    int32_t w2[2] = {wall[wal[k].point2].x, wall[wal[k].point2].y};
                    int32_t w21[2] = {w1[0]-w2[0], w1[1]-w2[1]};
                    int32_t pw1[2] = {w1[0]-hit.pos.x, w1[1]-hit.pos.y};
                    int32_t pw2[2] = {w2[0]-hit.pos.x, w2[1]-hit.pos.y};
                    float w1d = (float)(scrv_r[0]*pw1[0] + scrv_r[1]*pw1[1]);
                    float w2d = (float)(scrv_r[0]*pw2[0] + scrv_r[1]*pw2[1]);
                    int32_t ptonline[2], scrp[2];
                    int64_t t1, t2;

                    w2d = -w2d;
                    if ((w1d==0 && w2d==0) || (w1d<0 || w2d<0))
                        continue;
                    ptonline[0] = (int32_t)(w2[0]+(w2d/(w1d+w2d))*w21[0]);
                    ptonline[1] = (int32_t)(w2[1]+(w2d/(w1d+w2d))*w21[1]);
                    scrp[0] = ptonline[0]-vect.x;
                    scrp[1] = ptonline[1]-vect.y;
                    if (scrv[0]*scrp[0] + scrv[1]*scrp[1] <= 0)
                        continue;
                    t1=scrp[0]; t2=scrp[1];
                    wdistsq = t1*t1 + t2*t2;
                    if (wdistsq < bestwdistsq)
                    {
                        bestk = k;
                        bestwdistsq = wdistsq;
                    }
                }

                if (bestk >= 0)
                    searchwall = sector[searchsector].wallptr + bestk;
            }
        }
        searchit = 0;
    }

    numscans = numbunches = 0;

    // MASKWALL_BAD_ACCESS
    // Fixes access of stale maskwall[maskwallcnt] (a "scan" index, in BUILD lingo):
    maskwallcnt = 0;

    if (globalcursectnum >= MAXSECTORS)
        globalcursectnum -= MAXSECTORS;
    else
    {
        i = globalcursectnum;
        updatesector(globalposx,globalposy,&globalcursectnum);
        if (globalcursectnum < 0) globalcursectnum = i;
    }

    polymost_scansector(globalcursectnum);

    if (inpreparemirror)
    {
        grhalfxdown10x = -grhalfxdown10;
        inpreparemirror = 0;

        // see engine.c: INPREPAREMIRROR_NO_BUNCHES
        if (numbunches > 0)
        {
            polymost_drawalls(0);
            numbunches--;
            bunchfirst[0] = bunchfirst[numbunches];
            bunchlast[0] = bunchlast[numbunches];
        }
    }
    else
        grhalfxdown10x = grhalfxdown10;

    while (numbunches > 0)
    {
        memset(ptempbuf,0,numbunches+3); ptempbuf[0] = 1;

        closest = 0;              //Almost works, but not quite :(
        for (i=1; i<numbunches; i++)
        {
            j = polymost_bunchfront(i,closest); if (j < 0) continue;
            ptempbuf[i] = 1;
            if (!j) { ptempbuf[closest] = 1; closest = i; }
        }
        for (i=0; i<numbunches; i++) //Double-check
        {
            if (ptempbuf[i]) continue;
            j = polymost_bunchfront(i,closest); if (j < 0) continue;
            ptempbuf[i] = 1;
            if (!j) { ptempbuf[closest] = 1; closest = i; i = 0; }
        }

        polymost_drawalls(closest);

        numbunches--;
        bunchfirst[closest] = bunchfirst[numbunches];
        bunchlast[closest] = bunchlast[numbunches];
    }
#ifdef USE_OPENGL
    if (getrendermode() >= REND_POLYMOST)
    {
        bglDepthFunc(GL_LEQUAL); //NEVER,LESS,(,L)EQUAL,GREATER,(NOT,G)EQUAL,ALWAYS

        //bglPolygonOffset(0,0);
        bglDepthRange(0.0,0.99999); //<- this is more widely supported than glPolygonOffset
    }
#endif

    enddrawing();
}

void polymost_drawmaskwall(int32_t damaskwallcnt)
{
    double dpx[8], dpy[8], dpx2[8], dpy2[8];
    float x0, x1, sx0, sy0, sx1, sy1, xp0, yp0, xp1, yp1, oxp0, oyp0, ryp0, ryp1;
    float r, t, t0, t1, csy[4], fsy[4];
    int32_t i, j, n, n2, z, sectnum, z1, z2, cz[4], fz[4], method;
    int32_t m0, m1;
    sectortype *sec, *nsec;
    walltype *wal, *wal2;

    z = maskwall[damaskwallcnt];
    wal = &wall[thewall[z]]; wal2 = &wall[wal->point2];
    sectnum = thesector[z]; sec = &sector[sectnum];

//    if (wal->nextsector < 0) return;
    // Without MASKWALL_BAD_ACCESS fix:
    // wal->nextsector is -1, WGR2 SVN Lochwood Hollow (Til' Death L1)  (or trueror1.map)

    nsec = &sector[wal->nextsector];
    z1 = max(nsec->ceilingz,sec->ceilingz);
    z2 = min(nsec->floorz,sec->floorz);

    globalpicnum = wal->overpicnum; if ((uint32_t)globalpicnum >= MAXTILES) globalpicnum = 0;
    globvis = globalvisibility;
    if (sector[sectnum].visibility != 0) globvis = mulscale4(globvis, (uint8_t)(sector[sectnum].visibility+16));

    DO_TILE_ANIM(globalpicnum, (int16_t)thewall[z]+16384);
    globalshade = (int32_t)wal->shade;
    globalpal = (int32_t)((uint8_t)wal->pal);
    globalorientation = (int32_t)wal->cstat;

    sx0 = (float)(wal->x-globalposx); sx1 = (float)(wal2->x-globalposx);
    sy0 = (float)(wal->y-globalposy); sy1 = (float)(wal2->y-globalposy);
    yp0 = sx0*gcosang2 + sy0*gsinang2;
    yp1 = sx1*gcosang2 + sy1*gsinang2;
    if ((yp0 < SCISDIST) && (yp1 < SCISDIST)) return;
    xp0 = sy0*gcosang - sx0*gsinang;
    xp1 = sy1*gcosang - sx1*gsinang;

    //Clip to close parallel-screen plane
    oxp0 = xp0; oyp0 = yp0;
    if (yp0 < SCISDIST) { t0 = (SCISDIST-yp0)/(yp1-yp0); xp0 = (xp1-xp0)*t0+xp0; yp0 = SCISDIST; }
    else t0 = 0.f;
    if (yp1 < SCISDIST) { t1 = (SCISDIST-oyp0)/(yp1-oyp0); xp1 = (xp1-oxp0)*t1+oxp0; yp1 = SCISDIST; }
    else { t1 = 1.f; }

    m0 = (int32_t)((wal2->x-wal->x)*t0+wal->x);
    m1 = (int32_t)((wal2->y-wal->y)*t0+wal->y);
    getzsofslope(sectnum,m0,m1,&cz[0],&fz[0]);
    getzsofslope(wal->nextsector,m0,m1,&cz[1],&fz[1]);
    m0 = (int32_t)((wal2->x-wal->x)*t1+wal->x);
    m1 = (int32_t)((wal2->y-wal->y)*t1+wal->y);
    getzsofslope(sectnum,m0,m1,&cz[2],&fz[2]);
    getzsofslope(wal->nextsector,m0,m1,&cz[3],&fz[3]);

    ryp0 = 1.f/yp0; ryp1 = 1.f/yp1;

    //Generate screen coordinates for front side of wall
    x0 = ghalfx*xp0*ryp0 + ghalfx;
    x1 = ghalfx*xp1*ryp1 + ghalfx;
    if (x1 <= x0) return;

    ryp0 *= gyxscale; ryp1 *= gyxscale;

    gdx = (ryp0-ryp1)*gxyaspect / (x0-x1);
    gdy = 0;
    gdo = ryp0*gxyaspect - gdx*x0;

    //gux*x0 + guo = t0*wal->xrepeat*8*yp0
    //gux*x1 + guo = t1*wal->xrepeat*8*yp1
    gux = (t0*ryp0 - t1*ryp1)*gxyaspect*(float)wal->xrepeat*8.f / (x0-x1);
    guo = t0*ryp0*gxyaspect*(float)wal->xrepeat*8.f - gux*x0;
    guo += (float)wal->xpanning*gdo;
    gux += (float)wal->xpanning*gdx;
    guy = 0;

    if (!(wal->cstat&4)) i = z1; else i = z2;

    // mask
    calc_ypanning(i, ryp0, ryp1, x0, x1, wal->ypanning, wal->yrepeat, 0);

    if (wal->cstat&8) //xflip
    {
        t = (float)(wal->xrepeat*8 + wal->xpanning*2);
        gux = gdx*t - gux;
        guy = gdy*t - guy;
        guo = gdo*t - guo;
    }
    if (wal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip

    method = 1; pow2xsplit = 1;
    if (wal->cstat&128) { if (!(wal->cstat&512)) method = 2; else method = 3; }

    calc_and_apply_fog(wal->picnum, wal->shade, sec->visibility, sec->floorpal);

    for (i=0; i<2; i++)
    {
        csy[i] = ((float)(cz[i]-globalposz))*ryp0 + ghoriz;
        fsy[i] = ((float)(fz[i]-globalposz))*ryp0 + ghoriz;
        csy[i+2] = ((float)(cz[i+2]-globalposz))*ryp1 + ghoriz;
        fsy[i+2] = ((float)(fz[i+2]-globalposz))*ryp1 + ghoriz;
    }

    //Clip 2 quadrilaterals
    //               /csy3
    //             /   |
    // csy0------/----csy2
    //   |     /xxxxxxx|
    //   |   /xxxxxxxxx|
    // csy1/xxxxxxxxxxx|
    //   |xxxxxxxxxxx/fsy3
    //   |xxxxxxxxx/   |
    //   |xxxxxxx/     |
    // fsy0----/------fsy2
    //   |   /
    // fsy1/

    dpx[0] = x0; dpy[0] = csy[1];
    dpx[1] = x1; dpy[1] = csy[3];
    dpx[2] = x1; dpy[2] = fsy[3];
    dpx[3] = x0; dpy[3] = fsy[1];
    n = 4;

