Method MakeTextureData

Rendering/Core/vtkImageMapper3D.cxx:758–903

}

unsigned char* vtkImageMapper3D::MakeTextureData(vtkImageProperty* property, vtkImageData* input,
  int extent[6], int& xsize, int& ysize, int& bytesPerPixel, bool& reuseTexture, bool& reuseData)
{
  int xdim, ydim;
  int imageSize[2];
  int textureSize[2];

  // compute image size and texture size from extent
  this->ComputeTextureSize(extent, xdim, ydim, imageSize, textureSize);

  // number of components
  int numComp = input->GetNumberOfScalarComponents();
  int scalarType = input->GetScalarType();
  int textureBytesPerPixel = 4;

  // lookup table and window/level
  double colorWindow = 255.0;
  double colorLevel = 127.5;
  vtkScalarsToColors* lookupTable = nullptr;

  if (property)
  {
    colorWindow = property->GetColorWindow();
    colorLevel = property->GetColorLevel();
    lookupTable = property->GetLookupTable();
  }

  // check if the input is pre-formatted as colors
  int inputIsColors = false;
  if (lookupTable == nullptr && scalarType == VTK_UNSIGNED_CHAR && colorLevel == 127.5 &&
    colorWindow == 255.0)
  {
    inputIsColors = true;
    if (reuseData && numComp < 4)
    {
      textureBytesPerPixel = numComp;
    }
  }

  // reuse texture if texture size has not changed
  if (xsize == textureSize[0] && ysize == textureSize[1] && bytesPerPixel == textureBytesPerPixel &&
    reuseTexture)
  {
    // if texture is reused, only reload the image portion
    xsize = imageSize[0];
    ysize = imageSize[1];
  }
  else
  {
    xsize = textureSize[0];
    ysize = textureSize[1];
    bytesPerPixel = textureBytesPerPixel;
    reuseTexture = false;
  }

  // if the image is already of the desired size and type
  if (xsize == imageSize[0] && ysize == imageSize[1])
  {