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OgreGLHardwareOcclusionQuery.h

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00001 /*
00002 -----------------------------------------------------------------------------
00003 This source file is part of OGRE
00004     (Object-oriented Graphics Rendering Engine)
00005 For the latest info, see http://ogre.sourceforge.net/
00006 
00007 Copyright © 2000-2003 The OGRE Team
00008 Also see acknowledgements in Readme.html
00009 
00010 This program is free software; you can redistribute it and/or modify it under
00011 the terms of the GNU Lesser General Public License as published by the Free Software
00012 Foundation; either version 2 of the License, or (at your option) any later
00013 version.
00014 
00015 This program is distributed in the hope that it will be useful, but WITHOUT
00016 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
00017 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
00018 
00019 You should have received a copy of the GNU Lesser General Public License along with
00020 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
00021 Place - Suite 330, Boston, MA 02111-1307, USA, or go to
00022 http://www.gnu.org/copyleft/lesser.txt.
00023 -----------------------------------------------------------------------------
00024 */
00025 
00026 /*
00027 The nVidia occlusion query extension is defined in glext.h so you don't 
00028 need anything else. You do need to look up the function, we provide a 
00029 GLSupport class to do this, which has platform implementations for 
00030 getProcAddress. Check the way that extensions like glActiveTextureARB are 
00031 initialised and used in glRenderSystem and copy what is done there.
00032 
00033 
00034 
00035   To do: fix so dx7 and DX9 checks and flags if HW Occlusion is supported
00036   See the openGl dito for ideas what to do.
00037 
00038 */
00039 
00040 
00041 
00042 //GL_ActiveTextureARB_Func* glActiveTextureARB_ptr = (GL_ActiveTextureARB_Func)mGLSupport->getProcAddress("glActiveTextureARB");
00043 
00044 #ifndef __GLHARDWAREOCCLUSIONQUERY_H__
00045 #define __GLHARDWAREOCCLUSIONQUERY_H__
00046 
00047 #include "OgreGLPrerequisites.h"
00048 #include "OgreHardwareOcclusionQuery.h"
00049 
00050 
00051 namespace Ogre { 
00052 
00053 
00054 // If you use multiple rendering passes you can test only the first pass and all other passes don't have to be rendered 
00055 // if the first pass resultet has too few pixels visable.
00056 
00057 // Be sure to render all occlluder first and whats out so the RenderQue don't switch places on 
00058 // the occluding objects and the tested objects because it thinks it's more effective..
00059 
00060 
00068 class GLHardwareOcclusionQuery : public HardwareOcclusionQuery
00069 {
00070 //----------------------------------------------------------------------
00071 // Public methods
00072 //--
00073 public:
00078     GLHardwareOcclusionQuery();
00082     ~GLHardwareOcclusionQuery();
00083 
00084     //------------------------------------------------------------------
00085     // Occlusion query functions (see base class documentation for this)
00086     //--
00087 
00088     void beginOcclusionQuery();
00089     void endOcclusionQuery();
00090     bool pullOcclusionQuery( unsigned int* NumOfFragments);
00091     bool pullOcclusionQuery( unsigned int* NumOfFragments, const HW_OCCLUSIONQUERY flag  ); 
00092     unsigned int getLastQuerysPixelcount() { return m_uintPixelCount; }
00093 
00094     // This functions are optional, it's a simple filter that simply skipps some hardware occlusion tests on visable objects only
00095     // It's easy to use if you don't have to keep track on which objects are visable (can be skipped) and what objects arn't visable..
00096     // (None visable objects and object you introduce for the first time have allways to be tested allthough the cheepest possible 
00097     // LOD (Level Of Detail) mesh and material wize). 
00098 
00109     void setSkipRate( int skip ) { m_Skip = skip; }     // Using 2 only 50 % of the tests are actully made and 3 results in only 33% of the tests. So on.
00110     int  getSkipRate() { return m_Skip; } 
00111 
00112 
00113 //----------------------------------------------------------------------
00114 // Protected members
00115 //--
00116 protected:
00117 
00118     unsigned int    m_uintPixelCount;
00119     unsigned int    m_uintQuery[1];
00120     bool            m_bOcclusionQuery;
00121     int             m_SkipCounter;      // m_SkipConter =  m_SkipConter % m_Skip; if ( m_SkipConter == 0 && m_uintPixelCount !=0 ) TestHWOcclusion else just return 
00122     static int      m_Skip;             // This is shared by all instancies
00123     bool            m_bHWOcclusionSupport;
00124 };
00125 
00126 
00127 }
00128 
00129 #endif 
00130 

Copyright © 2002-2003 by The OGRE Team
Last modified Sun Nov 28 19:48:25 2004