    //Clip to (x0,csy[0])-(x1,csy[2])
    n2 = 0; t1 = -((dpx[0]-x0)*(csy[2]-csy[0]) - (dpy[0]-csy[0])*(x1-x0));
    for (i=0; i<n; i++)
    {
        j = i+1; if (j >= n) j = 0;

        t0 = t1; t1 = -((dpx[j]-x0)*(csy[2]-csy[0]) - (dpy[j]-csy[0])*(x1-x0));
        if (t0 >= 0) { dpx2[n2] = dpx[i]; dpy2[n2] = dpy[i]; n2++; }
        if ((t0 >= 0) != (t1 >= 0))
        {
            r = t0/(t0-t1);
            dpx2[n2] = (dpx[j]-dpx[i])*r + dpx[i];
            dpy2[n2] = (dpy[j]-dpy[i])*r + dpy[i];
            n2++;
        }
    }
    if (n2 < 3) return;

    //Clip to (x1,fsy[2])-(x0,fsy[0])
    n = 0; t1 = -((dpx2[0]-x1)*(fsy[0]-fsy[2]) - (dpy2[0]-fsy[2])*(x0-x1));
    for (i=0; i<n2; i++)
    {
        j = i+1; if (j >= n2) j = 0;

        t0 = t1; t1 = -((dpx2[j]-x1)*(fsy[0]-fsy[2]) - (dpy2[j]-fsy[2])*(x0-x1));
        if (t0 >= 0) { dpx[n] = dpx2[i]; dpy[n] = dpy2[i]; n++; }
        if ((t0 >= 0) != (t1 >= 0))
        {
            r = t0/(t0-t1);
            dpx[n] = (dpx2[j]-dpx2[i])*r + dpx2[i];
            dpy[n] = (dpy2[j]-dpy2[i])*r + dpy2[i];
            n++;
        }
    }
    if (n < 3) return;

    pow2xsplit = 0;
    skyclamphack = 0;
    alpha = 0.f;
    drawpoly(dpx,dpy,n,method);
}

void polymost_drawsprite(int32_t snum)
{
    double px[6], py[6];
    float f, c, s, fx, fy, sx0, sy0, sx1, xp0, yp0, xp1, yp1, oxp0, oyp0, ryp0, ryp1, ft[4];
    float x0, y0, x1, y1, sc0, sf0, sc1, sf1, px2[6], py2[6], xv, yv, t0, t1;
    int32_t i, j, spritenum, xoff=0, yoff=0, method, npoints;
    int32_t posx,posy;
    int32_t oldsizx, oldsizy;
    int32_t tsizx, tsizy;

    spritetype *const tspr = tspriteptr[snum];
    if (bad_tspr(tspr))
        return;

    spritenum         = tspr->owner;

    DO_TILE_ANIM(tspr->picnum, spritenum+32768);

    globalpicnum      = tspr->picnum;
    globalshade       = tspr->shade;
    globalpal         = tspr->pal;
    globalorientation = tspr->cstat;
    globvis = globalvisibility;
    if (sector[tspr->sectnum].visibility != 0) globvis = mulscale4(globvis, (uint8_t)(sector[tspr->sectnum].visibility+16));
    if ((globalorientation&48) != 48)  	// only non-voxel sprites should do this
    {
        int32_t flag;
        flag = usehightile && h_xsize[globalpicnum];
        xoff = (int32_t)tspr->xoffset;
        yoff = (int32_t)tspr->yoffset;
        xoff += flag ? h_xoffs[globalpicnum] : picanm[globalpicnum].xofs;
        yoff += flag ? h_yoffs[globalpicnum] : picanm[globalpicnum].yofs;
    }

    method = 1+4;
    if (tspr->cstat&2) { if (!(tspr->cstat&512)) method = 2+4; else method = 3+4; }

    alpha = spriteext[spritenum].alpha;

#ifdef USE_OPENGL
    calc_and_apply_fog(tspr->picnum, globalshade, sector[tspr->sectnum].visibility, sector[tspr->sectnum].floorpal);

    while (getrendermode() >= REND_POLYMOST && !(spriteext[spritenum].flags&SPREXT_NOTMD))
    {
        if (usemodels && tile2model[Ptile2tile(tspr->picnum,tspr->pal)].modelid >= 0 && tile2model[Ptile2tile(tspr->picnum,tspr->pal)].framenum >= 0)
        {
            if (spritenum >= MAXSPRITES || tspr->statnum == TSPR_MIRROR)
            {
                if (mddraw(tspr)) return;
                break;	// else, render as flat sprite
            }

            if (mddraw(tspr))
                return;

            break;	// else, render as flat sprite
        }

        if (usevoxels && (tspr->cstat&48)!=48 && tiletovox[tspr->picnum] >= 0 && voxmodels[tiletovox[tspr->picnum]])
        {
            if (voxdraw(voxmodels[tiletovox[tspr->picnum]], tspr))
                return;
            break;	// else, render as flat sprite
        }

        if ((tspr->cstat&48)==48 && voxmodels[tspr->picnum])
        {
            voxdraw(voxmodels[tspr->picnum], tspr);
            return;
        }
        break;
    }

    if (((tspr->cstat&2) || (gltexmayhavealpha(tspr->picnum,tspr->pal))))
    {
        curpolygonoffset += 0.01f;
        bglEnable(GL_POLYGON_OFFSET_FILL);
        bglPolygonOffset(-curpolygonoffset, -curpolygonoffset);
    }
#endif

    posx=tspr->x;
    posy=tspr->y;
    if (spriteext[spritenum].flags&SPREXT_AWAY1)
    {
        posx+=(sintable[(tspr->ang+512)&2047]>>13);
        posy+=(sintable[(tspr->ang)&2047]>>13);
    }
    else if (spriteext[spritenum].flags&SPREXT_AWAY2)
    {
        posx-=(sintable[(tspr->ang+512)&2047]>>13);
        posy-=(sintable[(tspr->ang)&2047]>>13);
    }

    oldsizx=tsizx=tilesizx[globalpicnum];
    oldsizy=tsizy=tilesizy[globalpicnum];
    if (usehightile && h_xsize[globalpicnum])
    {
        tsizx = h_xsize[globalpicnum];
        tsizy = h_ysize[globalpicnum];
    }

    if (tsizx<=0 || tsizy<=0)
        return;

    switch ((globalorientation>>4)&3)
    {
    case 0: //Face sprite
        //Project 3D to 2D
        if (globalorientation&4) xoff = -xoff;
        // NOTE: yoff not negated not for y flipping, unlike wall and floor
        // aligned sprites.

        sx0 = (float)(tspr->x-globalposx);
        sy0 = (float)(tspr->y-globalposy);
        xp0 = sy0*gcosang  - sx0*gsinang;
        yp0 = sx0*gcosang2 + sy0*gsinang2;
        if (yp0 <= SCISDIST) return;
        ryp0 = 1/yp0;
        sx0 = ghalfx*xp0*ryp0 + ghalfx;
        sy0 = ((float)(tspr->z-globalposz))*gyxscale*ryp0 + ghoriz;

        f = ryp0*(float)xdimen/160.0;
        fx = ((float)tspr->xrepeat)*f;
        fy = ((float)tspr->yrepeat)*f*((float)yxaspect/65536.0);
        sx0 -= fx*(float)xoff; if (tsizx&1) sx0 += fx*.5;
        sy0 -= fy*(float)yoff;
        fx *= ((float)tsizx);
        fy *= ((float)tsizy);

        px[0] = px[3] = sx0-fx*.5; px[1] = px[2] = sx0+fx*.5;
        if (!(globalorientation&128)) { py[0] = py[1] = sy0-fy; py[2] = py[3] = sy0; }
        else { py[0] = py[1] = sy0-fy*.5; py[2] = py[3] = sy0+fy*.5; }

        gdx = gdy = guy = gvx = 0; gdo = ryp0*gviewxrange;
        if (!(globalorientation&4))
            { gux = (float)tsizx*gdo/(px[1]-px[0]+.002); guo = -gux*(px[0]-.001); }
        else { gux = (float)tsizx*gdo/(px[0]-px[1]-.002); guo = -gux*(px[1]+.001); }
        if (!(globalorientation&8))
            { gvy = (float)tsizy*gdo/(py[3]-py[0]+.002); gvo = -gvy*(py[0]-.001); }
        else { gvy = (float)tsizy*gdo/(py[0]-py[3]-.002); gvo = -gvy*(py[3]+.001); }

        // sprite panning
        guy -= gdy*((float)(spriteext[spritenum].xpanning)/255.f)*tsizx;
        guo -= gdo*((float)(spriteext[spritenum].xpanning)/255.f)*tsizx;
        gvy -= gdy*((float)(spriteext[spritenum].ypanning)/255.f)*tsizy;
        gvo -= gdo*((float)(spriteext[spritenum].ypanning)/255.f)*tsizy;

        //Clip sprites to ceilings/floors when no parallaxing and not sloped
        if (!(sector[tspr->sectnum].ceilingstat&3))
        {
            sy0 = ((float)(sector[tspr->sectnum].ceilingz-globalposz))*gyxscale*ryp0 + ghoriz;
            if (py[0] < sy0) py[0] = py[1] = sy0;
        }
        if (!(sector[tspr->sectnum].floorstat&3))
        {
            sy0 = ((float)(sector[tspr->sectnum].floorz-globalposz))*gyxscale*ryp0 + ghoriz;
            if (py[2] > sy0) py[2] = py[3] = sy0;
        }

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 1;
        if (spriteext[spritenum].ypanning)
            trepeat = 1;
#endif
        tilesizx[globalpicnum] = tsizx;
        tilesizy[globalpicnum] = tsizy;
        pow2xsplit = 0; drawpoly(px,py,4,method);

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 0;
        if (spriteext[spritenum].ypanning)
            trepeat = 0;
#endif

        break;
    case 1: //Wall sprite

        //Project 3D to 2D
        if (globalorientation&4) xoff = -xoff;
        if (globalorientation&8) yoff = -yoff;

        xv = (float)tspr->xrepeat * (float)sintable[(tspr->ang)&2047] / 65536.0;
        yv = (float)tspr->xrepeat * (float)sintable[(tspr->ang+1536)&2047] / 65536.0;
        f = (float)(tsizx>>1) + (float)xoff;
        x0 = (float)(posx-globalposx) - xv*f; x1 = xv*(float)tsizx + x0;
        y0 = (float)(posy-globalposy) - yv*f; y1 = yv*(float)tsizx + y0;

        yp0 = x0*gcosang2 + y0*gsinang2;
        yp1 = x1*gcosang2 + y1*gsinang2;
        if ((yp0 <= SCISDIST) && (yp1 <= SCISDIST)) return;
        xp0 = y0*gcosang - x0*gsinang;
        xp1 = y1*gcosang - x1*gsinang;

