void VariableManager::beginRenderPass(GLRenderState& renderState) const
{
/* Get the context data item: */
DataItem* dataItem=renderState.getContextData().retrieveDataItem<DataItem>(this);
/* Initialize the scalar variable tracker: */
dataItem->lastBoundScalarVariableIndex=-1;
/* Save the OpenGL texture matrix: */
renderState.setMatrixMode(2);
glPushMatrix();
dataItem->textureMatrixVersion=renderState.getMatrixVersion();
}
void VariableManager::bindColorMap(int scalarVariableIndex,GLRenderState& renderState) const
{
/* Get the context data item: */
DataItem* dataItem=renderState.getContextData().retrieveDataItem<DataItem>(this);
/* Set up 1D texture mapping: */
renderState.setTextureLevel(1);
/* Bind the color texture object: */
renderState.bindTexture(dataItem->colorMapTextureIds[scalarVariableIndex]);
/* Check if the texture object is outdated: */
const ScalarVariable& sv=scalarVariables[scalarVariableIndex];
if(dataItem->colorMapVersions[scalarVariableIndex]!=sv.colorMapVersion)
{
/* Set the texture object's parameters: */
glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_BASE_LEVEL,0);
glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_MAX_LEVEL,0);
glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
/* Upload the changed color map into the texture object: */
glPixelStorei(GL_UNPACK_SKIP_PIXELS,0);
glPixelStorei(GL_UNPACK_ALIGNMENT,1);
glTexImage1D(GL_TEXTURE_1D,0,GL_RGBA8,256,0,GL_RGBA,GL_FLOAT,sv.colorMap->getColors());
/* Mark the texture object as up-to-date: */
dataItem->colorMapVersions[scalarVariableIndex]=sv.colorMapVersion;
}
/* Set up the texture matrix to convert scalar variable values to color map indices: */
renderState.setMatrixMode(2);
if(dataItem->lastBoundScalarVariableIndex!=scalarVariableIndex||dataItem->textureMatrixVersion!=renderState.getMatrixVersion())
{
glLoadIdentity();
double mapMin=double(sv.colorMapRange.first);
double mapRange=double(sv.colorMapRange.second)-mapMin;
glScaled(1.0/mapRange,1.0,1.0);
glTranslated(-mapMin,0.0,0.0);
renderState.updateMatrix();
/* Mark the texture matrix as up to date: */
dataItem->lastBoundScalarVariableIndex=scalarVariableIndex;
dataItem->textureMatrixVersion=renderState.getMatrixVersion();
}
}