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/*!
  \class SoColorIndex SoColorIndex.h Inventor/nodes/SoColorIndex.h
  \brief The SoColorIndex class is used to specify color indices for subsequent shapes.
  \ingroup nodes

  This node should only be used in OpenGL color-index mode, and only
  when the current light model is set to SoLightModel::BASE_COLOR.

  OpenGL colorindex mode is where the colors for individual pixels are
  fetched from a color lookup table ("CLUT"). The usual thing to do is
  to set up a canvas in RGBA truecolor mode.

  One common use for colorindex mode OpenGL canvases is to use one in
  the overlay planes (which are usually limited to only 2 or 4
  available colors), if supported by the OpenGL hardware and / or
  driver.

  <b>FILE FORMAT/DEFAULTS:</b>
  \code
    ColorIndex {
        index 1
    }
  \endcode
*/

// FIXME: couldn't we check for the above mentioned pre-conditions
// (colorindex mode, SoLightModel::BASE_COLOR) and assert() or
// SoDebugError::post() if any of the two is not met?
//
// UPDATE: use glGetBooleanv(GL_RGBA_MODE, ...) or
// SoGLColorIndexElement::isColorIndexMode() for the color-index
// mode-check.
//
// 20010809 mortene.

#include <Inventor/nodes/SoColorIndex.h>

#include <Inventor/elements/SoOverrideElement.h>
#include <Inventor/elements/SoGLColorIndexElement.h>
#include <Inventor/actions/SoGLRenderAction.h>

#include "nodes/SoSubNodeP.h"

/*!
  \var SoMFInt32 SoColorIndex::index
  Color indices which can be used by shapes.
*/

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

SO_NODE_SOURCE(SoColorIndex);

/*!
  Constructor.
*/
SoColorIndex::SoColorIndex()
{
  SO_NODE_INTERNAL_CONSTRUCTOR(SoColorIndex);

  SO_NODE_ADD_FIELD(index, (1));
}

/*!
  Destructor.
*/
SoColorIndex::~SoColorIndex()
{
}

// doc in parent
void
SoColorIndex::initClass(void)
{
  SO_NODE_INTERNAL_INIT_CLASS(SoColorIndex, SO_FROM_INVENTOR_1);

  SO_ENABLE(SoGLRenderAction, SoGLColorIndexElement);
}

// doc in parent
void
SoColorIndex::GLRender(SoGLRenderAction * action)
{
  SoState * state = action->getState();
  if (!this->index.isIgnored() &&
      !SoOverrideElement::getColorIndexOverride(state)) {
    if (this->isOverride()) {
      SoOverrideElement::setColorIndexOverride(state, this, TRUE);
    }
    SoGLColorIndexElement::set(state, this,
                               this->index.getNum(),
                               this->index.getValues(0));
  }
}