        //Clip to close parallel-screen plane
        oxp0 = xp0; oyp0 = yp0;
        if (yp0 < SCISDIST) { t0 = (SCISDIST-yp0)/(yp1-yp0); xp0 = (xp1-xp0)*t0+xp0; yp0 = SCISDIST; }
        else { t0 = 0.f; }
        if (yp1 < SCISDIST) { t1 = (SCISDIST-oyp0)/(yp1-oyp0); xp1 = (xp1-oxp0)*t1+oxp0; yp1 = SCISDIST; }
        else { t1 = 1.f; }

        f = ((float)tspr->yrepeat) * (float)tsizy * 4;

        ryp0 = 1.0/yp0;
        ryp1 = 1.0/yp1;
        sx0 = ghalfx*xp0*ryp0 + ghalfx;
        sx1 = ghalfx*xp1*ryp1 + ghalfx;
        ryp0 *= gyxscale;
        ryp1 *= gyxscale;

        tspr->z -= ((yoff*tspr->yrepeat)<<2);
        if (globalorientation&128)
        {
            tspr->z += ((tsizy*tspr->yrepeat)<<1);
            if (tsizy&1) tspr->z += (tspr->yrepeat<<1); //Odd yspans
        }

        sc0 = ((float)(tspr->z-globalposz-f))*ryp0 + ghoriz;
        sc1 = ((float)(tspr->z-globalposz-f))*ryp1 + ghoriz;
        sf0 = ((float)(tspr->z-globalposz))*ryp0 + ghoriz;
        sf1 = ((float)(tspr->z-globalposz))*ryp1 + ghoriz;

        gdx = (ryp0-ryp1)*gxyaspect / (sx0-sx1);
        gdy = 0;
        gdo = ryp0*gxyaspect - gdx*sx0;

        //Original equations:
        //(gux*sx0 + guo)/(gdx*sx1 + gdo) = tsizx*t0
        //(gux*sx1 + guo)/(gdx*sx1 + gdo) = tsizx*t1
        //
        // gvx*sx0 + gvy*sc0 + gvo = 0
        // gvy*sx1 + gvy*sc1 + gvo = 0
        //(gvx*sx0 + gvy*sf0 + gvo)/(gdx*sx0 + gdo) = tsizy
        //(gvx*sx1 + gvy*sf1 + gvo)/(gdx*sx1 + gdo) = tsizy

        //gux*sx0 + guo = t0*tsizx*yp0
        //gux*sx1 + guo = t1*tsizx*yp1
        if (globalorientation&4) { t0 = 1.f-t0; t1 = 1.f-t1; }

        //sprite panning
        t0 -= ((float)(spriteext[spritenum].xpanning)/255.f);
        t1 -= ((float)(spriteext[spritenum].xpanning)/255.f);
        gux = (t0*ryp0 - t1*ryp1)*gxyaspect*(float)tsizx / (sx0-sx1);
        guy = 0;
        guo = t0*ryp0*gxyaspect*(float)tsizx - gux*sx0;

        //gvx*sx0 + gvy*sc0 + gvo = 0
        //gvx*sx1 + gvy*sc1 + gvo = 0
        //gvx*sx0 + gvy*sf0 + gvo = tsizy*(gdx*sx0 + gdo)
        f = ((float)tsizy)*(gdx*sx0 + gdo) / ((sx0-sx1)*(sc0-sf0));
        if (!(globalorientation&8))
        {
            gvx = (sc0-sc1)*f;
            gvy = (sx1-sx0)*f;
            gvo = -gvx*sx0 - gvy*sc0;
        }
        else
        {
            gvx = (sf1-sf0)*f;
            gvy = (sx0-sx1)*f;
            gvo = -gvx*sx0 - gvy*sf0;
        }

        // sprite panning
        gvx -= gdx*((float)(spriteext[spritenum].ypanning)/255.f)*tsizy;
        gvy -= gdy*((float)(spriteext[spritenum].ypanning)/255.f)*tsizy;
        gvo -= gdo*((float)(spriteext[spritenum].ypanning)/255.f)*tsizy;

        //Clip sprites to ceilings/floors when no parallaxing
        if (!(sector[tspr->sectnum].ceilingstat&1))
        {
            f = ((float)tspr->yrepeat) * (float)tsizy * 4;
            if (sector[tspr->sectnum].ceilingz > tspr->z-f)
            {
                sc0 = ((float)(sector[tspr->sectnum].ceilingz-globalposz))*ryp0 + ghoriz;
                sc1 = ((float)(sector[tspr->sectnum].ceilingz-globalposz))*ryp1 + ghoriz;
            }
        }
        if (!(sector[tspr->sectnum].floorstat&1))
        {
            if (sector[tspr->sectnum].floorz < tspr->z)
            {
                sf0 = ((float)(sector[tspr->sectnum].floorz-globalposz))*ryp0 + ghoriz;
                sf1 = ((float)(sector[tspr->sectnum].floorz-globalposz))*ryp1 + ghoriz;
            }
        }

        if (sx0 > sx1)
        {
            if (globalorientation&64) return; //1-sided sprite
            f = sx0; sx0 = sx1; sx1 = f;
            f = sc0; sc0 = sc1; sc1 = f;
            f = sf0; sf0 = sf1; sf1 = f;
        }

        px[0] = sx0; py[0] = sc0;
        px[1] = sx1; py[1] = sc1;
        px[2] = sx1; py[2] = sf1;
        px[3] = sx0; py[3] = sf0;

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 1;
        if (spriteext[spritenum].ypanning)
            trepeat = 1;
#endif

        tilesizx[globalpicnum] = tsizx;
        tilesizy[globalpicnum] = tsizy;
        pow2xsplit = 0; drawpoly(px,py,4,method);

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 0;
        if (spriteext[spritenum].ypanning)
            trepeat = 0;
#endif

        break;
    case 2: //Floor sprite

        if ((globalorientation&64) != 0)
            if ((globalposz > tspr->z) == (!(globalorientation&8)))
                return;
        if ((globalorientation&4) > 0) xoff = -xoff;
        if ((globalorientation&8) > 0) yoff = -yoff;

        i = (tspr->ang&2047);
        c = sintable[(i+512)&2047]/65536.0;
        s = sintable[i]/65536.0;
        x0 = (float)((tsizx>>1)-xoff)*tspr->xrepeat;
        y0 = (float)((tsizy>>1)-yoff)*tspr->yrepeat;
        x1 = (float)((tsizx>>1)+xoff)*tspr->xrepeat;
        y1 = (float)((tsizy>>1)+yoff)*tspr->yrepeat;

        //Project 3D to 2D
        for (j=0; j<4; j++)
        {
            sx0 = (float)(tspr->x-globalposx);
            sy0 = (float)(tspr->y-globalposy);
            if ((j+0)&2) { sy0 -= s*y0; sx0 -= c*y0; }
            else { sy0 += s*y1; sx0 += c*y1; }
            if ((j+1)&2) { sx0 -= s*x0; sy0 += c*x0; }
            else { sx0 += s*x1; sy0 -= c*x1; }
            px[j] = sy0*gcosang  - sx0*gsinang;
            py[j] = sx0*gcosang2 + sy0*gsinang2;
        }

        if (tspr->z < globalposz) //if floor sprite is above you, reverse order of points
        {
            f = px[0]; px[0] = px[1]; px[1] = f;
            f = py[0]; py[0] = py[1]; py[1] = f;
            f = px[2]; px[2] = px[3]; px[3] = f;
            f = py[2]; py[2] = py[3]; py[3] = f;
        }

        //Clip to SCISDIST plane
        npoints = 0;
        for (i=0; i<4; i++)
        {
            j = ((i+1)&3);
            if (py[i] >= SCISDIST) { px2[npoints] = px[i]; py2[npoints] = py[i]; npoints++; }
            if ((py[i] >= SCISDIST) != (py[j] >= SCISDIST))
            {
                f = (SCISDIST-py[i])/(py[j]-py[i]);
                px2[npoints] = (px[j]-px[i])*f + px[i];
                py2[npoints] = (py[j]-py[i])*f + py[i]; npoints++;
            }
        }
        if (npoints < 3) return;

        //Project rotated 3D points to screen
        f = ((float)(tspr->z-globalposz))*gyxscale;
        for (j=0; j<npoints; j++)
        {
            ryp0 = 1/py2[j];
            px[j] = ghalfx*px2[j]*ryp0 + ghalfx;
            py[j] = f*ryp0 + ghoriz;
        }

        //gd? Copied from floor rendering code
        gdx = 0;
        gdy = gxyaspect / (double)(tspr->z-globalposz);
        gdo = -ghoriz*gdy;
        //copied&modified from relative alignment
        xv = (float)tspr->x + s*x1 + c*y1; fx = (double)-(x0+x1)*s;
        yv = (float)tspr->y + s*y1 - c*x1; fy = (double)+(x0+x1)*c;
        f = 1.0/sqrt(fx*fx+fy*fy); fx *= f; fy *= f;
        ft[2] = singlobalang*fy + cosglobalang*fx;
        ft[3] = singlobalang*fx - cosglobalang*fy;
        ft[0] = ((double)(globalposy-yv))*fy + ((double)(globalposx-xv))*fx;
        ft[1] = ((double)(globalposx-xv))*fy - ((double)(globalposy-yv))*fx;
        gux = (double)ft[3]*((double)viewingrange)/(-65536.0*262144.0);
        gvx = (double)ft[2]*((double)viewingrange)/(-65536.0*262144.0);
        guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
        guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
        guo += (double)(ft[2]/262144.0-gux)*ghalfx;
        gvo -= (double)(ft[3]/262144.0+gvx)*ghalfx;
        f = 4.0/(float)tspr->xrepeat; gux *= f; guy *= f; guo *= f;
        f =-4.0/(float)tspr->yrepeat; gvx *= f; gvy *= f; gvo *= f;
        if (globalorientation&4)
        {
            gux = ((float)tsizx)*gdx - gux;
            guy = ((float)tsizx)*gdy - guy;
            guo = ((float)tsizx)*gdo - guo;
        }

        // sprite panning
        guy -= gdy*((float)(spriteext[spritenum].xpanning)/255.f)*tsizx;
        guo -= gdo*((float)(spriteext[spritenum].xpanning)/255.f)*tsizx;
        gvy -= gdy*((float)(spriteext[spritenum].ypanning)/255.f)*tsizy;
        gvo -= gdo*((float)(spriteext[spritenum].ypanning)/255.f)*tsizy;

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 1;
        if (spriteext[spritenum].ypanning)
            trepeat = 1;
#endif

        tilesizx[globalpicnum] = tsizx;
        tilesizy[globalpicnum] = tsizy;
        pow2xsplit = 0; drawpoly(px,py,npoints,method);

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 0;
        if (spriteext[spritenum].ypanning)
            trepeat = 0;
#endif

        break;

    case 3: //Voxel sprite
        break;
    }
    tilesizx[globalpicnum]=oldsizx;
    tilesizy[globalpicnum]=oldsizy;
}

