Method CompositeFunction

Rendering/Volume/vtkUnstructuredGridVolumeZSweepMapper.cxx:4061–4233

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//------------------------------------------------------------------------------
void vtkUnstructuredGridVolumeZSweepMapper::CompositeFunction(double zTarget)
{
  int y = this->YBounds[0];
  vtkIdType i = y * this->ImageInUseSize[0] + this->XBounds[0];

  vtkIdType index = (y * this->ImageMemorySize[0] + this->XBounds[0]) << 2; // *4
  vtkIdType indexStep = this->ImageMemorySize[0] << 2;                      // *4

  vtkPixelListEntry* current;
  vtkPixelListEntry* next;
  double zBuffer = 0;

  int newXBounds[2];
  int newYBounds[2];

  newXBounds[0] = this->ImageInUseSize[0];
  newXBounds[1] = 0;
  newYBounds[0] = this->ImageInUseSize[1];
  newYBounds[1] = 0;

  int xMin = this->XBounds[0];
  int xMax = this->XBounds[1];
  int yMax = this->YBounds[1];

  vtkPixelList* pixel;
  int x;
  vtkIdType j;
  vtkIdType index2;
  int done;
  int doIntegration;
  double length;
  float* color;

  // for each pixel in the bounding box
  while (y <= yMax)
  {
    x = xMin;
    j = i;
    index2 = index;
    while (x <= xMax)
    {
      pixel = this->PixelListFrame->GetList(j);
      // we need at least two entries per pixel to perform compositing
      if (pixel->GetSize() >= 2)
      {
        current = pixel->GetFirst();
        next = current->GetNext();
#ifdef BACK_TO_FRONT
        done = current->GetZview() <= zTarget || next->GetZview() <= zTarget;
#else
        done = current->GetZview() >= zTarget || next->GetZview() >= zTarget;
#endif

        if (!done && this->ZBuffer != nullptr)
        {
          // value of the z buffer at the current pixel.
          zBuffer = this->GetZBufferValue(x, y);
        }