Function vtkOpenGLImageMapperRenderChar

Rendering/OpenGL2/vtkOpenGLImageMapper.cxx:382–507

template <class T>
void vtkOpenGLImageMapperRenderChar(
  vtkOpenGLImageMapper* self, vtkImageData* data, T* dataPtr, vtkViewport* viewport)
{
  vtkOpenGLClearErrorMacro();

  int inMin0 = self->DisplayExtent[0];
  int inMax0 = self->DisplayExtent[1];
  int inMin1 = self->DisplayExtent[2];
  int inMax1 = self->DisplayExtent[3];

  int width = inMax0 - inMin0 + 1;
  int height = inMax1 - inMin1 + 1;

  vtkIdType tempIncs[3];
  data->GetIncrements(tempIncs);
  vtkIdType inInc1 = tempIncs[1];

  int bpp = data->GetPointData()->GetScalars()->GetNumberOfComponents();

  double range[2];
  data->GetPointData()->GetScalars()->GetDataTypeRange(range);

  auto ostate = static_cast<vtkOpenGLRenderWindow*>(viewport->GetVTKWindow())->GetState();
  ostate->vtkglPixelStorei(GL_UNPACK_ALIGNMENT, 1);

  //
  if (bpp == 3)
  { // feed through RGB bytes without reformatting
    if (inInc1 != width * bpp)
    {
      ostate->vtkglPixelStorei(GL_UNPACK_ROW_LENGTH, inInc1 / bpp);
    }
    self->DrawPixels(viewport, width, height, 3, static_cast<void*>(dataPtr));
  }
  else if (bpp == 4)
  { // feed through RGBA bytes without reformatting
    if (inInc1 != width * bpp)
    {
      ostate->vtkglPixelStorei(GL_UNPACK_ROW_LENGTH, inInc1 / bpp);
    }
    self->DrawPixels(viewport, width, height, 4, static_cast<void*>(dataPtr));
  }
  else
  { // feed through other bytes without reformatting
    T* inPtr = dataPtr;
    T* inPtr1 = inPtr;
    unsigned char tmp;

    int i;
    int j = height;

    unsigned char* newPtr;
    int nC = 4;
    if (bpp == 1 || bpp == 3)
    {
      nC = 3;
    }
    if (nC == 3)