//sx,sy       center of sprite; screen coords*65536
//z           zoom*65536. > is zoomed in
//a           angle (0 is default)
//dastat&1    1:translucence
//dastat&2    1:auto-scale mode (use 320*200 coordinates)
//dastat&4    1:y-flip
//dastat&8    1:don't clip to startumost/startdmost
//dastat&16   1:force point passed to be top-left corner, 0:Editart center
//dastat&32   1:reverse translucence
//dastat&64   1:non-masked, 0:masked
//dastat&128  1:draw all pages (permanent)
//cx1,...     clip window (actual screen coords)
void polymost_dorotatesprite(int32_t sx, int32_t sy, int32_t z, int16_t a, int16_t picnum,
                             int8_t dashade, char dapalnum, int32_t dastat, uint8_t daalpha,
                             int32_t cx1, int32_t cy1, int32_t cx2, int32_t cy2, int32_t uniqid)
{
    static int32_t onumframes = 0;

    int32_t n, nn, xoff, yoff, xsiz, ysiz, method;
    int32_t ogpicnum, ogshade, ogpal, ofoffset;
    double ogchang, ogshang, ogctang, ogstang, oghalfx, oghoriz;
    double ogrhalfxdown10, ogrhalfxdown10x;
    double d, cosang, sinang, cosang2, sinang2, px[8], py[8], px2[8], py2[8];
    float m[4][4];

    int32_t ourxyaspect;

#if defined(USE_OPENGL) && defined(POLYMER)
    int32_t olddetailmapping = r_detailmapping, oldglowmapping = r_glowmapping;
#endif

#ifdef USE_OPENGL
    if (getrendermode() >= REND_POLYMOST && usemodels && hudmem[(dastat&4)>>2][picnum].angadd)
    {
        const int32_t tilenum = Ptile2tile(picnum,dapalnum);

        if (tile2model[tilenum].modelid >= 0 &&
            tile2model[tilenum].framenum >= 0)
        {
            int32_t oldviewingrange;
            double ogxyaspect;
            double x1, y1, z1;

            spritetype tspr;
            memset(&tspr,0,sizeof(spritetype));

            if (hudmem[(dastat&4)>>2][picnum].flags&1) return; //"HIDE" is specified in DEF

            ogchang = gchang; gchang = 1.0;
            ogshang = gshang; gshang = 0.0; d = (double)z/(65536.0*16384.0);
            ogctang = gctang; gctang = (double)sintable[(a+512)&2047]*d;
            ogstang = gstang; gstang = (double)sintable[a&2047]*d;
            ogshade  = globalshade;  globalshade  = dashade;
            ogpal    = globalpal;    globalpal    = (int32_t)((uint8_t)dapalnum);
            ogxyaspect = gxyaspect; gxyaspect = 1.0;
            oldviewingrange = viewingrange; viewingrange = 65536;

            x1 = hudmem[(dastat&4)>>2][picnum].xadd;
            y1 = hudmem[(dastat&4)>>2][picnum].yadd;
            z1 = hudmem[(dastat&4)>>2][picnum].zadd;
            
#ifdef POLYMER
            if (pr_overridehud) {
                x1 = pr_hudxadd;
                y1 = pr_hudyadd;
                z1 = pr_hudzadd;
            }
#endif

            if (!(hudmem[(dastat&4)>>2][picnum].flags&2)) //"NOBOB" is specified in DEF
            {
                double fx = ((double)sx)*(1.0/65536.0);
                double fy = ((double)sy)*(1.0/65536.0);

                if (dastat&16)
                {
                    xsiz = tilesizx[picnum]; ysiz = tilesizy[picnum];
                    xoff = picanm[picnum].xofs + (xsiz>>1);
                    yoff = picanm[picnum].yofs + (ysiz>>1);

                    d = (double)z/(65536.0*16384.0);
                    cosang2 = cosang = (double)sintable[(a+512)&2047]*d;
                    sinang2 = sinang = (double)sintable[a&2047]*d;
                    if ((dastat&2) || (!(dastat&8))) //Don't aspect unscaled perms
                        { d = (double)xyaspect/65536.0; cosang2 *= d; sinang2 *= d; }
                    fx += -(double)xoff*cosang2+ (double)yoff*sinang2;
                    fy += -(double)xoff*sinang - (double)yoff*cosang;
                }

                if (!(dastat&2))
                {
                    x1 += fx/((double)(xdim<<15))-1.0; //-1: left of screen, +1: right of screen
                    y1 += fy/((double)(ydim<<15))-1.0; //-1: top of screen, +1: bottom of screen
                }
                else
                {
                    x1 += fx/160.0-1.0; //-1: left of screen, +1: right of screen
                    y1 += fy/100.0-1.0; //-1: top of screen, +1: bottom of screen
                }
            }
            tspr.ang = hudmem[(dastat&4)>>2][picnum].angadd+globalang;

#ifdef POLYMER
            if (pr_overridehud) {
                tspr.ang = pr_hudangadd + globalang;
            }
#endif

            if (dastat&4) { x1 = -x1; y1 = -y1; }

            // In Polymost, we don't care if the model is very big
            if (getrendermode() < REND_POLYMER)
            {
                tspr.xrepeat = tspr.yrepeat = 32;

                tspr.x = (int32_t)(((double)gcosang*z1 - (double)gsinang*x1)*16384.0 + globalposx);
                tspr.y = (int32_t)(((double)gsinang*z1 + (double)gcosang*x1)*16384.0 + globalposy);
                tspr.z = (int32_t)(globalposz + y1*16384.0*0.8);
            }
            else
            {
                float x, y, z;

                tspr.xrepeat = tspr.yrepeat = 5;

                x = (float)(((double)gcosang*z1 - (double)gsinang*x1)*2560.0 + globalposx);
                y = (float)(((double)gsinang*z1 + (double)gcosang*x1)*2560.0 + globalposy);
                z = (float)(globalposz + y1*2560.0*0.8);

                memcpy(&tspr.x, &x, sizeof(float));
                memcpy(&tspr.y, &y, sizeof(float));
                memcpy(&tspr.z, &z, sizeof(float));
            }
            tspr.picnum = picnum;
            tspr.shade = dashade;
            tspr.pal = dapalnum;
            tspr.owner = uniqid+MAXSPRITES;
            globalorientation = (dastat&1)+((dastat&32)<<4)+((dastat&4)<<1);
            tspr.cstat = globalorientation;

            if ((dastat&10) == 2)
                bglViewport(windowx1,yres-(windowy2+1),windowx2-windowx1+1,windowy2-windowy1+1);
            else
            {
                bglViewport(0,0,xdim,ydim);
                glox1 = -1; //Force fullscreen (glox1=-1 forces it to restore)
            }

            if (getrendermode() < REND_POLYMER)
            {
                bglMatrixMode(GL_PROJECTION);
                memset(m,0,sizeof(m));
                if ((dastat&10) == 2)
                {
                    float ratioratio = (float)xdim/ydim;
                    m[0][0] = (float)ydimen*(ratioratio >= 1.6?1.2:1); m[0][2] = 1.0;
                    m[1][1] = (float)xdimen; m[1][2] = 1.0;
                    m[2][2] = 1.0; m[2][3] = (float)ydimen*(ratioratio >= 1.6?1.2:1);
                    m[3][2] =-1.0;
                }
                else { m[0][0] = m[2][3] = 1.0f; m[1][1] = ((float)xdim)/((float)ydim); m[2][2] = 1.0001f; m[3][2] = 1-m[2][2]; }
                bglLoadMatrixf(&m[0][0]);
                bglMatrixMode(GL_MODELVIEW);
                bglLoadIdentity();
            }

            if (hudmem[(dastat&4)>>2][picnum].flags&8) //NODEPTH flag
                bglDisable(GL_DEPTH_TEST);
            else
            {
                bglEnable(GL_DEPTH_TEST);
                if (onumframes != numframes)
                {
                    onumframes = numframes;
                    bglClear(GL_DEPTH_BUFFER_BIT);
                }
            }

#ifdef USE_OPENGL
            spriteext[tspr.owner].alpha = daalpha / 255.0f;

            if (!nofog) bglDisable(GL_FOG);
            if (getrendermode() < REND_POLYMER)
                mddraw(&tspr);
# ifdef POLYMER
            else
            {
                int32_t fov;

                tspriteptr[MAXSPRITESONSCREEN] = &tspr;

                bglEnable(GL_ALPHA_TEST);
                bglEnable(GL_BLEND);

                spriteext[tspr.owner].roll = a;
                spriteext[tspr.owner].zoff = z;
                
                fov = hudmem[(dastat&4)>>2][picnum].fov;
                
                if (fov == -1) {
                    fov = pr_fov;
                }
                
                if (pr_overridehud) {
                    fov = pr_hudfov;
                }
                
                polymer_setaspect(fov);

                polymer_drawsprite(MAXSPRITESONSCREEN);
                
                polymer_setaspect(pr_fov);

                spriteext[tspr.owner].zoff = 0;
                spriteext[tspr.owner].roll = 0;

                bglDisable(GL_BLEND);
                bglDisable(GL_ALPHA_TEST);
            }
# endif
            if (!nofog) bglEnable(GL_FOG);
#else
            mddraw(&tspr);

            spriteext[tspr.owner].alpha = 0.f;
#endif
            viewingrange = oldviewingrange;
            gxyaspect = ogxyaspect;
            globalshade  = ogshade;
            globalpal    = ogpal;
            gchang = ogchang;
            gshang = ogshang;
            gctang = ogctang;
            gstang = ogstang;

            return;
        }
    }
#endif

    globvis = 0;
    ogpicnum = globalpicnum; globalpicnum = picnum;
    ogshade  = globalshade;  globalshade  = dashade;
    ogpal    = globalpal;    globalpal    = (int32_t)((uint8_t)dapalnum);
    oghalfx  = ghalfx;       ghalfx       = (double)(xdim>>1);
    ogrhalfxdown10 = grhalfxdown10;    grhalfxdown10 = 1.0/(((double)ghalfx)*1024);
    ogrhalfxdown10x = grhalfxdown10x;  grhalfxdown10x = grhalfxdown10;
    oghoriz  = ghoriz;       ghoriz       = (double)(ydim>>1);
    ofoffset = frameoffset;  frameoffset  = frameplace;
    ogchang = gchang; gchang = 1.0;
    ogshang = gshang; gshang = 0.0;
    ogctang = gctang; gctang = 1.0;
    ogstang = gstang; gstang = 0.0;

