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/*!
  \class SoNormal SoNormal.h Inventor/nodes/SoNormal.h
  \brief The SoNormal class is a node for providing normals to the state.
  \ingroup nodes

  Coin will automatically calculate normals for you if no SoNormal
  nodes are present in the scene graph, but explicitly setting normals
  is useful for at least two purposes: 1) a potential increase in
  performance, 2) you can calculate and use "incorrect" normals to do
  various special effects.

  <b>FILE FORMAT/DEFAULTS:</b>
  \code
    Normal {
        vector [  ]
    }
  \endcode

  \sa SoNormalBinding
*/

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

#include <Inventor/nodes/SoNormal.h>

#include <Inventor/actions/SoCallbackAction.h>
#include <Inventor/actions/SoGLRenderAction.h>
#include <Inventor/actions/SoGetPrimitiveCountAction.h>
#include <Inventor/actions/SoPickAction.h>
#include <Inventor/elements/SoNormalElement.h>
#include <Inventor/elements/SoOverrideElement.h>
#include <Inventor/elements/SoGLVBOElement.h>

#include "nodes/SoSubNodeP.h"
#include "rendering/SoVBO.h"

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

/*!
  \var SoMFVec3f SoNormal::vector
  Sets a pool of normal vectors in the traversal state.
*/

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

class SoNormalP {
 public:
  SoNormalP() : vbo(NULL) { }
  ~SoNormalP() { delete this->vbo; }

  SoVBO * vbo;
};

#define PRIVATE(obj) obj->pimpl

SO_NODE_SOURCE(SoNormal);

/*!
  Constructor.
*/
SoNormal::SoNormal(void)
{
  PRIVATE(this) = new SoNormalP;
  SO_NODE_INTERNAL_CONSTRUCTOR(SoNormal);

  SO_NODE_ADD_FIELD(vector, (NULL));
}

/*!
  Destructor.
*/
SoNormal::~SoNormal()
{
  delete PRIVATE(this);
}

// Doc in superclass.
void
SoNormal::initClass(void)
{
  SO_NODE_INTERNAL_INIT_CLASS(SoNormal, SO_FROM_INVENTOR_1|SoNode::VRML1);

  SO_ENABLE(SoCallbackAction, SoNormalElement);
  SO_ENABLE(SoGLRenderAction, SoNormalElement);
  SO_ENABLE(SoGetPrimitiveCountAction, SoNormalElement);
  SO_ENABLE(SoPickAction, SoNormalElement);
}

// Doc in superclass.
void
SoNormal::GLRender(SoGLRenderAction * action)
{
  //
  // FIXME: code to test if all normals are unit length, and store
  // this in some cached variable.  should be passed on to
  // SoGLNormalizeElement to optimize rendering (pederb)
  //
  SoNormal::doAction(action);
  SoState * state = action->getState();
  
  SoBase::staticDataLock();
  SbBool setvbo = FALSE;
  const int num = this->vector.getNum();
  if (SoGLVBOElement::shouldCreateVBO(state, num)) {
    setvbo = TRUE;
    SbBool dirty = FALSE;
    if (PRIVATE(this)->vbo == NULL) {
      PRIVATE(this)->vbo = new SoVBO(GL_ARRAY_BUFFER, GL_STATIC_DRAW); 
      dirty =  TRUE;
    }
    else if (PRIVATE(this)->vbo->getBufferDataId() != this->getNodeId()) {
      dirty = TRUE;
    }
    if (dirty) {
      PRIVATE(this)->vbo->setBufferData(this->vector.getValues(0),
                                        num*sizeof(SbVec3f),
                                        this->getNodeId());
    }
  }
  else if (PRIVATE(this)->vbo && PRIVATE(this)->vbo->getBufferDataId()) {
    // clear buffers to deallocate VBO memory
    PRIVATE(this)->vbo->setBufferData(NULL, 0, 0);
  }
  SoBase::staticDataUnlock();
  SoGLVBOElement::setNormalVBO(state, setvbo? PRIVATE(this)->vbo : NULL);
}

// Doc in superclass.
void
SoNormal::doAction(SoAction * action)
{
  SoState * state = action->getState();
  if (!this->vector.isIgnored() &&
      !SoOverrideElement::getNormalVectorOverride(state)) {
    SoNormalElement::set(state, this,
                         this->vector.getNum(), this->vector.getValues(0));
    if (this->isOverride()) {
      SoOverrideElement::setNormalVectorOverride(state, this, TRUE);
    }
  }
}

// Doc in superclass.
void
SoNormal::callback(SoCallbackAction * action)
{
  SoNormal::doAction(action);
}

// Doc in superclass.
void
SoNormal::pick(SoPickAction * action)
{
  SoNormal::doAction(action);
}

// Doc in superclass.
void
SoNormal::getPrimitiveCount(SoGetPrimitiveCountAction * action)
{
  SoNormal::doAction(action);
}

#undef PRIVATE
