Function vtkOpenGLImageMapperRenderDouble

Rendering/OpenGL2/vtkOpenGLImageMapper.cxx:145–245

template <class T>
void vtkOpenGLImageMapperRenderDouble(vtkOpenGLImageMapper* self, vtkImageData* data, T* dataPtr,
  double shift, double scale, 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->GetNumberOfScalarComponents();
  double range[2];
  data->GetPointData()->GetScalars()->GetDataTypeRange(range);

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

  // reformat data into unsigned char

  T* inPtr = dataPtr;
  T* inPtr1 = inPtr;

  int i;
  int j = height;

  unsigned char* newPtr;
  if (bpp < 4)
  {
    newPtr = new unsigned char[vtkPadToFour(3 * width * height)];
  }
  else
  {
    newPtr = new unsigned char[4 * width * height];
  }

  unsigned char* ptr = newPtr;
  double val;
  unsigned char tmp;

  while (--j >= 0)
  {
    inPtr = inPtr1;
    i = width;
    switch (bpp)
    {
      case 1:
        while (--i >= 0)
        {
          vtkClampToUnsignedChar(tmp, ((*inPtr++ + shift) * scale));
          *ptr++ = tmp;
          *ptr++ = tmp;