#ifdef USE_OPENGL
    if (getrendermode() >= REND_POLYMOST)
    {
        bglViewport(0,0,xdim,ydim); glox1 = -1; //Force fullscreen (glox1=-1 forces it to restore)
        bglMatrixMode(GL_PROJECTION);
        memset(m,0,sizeof(m));
        m[0][0] = m[2][3] = 1.0f; m[1][1] = ((float)xdim)/((float)ydim); m[2][2] = 1.0001f; m[3][2] = 1-m[2][2];
        bglPushMatrix(); bglLoadMatrixf(&m[0][0]);
        bglMatrixMode(GL_MODELVIEW);
        bglPushMatrix();
        bglLoadIdentity();

        bglDisable(GL_DEPTH_TEST);
        bglDisable(GL_ALPHA_TEST);
        bglEnable(GL_TEXTURE_2D);
        
# ifdef POLYMER
        if (getrendermode() == REND_POLYMER) {
            polymer_inb4rotatesprite(picnum, dapalnum, dashade);
            r_detailmapping = 0;
            r_glowmapping = 0;
        }
# endif
    }
#endif

    method = 0;
    if (!(dastat&64))
    {
        method = 1;
        if (dastat&1) { if (!(dastat&32)) method = 2; else method = 3; }
    }
    method |= 4; //Use OpenGL clamping - dorotatesprite never repeats

    alpha = daalpha / 255.0f;

    xsiz = tilesizx[globalpicnum];
    ysiz = tilesizy[globalpicnum];

    if (dastat&16)
    {
        xoff = 0;
        yoff = 0;
    }
    else
    {
        xoff = picanm[globalpicnum].xofs + (xsiz>>1);
        yoff = picanm[globalpicnum].yofs + (ysiz>>1);
    }

    if (dastat&4)
        yoff = ysiz-yoff;

    {
        int32_t temp;
        dorotspr_handle_bit2(&sx, &sy, &z, dastat, cx1+cx2, cy1+cy2, &temp, &ourxyaspect);
    }

    d = (double)z/(65536.0*16384.0);
    cosang2 = cosang = (double)sintable[(a+512)&2047]*d;
    sinang2 = sinang = (double)sintable[a&2047]*d;
    if ((dastat&2) || (!(dastat&8))) //Don't aspect unscaled perms
    {
        d = (double)ourxyaspect/65536.0;
        cosang2 *= d;
        sinang2 *= d;
    }

    px[0] = (double)sx/65536.0 - (double)xoff*cosang2+ (double)yoff*sinang2;
    py[0] = (double)sy/65536.0 - (double)xoff*sinang - (double)yoff*cosang;
    px[1] = px[0] + (double)xsiz*cosang2;
    py[1] = py[0] + (double)xsiz*sinang;
    px[3] = px[0] - (double)ysiz*sinang2;
    py[3] = py[0] + (double)ysiz*cosang;
    px[2] = px[1]+px[3]-px[0];
    py[2] = py[1]+py[3]-py[0];
    n = 4;

    gdx = 0; gdy = 0; gdo = 1.0;
    //px[0]*gux + py[0]*guy + guo = 0
    //px[1]*gux + py[1]*guy + guo = xsiz-.0001
    //px[3]*gux + py[3]*guy + guo = 0
    d = 1.0/(px[0]*(py[1]-py[3]) + px[1]*(py[3]-py[0]) + px[3]*(py[0]-py[1]));
    gux = (py[3]-py[0])*((double)xsiz-.0001)*d;
    guy = (px[0]-px[3])*((double)xsiz-.0001)*d;
    guo = 0 - px[0]*gux - py[0]*guy;

    if (!(dastat&4))
    {
        //px[0]*gvx + py[0]*gvy + gvo = 0
        //px[1]*gvx + py[1]*gvy + gvo = 0
        //px[3]*gvx + py[3]*gvy + gvo = ysiz-.0001
        gvx = (py[0]-py[1])*((double)ysiz-.0001)*d;
        gvy = (px[1]-px[0])*((double)ysiz-.0001)*d;
        gvo = 0 - px[0]*gvx - py[0]*gvy;
    }
    else
    {
        //px[0]*gvx + py[0]*gvy + gvo = ysiz-.0001
        //px[1]*gvx + py[1]*gvy + gvo = ysiz-.0001
        //px[3]*gvx + py[3]*gvy + gvo = 0
        gvx = (py[1]-py[0])*((double)ysiz-.0001)*d;
        gvy = (px[0]-px[1])*((double)ysiz-.0001)*d;
        gvo = (double)ysiz-.0001 - px[0]*gvx - py[0]*gvy;
    }

    cx2++; cy2++;
    //Clippoly4 (converted from int32_t to double)
    nn = z = 0;
    do
    {
        double fx, x1, x2;
        int32_t zz = z+1; if (zz == n) zz = 0;
        x1 = px[z]; x2 = px[zz]-x1; if ((cx1 <= x1) && (x1 <= cx2)) { px2[nn] = x1; py2[nn] = py[z]; nn++; }
        if (x2 <= 0) fx = cx2; else fx = cx1;  d = fx-x1;
        if ((d < x2) != (d < 0)) { px2[nn] = fx; py2[nn] = (py[zz]-py[z])*d/x2 + py[z]; nn++; }
        if (x2 <= 0) fx = cx1; else fx = cx2;  d = fx-x1;
        if ((d < x2) != (d < 0)) { px2[nn] = fx; py2[nn] = (py[zz]-py[z])*d/x2 + py[z]; nn++; }
        z = zz;
    }
    while (z);

    if (nn >= 3)
    {
        n = z = 0;
        do
        {
            double fy, y1, y2;
            int32_t zz = z+1; if (zz == nn) zz = 0;
            y1 = py2[z]; y2 = py2[zz]-y1; if ((cy1 <= y1) && (y1 <= cy2)) { py[n] = y1; px[n] = px2[z]; n++; }
            if (y2 <= 0) fy = cy2; else fy = cy1;  d = fy-y1;
            if ((d < y2) != (d < 0)) { py[n] = fy; px[n] = (px2[zz]-px2[z])*d/y2 + px2[z]; n++; }
            if (y2 <= 0) fy = cy1; else fy = cy2;  d = fy-y1;
            if ((d < y2) != (d < 0)) { py[n] = fy; px[n] = (px2[zz]-px2[z])*d/y2 + px2[z]; n++; }
            z = zz;
        }
        while (z);

#ifdef USE_OPENGL
        if (!nofog) bglDisable(GL_FOG);
        pow2xsplit = 0; drawpoly(px,py,n,method);
        if (!nofog) bglEnable(GL_FOG);
#else
        pow2xsplit = 0; drawpoly(px,py,n,method);
#endif
    }

#ifdef USE_OPENGL
    if (getrendermode() >= REND_POLYMOST)
    {
# ifdef POLYMER
        if (getrendermode() == REND_POLYMER) {
            r_detailmapping = olddetailmapping;
            r_glowmapping = oldglowmapping;
            polymer_postrotatesprite();
        }
# endif
        bglMatrixMode(GL_PROJECTION); bglPopMatrix();
        bglMatrixMode(GL_MODELVIEW); bglPopMatrix();
    }
#endif

    globalpicnum = ogpicnum;
    globalshade  = ogshade;
    globalpal    = ogpal;
    ghalfx       = oghalfx;
    grhalfxdown10 = ogrhalfxdown10;
    grhalfxdown10x = ogrhalfxdown10x;
    ghoriz       = oghoriz;
    frameoffset  = ofoffset;
    gchang = ogchang;
    gshang = ogshang;
    gctang = ogctang;
    gstang = ogstang;
}

#ifdef USE_OPENGL
static float trapextx[2];
static void drawtrap(float x0, float x1, float y0, float x2, float x3, float y1)
{
    float px[4], py[4];
    int32_t i, n;

    if (y0 == y1) return;
    px[0] = x0; py[0] = y0;  py[2] = y1;
    if (x0 == x1) { px[1] = x3; py[1] = y1; px[2] = x2; n = 3; }
    else if (x2 == x3) { px[1] = x1; py[1] = y0; px[2] = x3; n = 3; }
    else               { px[1] = x1; py[1] = y0; px[2] = x3; px[3] = x2; py[3] = y1; n = 4; }

    bglBegin(GL_TRIANGLE_FAN);
    for (i=0; i<n; i++)
    {
        px[i] = min(max(px[i],trapextx[0]),trapextx[1]);
        bglTexCoord2f(px[i]*gux + py[i]*guy + guo,
                      px[i]*gvx + py[i]*gvy + gvo);
        bglVertex2f(px[i],py[i]);
    }
    bglEnd();
}

static void tessectrap(const float *px, const float *py, const int32_t *point2, int32_t numpoints)
{
    float x0, x1, m0, m1;
    int32_t i, j, k, z, i0, i1, i2, i3, npoints, gap, numrst;

    static int32_t allocpoints = 0, *slist = 0, *npoint2 = 0;
    typedef struct { float x, y, xi; int32_t i; } raster;
    static raster *rst = 0;
    if (numpoints+16 > allocpoints) //16 for safety
    {
        allocpoints = numpoints+16;
        rst = (raster *)Brealloc(rst,allocpoints*sizeof(raster));
        slist = (int32_t *)Brealloc(slist,allocpoints*sizeof(int32_t));
        npoint2 = (int32_t *)Brealloc(npoint2,allocpoints*sizeof(int32_t));
    }

    //Remove unnecessary collinear points:
    for (i=0; i<numpoints; i++) npoint2[i] = point2[i];
    npoints = numpoints; z = 0;
    for (i=0; i<numpoints; i++)
    {
        j = npoint2[i]; if ((point2[i] < i) && (i < numpoints-1)) z = 3;
        if (j < 0) continue;
        k = npoint2[j];
        m0 = (px[j]-px[i])*(py[k]-py[j]);
        m1 = (py[j]-py[i])*(px[k]-px[j]);
        if (m0 < m1) { z |= 1; continue; }
        if (m0 > m1) { z |= 2; continue; }
        npoint2[i] = k; npoint2[j] = -1; npoints--; i--; //collinear
    }
    if (!z) return;
    trapextx[0] = trapextx[1] = px[0];
    for (i=j=0; i<numpoints; i++)
    {
        if (npoint2[i] < 0) continue;
        if (px[i] < trapextx[0]) trapextx[0] = px[i];
        if (px[i] > trapextx[1]) trapextx[1] = px[i];
        slist[j++] = i;
    }
    if (z != 3) //Simple polygon... early out
    {
        bglBegin(GL_TRIANGLE_FAN);
        for (i=0; i<npoints; i++)
        {
            j = slist[i];
            bglTexCoord2f(px[j]*gux + py[j]*guy + guo,
                          px[j]*gvx + py[j]*gvy + gvo);
            bglVertex2f(px[j],py[j]);
        }
        bglEnd();
        return;
    }

    //Sort points by y's
    for (gap=(npoints>>1); gap; gap>>=1)
        for (i=0; i<npoints-gap; i++)
            for (j=i; j>=0; j-=gap)
            {
                if (py[npoint2[slist[j]]] <= py[npoint2[slist[j+gap]]]) break;
                k = slist[j]; slist[j] = slist[j+gap]; slist[j+gap] = k;
            }

    numrst = 0;
    for (z=0; z<npoints; z++)
    {
        i0 = slist[z]; i1 = npoint2[i0]; if (py[i0] == py[i1]) continue;
        i2 = i1; i3 = npoint2[i1];
        if (py[i1] == py[i3]) { i2 = i3; i3 = npoint2[i3]; }

        //i0        i3
        //  \      /
        //   i1--i2
        //  /      \ ~
        //i0        i3

        if ((py[i1] < py[i0]) && (py[i2] < py[i3])) //Insert raster
        {
            for (i=numrst; i>0; i--)
            {
                if (rst[i-1].xi*(py[i1]-rst[i-1].y) + rst[i-1].x < px[i1]) break;
                rst[i+1] = rst[i-1];
            }
            numrst += 2;

            if (i&1) //split inside area
            {
                j = i-1;

                x0 = (py[i1] - rst[j  ].y)*rst[j  ].xi + rst[j  ].x;
                x1 = (py[i1] - rst[j+1].y)*rst[j+1].xi + rst[j+1].x;
                drawtrap(rst[j].x,rst[j+1].x,rst[j].y,x0,x1,py[i1]);
                rst[j  ].x = x0; rst[j  ].y = py[i1];
                rst[j+3].x = x1; rst[j+3].y = py[i1];
            }

            m0 = (px[i0]-px[i1]) / (py[i0]-py[i1]);
            m1 = (px[i3]-px[i2]) / (py[i3]-py[i2]);
            j = ((px[i1] > px[i2]) || ((i1 == i2) && (m0 >= m1))) + i;
            k = (i<<1)+1 - j;
            rst[j].i = i0; rst[j].xi = m0; rst[j].x = px[i1]; rst[j].y = py[i1];
            rst[k].i = i3; rst[k].xi = m1; rst[k].x = px[i2]; rst[k].y = py[i2];
        }
        else
        {
            //NOTE:don't count backwards!
            if (i1 == i2) { for (i=0; i<numrst; i++) if (rst[i].i == i1) break; }
            else { for (i=0; i<numrst; i++) if ((rst[i].i == i1) || (rst[i].i == i2)) break; }
            j = i&~1;

            if ((py[i1] > py[i0]) && (py[i2] > py[i3])) //Delete raster
            {
                for (; j<=i+1; j+=2)
                {
                    x0 = (py[i1] - rst[j  ].y)*rst[j  ].xi + rst[j  ].x;
                    if ((i == j) && (i1 == i2)) x1 = x0; else x1 = (py[i1] - rst[j+1].y)*rst[j+1].xi + rst[j+1].x;
                    drawtrap(rst[j].x,rst[j+1].x,rst[j].y,x0,x1,py[i1]);
                    rst[j  ].x = x0; rst[j  ].y = py[i1];
                    rst[j+1].x = x1; rst[j+1].y = py[i1];
                }
                numrst -= 2; for (; i<numrst; i++) rst[i] = rst[i+2];
            }
            else
            {
                x0 = (py[i1] - rst[j  ].y)*rst[j  ].xi + rst[j  ].x;
                x1 = (py[i1] - rst[j+1].y)*rst[j+1].xi + rst[j+1].x;
                drawtrap(rst[j].x,rst[j+1].x,rst[j].y,x0,x1,py[i1]);
                rst[j  ].x = x0; rst[j  ].y = py[i1];
                rst[j+1].x = x1; rst[j+1].y = py[i1];

                if (py[i0] < py[i3]) { rst[i].x = px[i2]; rst[i].y = py[i2]; rst[i].i = i3; }
                else { rst[i].x = px[i1]; rst[i].y = py[i1]; rst[i].i = i0; }
                rst[i].xi = (px[rst[i].i] - rst[i].x) / (py[rst[i].i] - py[i1]);
            }
        }
    }
}

void polymost_fillpolygon(int32_t npoints)
{
    pthtyp *pth;
    float f,a=0.0;
    int32_t i;

    globalx1 = mulscale16(globalx1,xyaspect);
    globaly2 = mulscale16(globaly2,xyaspect);
    gux = ((double)asm1)*(1.0/4294967296.0);
    gvx = ((double)asm2)*(1.0/4294967296.0);
    guy = ((double)globalx1)*(1.0/4294967296.0);
    gvy = ((double)globaly2)*(-1.0/4294967296.0);
    guo = (((double)xdim)*gux + ((double)ydim)*guy)*-.5 + ((double)globalposx)*(1.0/4294967296.0);
    gvo = (((double)xdim)*gvx + ((double)ydim)*gvy)*-.5 - ((double)globalposy)*(1.0/4294967296.0);

    //Convert int32_t to float (in-place)
    for (i=npoints-1; i>=0; i--)
    {
        ((float *)rx1)[i] = ((float)rx1[i])/4096.0;
        ((float *)ry1)[i] = ((float)ry1[i])/4096.0;
    }

    if (gloy1 != -1) setpolymost2dview(); //disables blending, texturing, and depth testing
    bglEnable(GL_ALPHA_TEST);
    bglEnable(GL_TEXTURE_2D);
    pth = texcache_fetch(globalpicnum,globalpal,getpalookup(globvis>>2, globalshade),0);
    bglBindTexture(GL_TEXTURE_2D, pth ? pth->glpic : 0);

    f = getshadefactor(globalshade);
    switch ((globalorientation>>7)&3)
    {
    case 0:
    case 1:
        a = 1.0f; bglDisable(GL_BLEND); break;
    case 2:
        a = 0.66f; bglEnable(GL_BLEND); break;
    case 3:
        a = 0.33f; bglEnable(GL_BLEND); break;
    }
    bglColor4f(f,f,f,a);

    tessectrap((float *)rx1,(float *)ry1,xb1,npoints);
}
#endif

int32_t polymost_drawtilescreen(int32_t tilex, int32_t tiley, int32_t wallnum, int32_t dimen, int32_t tilezoom,
                                int32_t usehitile, uint8_t *loadedhitile)
{
#ifdef USE_OPENGL
    float xdime, ydime, xdimepad, ydimepad, scx, scy, ratio = 1.0;
    int32_t i;
    pthtyp *pth;

    if (getrendermode() < REND_POLYMOST || !in3dmode()) return(-1);

    if (!glinfo.texnpot)
    {
        i = (1<<(picsiz[wallnum]&15)); if (i < tilesizx[wallnum]) i += i; xdimepad = (float)i;
        i = (1<<(picsiz[wallnum]>>4)); if (i < tilesizy[wallnum]) i += i; ydimepad = (float)i;
    }
    else
    {
        xdimepad = (float)tilesizx[wallnum];
        ydimepad = (float)tilesizy[wallnum];
    }
    xdime = (float)tilesizx[wallnum]; xdimepad = xdime/xdimepad;
    ydime = (float)tilesizy[wallnum]; ydimepad = ydime/ydimepad;

    if ((xdime <= dimen) && (ydime <= dimen))
    {
        scx = xdime;
        scy = ydime;
    }
    else
    {
        scx = (float)dimen;
        scy = (float)dimen;
        if (xdime < ydime)
            scx *= xdime/ydime;
        else
            scy *= ydime/xdime;
    }

    {
        int32_t ousehightile = usehightile;
        usehightile = usehitile && usehightile;
        pth = texcache_fetch(wallnum,0,0,4);
        if (usehightile)
            loadedhitile[wallnum>>3] |= (1<<(wallnum&7));
        usehightile = ousehightile;
    }

    bglBindTexture(GL_TEXTURE_2D, pth ? pth->glpic : 0);

    bglDisable(GL_ALPHA_TEST);

    if (tilezoom)
    {
        if (scx > scy) ratio = dimen/scx;
        else ratio = dimen/scy;
    }

    if (!pth || (pth->flags & 8))
    {
        bglDisable(GL_TEXTURE_2D);
        bglBegin(GL_TRIANGLE_FAN);
        if (gammabrightness)
            bglColor4f((float)curpalette[255].r/255.0,
                       (float)curpalette[255].g/255.0,
                       (float)curpalette[255].b/255.0,
                       1);
        else
            bglColor4f((float)britable[curbrightness][ curpalette[255].r ] / 255.0,
                       (float)britable[curbrightness][ curpalette[255].g ] / 255.0,
                       (float)britable[curbrightness][ curpalette[255].b ] / 255.0,
                       1);
        bglVertex2f((float)tilex            ,(float)tiley);
        bglVertex2f((float)tilex+(scx*ratio),(float)tiley);
        bglVertex2f((float)tilex+(scx*ratio),(float)tiley+(scy*ratio));
        bglVertex2f((float)tilex            ,(float)tiley+(scy*ratio));
        bglEnd();
    }

    bglColor4f(1,1,1,1);
    bglEnable(GL_TEXTURE_2D);
    bglEnable(GL_BLEND);
    bglBegin(GL_TRIANGLE_FAN);
    bglTexCoord2f(0,              0); bglVertex2f((float)tilex            ,(float)tiley);
    bglTexCoord2f(xdimepad,       0); bglVertex2f((float)tilex+(scx*ratio),(float)tiley);
    bglTexCoord2f(xdimepad,ydimepad); bglVertex2f((float)tilex+(scx*ratio),(float)tiley+(scy*ratio));
    bglTexCoord2f(0,       ydimepad); bglVertex2f((float)tilex            ,(float)tiley+(scy*ratio));
    bglEnd();

    return(0);
#else
    return -1;
#endif
}

static int32_t gen_font_glyph_tex(void)
{
    // construct a 256x128 8-bit alpha-only texture for the font glyph matrix
    char *tbuf, *cptr, *tptr;
    int32_t h,i,j;

    bglGenTextures(1,&polymosttext);
    if (!polymosttext) return -1;

    tbuf = (char *)Bmalloc(256*128);
    if (!tbuf)
    {
        bglDeleteTextures(1,&polymosttext);
        polymosttext = 0;
        return -1;
    }
    Bmemset(tbuf, 0, 256*128);

    cptr = (char *)textfont;
    for (h=0; h<256; h++)
    {
        tptr = tbuf + (h%32)*8 + (h/32)*256*8;
        for (i=0; i<8; i++)
        {
            for (j=0; j<8; j++)
            {
                if (cptr[h*8+i] & pow2char[7-j]) tptr[j] = 255;
            }
            tptr += 256;
        }
    }

    cptr = (char *)smalltextfont;
    for (h=0; h<256; h++)
    {
        tptr = tbuf + 256*64 + (h%32)*8 + (h/32)*256*8;
        for (i=1; i<7; i++)
        {
            for (j=2; j<6; j++)
            {
                if (cptr[h*8+i] & pow2char[7-j]) tptr[j-2] = 255;
            }
            tptr += 256;
        }
    }

    bglBindTexture(GL_TEXTURE_2D, polymosttext);
    bglTexImage2D(GL_TEXTURE_2D,0,GL_ALPHA,256,128,0,GL_ALPHA,GL_UNSIGNED_BYTE,(GLvoid *)tbuf);
    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
    Bfree(tbuf);

    return 0;
}

int32_t polymost_printext256(int32_t xpos, int32_t ypos, int16_t col, int16_t backcol, const char *name, char fontsize)
{
#ifndef USE_OPENGL
    return -1;
#else
    GLfloat tx, ty, txc, tyc;
    int32_t c;
    palette_t p,b;
    int32_t arbackcol = (unsigned)backcol < 256 ? backcol : 0;

    // FIXME?
    if (col < 0)
        col = 0;

    bricolor(&p, col);
    bricolor(&b, arbackcol);

    if (getrendermode() < REND_POLYMOST || !in3dmode()) return(-1);

    if (!polymosttext)
    {
        if (gen_font_glyph_tex() < 0)
            return -1;
    }
    else
    {
        bglBindTexture(GL_TEXTURE_2D, polymosttext);
    }

    setpolymost2dview();	// disables blending, texturing, and depth testing
    bglDisable(GL_ALPHA_TEST);
    bglDepthMask(GL_FALSE);	// disable writing to the z-buffer

    bglPushAttrib(GL_POLYGON_BIT|GL_ENABLE_BIT);
    // XXX: Don't fogify the OSD text in Mapster32 with r_usenewshading=2.
    bglDisable(GL_FOG);
    // We want to have readable text in wireframe mode, too:
    bglPolygonMode(GL_FRONT_AND_BACK, GL_FILL);

    if (backcol >= 0)
    {
        bglColor4ub(b.r,b.g,b.b,255);
        c = Bstrlen(name);

        bglBegin(GL_QUADS);
        bglVertex2i(xpos,ypos);
        bglVertex2i(xpos,ypos+(fontsize?6:8));
        bglVertex2i(xpos+(c<<(3-fontsize)),ypos+(fontsize?6:8));
        bglVertex2i(xpos+(c<<(3-fontsize)),ypos);
        bglEnd();
    }

    bglEnable(GL_TEXTURE_2D);
    bglEnable(GL_BLEND);
    bglColor4ub(p.r,p.g,p.b,255);
    txc = fontsize ? (4.0/256.0) : (8.0/256.0);
    tyc = fontsize ? (6.0/128.0) : (8.0/128.0);
    bglBegin(GL_QUADS);
    for (c=0; name[c]; c++)
    {
        if (name[c] == '^' && isdigit(name[c+1]))
        {
            char smallbuf[8];
            int32_t bi=0;
            while (isdigit(name[c+1]) && bi<3)
            {
                smallbuf[bi++]=name[c+1];
                c++;
            }
            smallbuf[bi++]=0;
            if (col)col = Batol(smallbuf);
            if ((unsigned)col >= 256)
                col = 0;

            bricolor(&p, col);

            bglColor4ub(p.r,p.g,p.b,255);
            continue;
        }
        tx = (float)(name[c]%32)/32.0;
        ty = (float)((name[c]/32) + (fontsize*8))/16.0;

        bglTexCoord2f(tx,ty);         bglVertex2i(xpos,ypos);
        bglTexCoord2f(tx+txc,ty);     bglVertex2i(xpos+(8>>fontsize),ypos);
        bglTexCoord2f(tx+txc,ty+tyc); bglVertex2i(xpos+(8>>fontsize),ypos+(fontsize?6:8));
        bglTexCoord2f(tx,ty+tyc);     bglVertex2i(xpos,ypos+(fontsize?6:8));

        xpos += (8>>fontsize);
    }
    bglEnd();

    bglDepthMask(GL_TRUE);	// re-enable writing to the z-buffer
    bglPopAttrib();

    return 0;
#endif
}

// Console commands by JBF
#ifdef USE_OPENGL
static int32_t gltexturemode(const osdfuncparm_t *parm)
{
    int32_t m;
    const char *p;

    if (parm->numparms != 1)
    {
        OSD_Printf("Current texturing mode is %s\n", glfiltermodes[gltexfiltermode].name);
        OSD_Printf("  Vaild modes are:\n");
        for (m = 0; m < NUMGLFILTERMODES; m++)
            OSD_Printf("     %d - %s\n", m, glfiltermodes[m].name);

        return OSDCMD_OK;
    }

    m = Bstrtoul(parm->parms[0], (char **)&p, 10);
    if (p == parm->parms[0])
    {
        // string
        for (m = 0; m < NUMGLFILTERMODES; m++)
        {
            if (!Bstrcasecmp(parm->parms[0], glfiltermodes[m].name))
                break;
        }

        if (m == NUMGLFILTERMODES)
            m = gltexfiltermode;   // no change
    }
    else
    {
        m = clamp(m, 0, NUMGLFILTERMODES-1);
    }

    gltexfiltermode = m;
    gltexapplyprops();

    OSD_Printf("Texture filtering mode changed to %s\n", glfiltermodes[gltexfiltermode].name);

    return OSDCMD_OK;
}
#endif

static int32_t osdcmd_cvar_set_polymost(const osdfuncparm_t *parm)
{
    int32_t r = osdcmd_cvar_set(parm);

    if (xdim == 0 || ydim == 0 || bpp == 0) // video not set up yet
    {
        if (r == OSDCMD_OK)
        {
#ifdef POLYMER
            if (!Bstrcasecmp(parm->name, "r_pr_maxlightpasses"))
            {
                pr_maxlightpasses = r_pr_maxlightpasses;
                return r;
            }
#endif
        }

        return r;
    }

#ifdef USE_OPENGL
    if (r == OSDCMD_OK)
    {
        if (!Bstrcasecmp(parm->name, "r_swapinterval"))
        {
            setvsync(vsync);
            return r;
        }
        else if (!Bstrcasecmp(parm->name, "r_downsize"))
        {
            if (r_downsize != r_downsizevar && r_downsizevar != -1)
            {
                texcache_invalidate();
                resetvideomode();
                if (setgamemode(fullscreen,xdim,ydim,bpp))
                    OSD_Printf("restartvid: Reset failed...\n");
            }
            else r_downsizevar = r_downsize;

            return r;
        }
        else if (!Bstrcasecmp(parm->name, "r_textureanisotropy"))
        {
            gltexapplyprops();
            return r;
        }
        else if (!Bstrcasecmp(parm->name, "r_texturemode"))
        {
            gltexturemode(parm);
            return r;
        }
#ifdef POLYMER
        else if (!Bstrcasecmp(parm->name, "r_pr_maxlightpasses"))
        {
            if (pr_maxlightpasses != r_pr_maxlightpasses)
            {
                polymer_invalidatelights();
                pr_maxlightpasses = r_pr_maxlightpasses;
            }
            return r;
        }
#endif
    }
#endif
    return r;
}

void polymost_initosdfuncs(void)
{
    uint32_t i;

    cvar_t cvars_polymost[] =
    {
#ifdef USE_OPENGL
        { "r_animsmoothing","enable/disable model animation smoothing",(void *) &r_animsmoothing, CVAR_BOOL, 0, 1 },
        { "r_detailmapping","enable/disable detail mapping",(void *) &r_detailmapping, CVAR_BOOL, 0, 1 },
        { "r_downsize","controls downsizing factor (quality) for hires textures",(void *) &r_downsize, CVAR_INT|CVAR_FUNCPTR, 0, 5 },
        { "r_fullbrights","enable/disable fullbright textures",(void *) &r_fullbrights, CVAR_BOOL, 0, 1 },
        { "r_glowmapping","enable/disable glow mapping",(void *) &r_glowmapping, CVAR_BOOL, 0, 1 },
        /*
          { "r_multisample","sets the number of samples used for antialiasing (0 = off)",(void *)&glmultisample, CVAR_BOOL, 0, 1 },
          { "r_nvmultisamplehint","enable/disable Nvidia multisampling hinting",(void *)&glnvmultisamplehint, CVAR_BOOL, 0, 1 },
        */
        {
            "r_parallaxskyclamping","enable/disable parallaxed floor/ceiling sky texture clamping",
            (void *) &r_parallaxskyclamping, CVAR_BOOL, 0, 1
        },
        {
            "r_parallaxskypanning","enable/disable parallaxed floor/ceiling panning when drawing a parallaxed sky",
            (void *) &r_parallaxskypanning, CVAR_BOOL, 0, 1
        },
        { "r_polygonmode","debugging feature",(void *) &glpolygonmode, CVAR_INT | CVAR_NOSAVE, 0, 3 },
        { "r_redbluemode","enable/disable experimental OpenGL red-blue glasses mode",(void *) &glredbluemode, CVAR_BOOL, 0, 1 },
        { "r_shadescale","multiplier for shading",(void *) &shadescale, CVAR_FLOAT, 0, 10 },
        { "r_shadescale_unbounded","enable/disable allowance of complete blackness",(void *) &shadescale_unbounded, CVAR_BOOL, 0, 1 },
        { "r_swapinterval","sets the GL swap interval (VSync)",(void *) &vsync, CVAR_INT|CVAR_FUNCPTR, -1, 1 },
        { "r_texcache","enable/disable OpenGL compressed texture cache",(void *) &glusetexcache, CVAR_INT, 0, 2 },
        { "r_memcache","enable/disable texture cache memory cache",(void *) &glusememcache, CVAR_BOOL, 0, 1 },
        { "r_texcompr","enable/disable OpenGL texture compression",(void *) &glusetexcompr, CVAR_BOOL, 0, 1 },
        { "r_textureanisotropy", "changes the OpenGL texture anisotropy setting", (void *) &glanisotropy, CVAR_INT|CVAR_FUNCPTR, 0, 16 },
        { "r_texturemaxsize","changes the maximum OpenGL texture size limit",(void *) &gltexmaxsize, CVAR_INT | CVAR_NOSAVE, 0, 4096 },
        { "r_texturemiplevel","changes the highest OpenGL mipmap level used",(void *) &gltexmiplevel, CVAR_INT, 0, 6 },
        { "r_texturemode", "changes the texture filtering settings", (void *) &gltexfiltermode, CVAR_INT|CVAR_FUNCPTR, 0, 5 },
        { "r_usenewshading", "visibility code: 0: Polymost, 2: Classic", (void *) &r_usenewshading, CVAR_INT, 0, 2 },
        { "r_usetileshades", "enable/disable Polymost tile shade textures", (void *) &r_usetileshades, CVAR_BOOL | CVAR_INVALIDATEART, 0, 1 },
        { "r_vbocount","sets the number of Vertex Buffer Objects to use when drawing models",(void *) &r_vbocount, CVAR_INT, 1, 256 },
        { "r_vbos"," enable/disable using Vertex Buffer Objects when drawing models",(void *) &r_vbos, CVAR_BOOL, 0, 1 },
        { "r_vertexarrays","enable/disable using vertex arrays when drawing models",(void *) &r_vertexarrays, CVAR_BOOL, 0, 1 },
        { "r_anamorphic", "enable/disable widescreen mode", (void *) &glwidescreen, CVAR_BOOL, 0, 1 },
        { "r_projectionhack", "enable/disable projection hack", (void *) &glprojectionhacks, CVAR_INT, 0, 2 },

#ifdef POLYMER
        // polymer cvars
        { "r_pr_lighting", "enable/disable dynamic lights - restarts renderer", (void *) &pr_lighting, CVAR_BOOL | CVAR_RESTARTVID, 0, 1 },
        { "r_pr_normalmapping", "enable/disable virtual displacement mapping", (void *) &pr_normalmapping, CVAR_BOOL, 0, 1 },
        { "r_pr_specularmapping", "enable/disable specular mapping", (void *) &pr_specularmapping, CVAR_BOOL, 0, 1 },
        { "r_pr_shadows", "enable/disable dynamic shadows", (void *) &pr_shadows, CVAR_BOOL, 0, 1 },
        { "r_pr_shadowcount", "maximal amount of shadow emitting lights on screen - you need to restart the renderer for it to take effect", (void *) &pr_shadowcount, CVAR_INT, 0, 64 },
        { "r_pr_shadowdetail", "sets the shadow map resolution - you need to restart the renderer for it to take effect", (void *) &pr_shadowdetail, CVAR_INT, 0, 5 },
        { "r_pr_shadowfiltering", "enable/disable shadow edges filtering - you need to restart the renderer for it to take effect", (void *) &pr_shadowfiltering, CVAR_BOOL, 0, 1 },
        { "r_pr_maxlightpasses", "the maximal amount of lights a single object can by affected by", (void *) &r_pr_maxlightpasses, CVAR_INT|CVAR_FUNCPTR, 0, PR_MAXLIGHTS },
        { "r_pr_maxlightpriority", "lowering that value removes less meaningful lights from the scene", (void *) &pr_maxlightpriority, CVAR_INT, 0, PR_MAXLIGHTPRIORITY },
        { "r_pr_fov", "sets the field of vision in build angle", (void *) &pr_fov, CVAR_INT, 0, 1023},
        { "r_pr_customaspect", "if non-zero, forces the 3D view aspect ratio", (void *) &pr_customaspect, CVAR_DOUBLE, 0, 3 },
        { "r_pr_billboardingmode", "face sprite display method. 0: classic mode; 1: polymost mode", (void *) &pr_billboardingmode, CVAR_INT, 0, 1 },
        { "r_pr_verbosity", "verbosity level of the polymer renderer", (void *) &pr_verbosity, CVAR_INT, 0, 3 },
        { "r_pr_wireframe", "toggles wireframe mode", (void *) &pr_wireframe, CVAR_INT | CVAR_NOSAVE, 0, 1 },
        { "r_pr_vbos", "contols Vertex Buffer Object usage. 0: no VBOs. 1: VBOs for map data. 2: VBOs for model data.", (void *) &pr_vbos, CVAR_INT | CVAR_RESTARTVID, 0, 2 },
        { "r_pr_gpusmoothing", "toggles model animation interpolation", (void *) &pr_gpusmoothing, CVAR_INT, 0, 1 },
        { "r_pr_overrideparallax", "overrides parallax mapping scale and bias values with values from the pr_parallaxscale and pr_parallaxbias cvars; use it to fine-tune DEF tokens", (void *) &pr_overrideparallax, CVAR_BOOL | CVAR_NOSAVE, 0, 1 },
        { "r_pr_parallaxscale", "overriden parallax mapping offset scale", (void *) &pr_parallaxscale, CVAR_FLOAT | CVAR_NOSAVE, -10, 10 },
        { "r_pr_parallaxbias", "overriden parallax mapping offset bias", (void *) &pr_parallaxbias, CVAR_FLOAT | CVAR_NOSAVE, -10, 10 },
        { "r_pr_overridespecular", "overrides specular material power and factor values with values from the pr_specularpower and pr_specularfactor cvars; use it to fine-tune DEF tokens", (void *) &pr_overridespecular, CVAR_BOOL | CVAR_NOSAVE, 0, 1 },
        { "r_pr_specularpower", "overriden specular material power", (void *) &pr_specularpower, CVAR_FLOAT | CVAR_NOSAVE, -10, 1000 },
        { "r_pr_specularfactor", "overriden specular material factor", (void *) &pr_specularfactor, CVAR_FLOAT | CVAR_NOSAVE, -10, 1000 },
        { "r_pr_highpalookups", "enable/disable highpalookups", (void *) &pr_highpalookups, CVAR_BOOL, 0, 1 },
        { "r_pr_artmapping", "enable/disable art mapping", (void *) &pr_artmapping, CVAR_BOOL | CVAR_INVALIDATEART, 0, 1 },
        { "r_pr_overridehud", "overrides hud model parameters with values from the pr_hud* cvars; use it to fine-tune DEF tokens", (void *) &pr_overridehud, CVAR_BOOL | CVAR_NOSAVE, 0, 1 },
        { "r_pr_hudxadd", "overriden HUD xadd; see r_pr_overridehud", (void *) &pr_hudxadd, CVAR_FLOAT | CVAR_NOSAVE, -100, 100 },
        { "r_pr_hudyadd", "overriden HUD yadd; see r_pr_overridehud", (void *) &pr_hudyadd, CVAR_FLOAT | CVAR_NOSAVE, -100, 100 },
        { "r_pr_hudzadd", "overriden HUD zadd; see r_pr_overridehud", (void *) &pr_hudzadd, CVAR_FLOAT | CVAR_NOSAVE, -100, 100 },
        { "r_pr_hudangadd", "overriden HUD angadd; see r_pr_overridehud", (void *) &pr_hudangadd, CVAR_INT | CVAR_NOSAVE, -512, 512 },
        { "r_pr_hudfov", "overriden HUD fov; see r_pr_overridehud", (void *) &pr_hudfov, CVAR_INT | CVAR_NOSAVE, 0, 1023 },
        { "r_pr_overridemodelscale", "overrides model scale if non-zero; use it to fine-tune DEF tokens", (void *) &pr_overridemodelscale, CVAR_FLOAT | CVAR_NOSAVE, 0, 500 },
        { "r_pr_ati_fboworkaround", "enable this to workaround an ATI driver bug that causes sprite shadows to be square - you need to restart the renderer for it to take effect", (void *) &pr_ati_fboworkaround, CVAR_BOOL | CVAR_NOSAVE, 0, 1 },
        { "r_pr_ati_nodepthoffset", "enable this to workaround an ATI driver bug that causes sprite drawing to freeze the game on Radeon X1x00 hardware - you need to restart the renderer for it to take effect", (void *) &pr_ati_nodepthoffset, CVAR_BOOL | CVAR_NOSAVE, 0, 1 },
#endif

        { "r_models","enable/disable model rendering",(void *) &usemodels, CVAR_BOOL, 0, 1 },
        { "r_hightile","enable/disable hightile texture rendering",(void *) &usehightile, CVAR_BOOL, 0, 1 },

        { "r_preview_mouseaim", "toggles mouse aiming preview, use this to calibrate yxaspect in Polymost Mapster32", (void *) &preview_mouseaim, CVAR_BOOL, 0, 1 },
#endif
    };

    for (i=0; i<sizeof(cvars_polymost)/sizeof(cvars_polymost[0]); i++)
    {
        // can't do this: editstatus is set after this function
//        if (editstatus==0 && !Bstrcmp(cvars_polymost[i].name, "r_preview_mouseaim"))
//            continue;

        if (OSD_RegisterCvar(&cvars_polymost[i]))
            continue;

        OSD_RegisterFunction(cvars_polymost[i].name, cvars_polymost[i].desc,
                             cvars_polymost[i].type & CVAR_FUNCPTR ? osdcmd_cvar_set_polymost : osdcmd_cvar_set);
    }
}

void polymost_precache(int32_t dapicnum, int32_t dapalnum, int32_t datype)
{
#ifdef USE_OPENGL
    // dapicnum and dapalnum are like you'd expect
    // datype is 0 for a wall/floor/ceiling and 1 for a sprite
    //    basically this just means walls are repeating
    //    while sprites are clamped
    int32_t mid;

    if (getrendermode() < REND_POLYMOST) return;

    if ((palookup[dapalnum] == NULL) && (dapalnum < (MAXPALOOKUPS - RESERVEDPALS))) return;//dapalnum = 0;

    //OSD_Printf("precached %d %d type %d\n", dapicnum, dapalnum, datype);
    hicprecaching = 1;


    texcache_fetch(dapicnum, dapalnum, 0, (datype & 1) << 2);
    hicprecaching = 0;

    if (datype == 0 || !usemodels) return;

    mid = md_tilehasmodel(dapicnum,dapalnum);
    if (mid < 0 || models[mid]->mdnum < 2) return;

    {
        int32_t i,j=0;

        if (models[mid]->mdnum == 3)
            j = ((md3model_t *)models[mid])->head.numsurfs;

        for (i=0; i<=j; i++)
            mdloadskin((md2model_t *)models[mid], 0, dapalnum, i);
    }
#endif
}

#else /* if !defined USE_OPENGL */

#include "compat.h"

int32_t polymost_drawtilescreen(int32_t tilex, int32_t tiley, int32_t wallnum, int32_t dimen,
                                int32_t usehitile, uint8_t *loadedhitile)
{
    UNREFERENCED_PARAMETER(tilex);
    UNREFERENCED_PARAMETER(tiley);
    UNREFERENCED_PARAMETER(wallnum);
    UNREFERENCED_PARAMETER(dimen);
    UNREFERENCED_PARAMETER(usehitile);
    UNREFERENCED_PARAMETER(loadedhitile);
    return -1;
}

#endif

// vim:ts=4:sw=4:
