Method LoadTexture

Rendering/VolumeOpenGL2/vtkVolumeTexture.cxx:296–581

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
bool vtkVolumeTexture::LoadTexture(int interpolation, VolumeBlock* volBlock)
{
  int const noOfComponents = this->Scalars->GetNumberOfComponents();
  int scalarType = this->Scalars->GetDataType();

  auto dataSet = volBlock->DataSet;
  auto imBlock = vtkImageData::SafeDownCast(dataSet);
  auto rgBlock = vtkRectilinearGrid::SafeDownCast(dataSet);
  int blockExt[6];
  if (imBlock)
  {
    imBlock->GetExtent(blockExt);
  }
  else if (rgBlock)
  {
    rgBlock->GetExtent(blockExt);
  }
  Size3 const& blockSize = volBlock->TextureSize;
  vtkTextureObject* texture = volBlock->TextureObject;
  vtkIdType const& tupleIdx = volBlock->TupleIndex;

  auto ostate = texture->GetContext()->GetState();

  bool success = true;
  if (!this->HandleLargeDataTypes)
  {
    // Adjust strides used by OpenGL to load the data (X and Y strides in case the
    // texture had to be split on those axis).
    bool const useXStride = blockSize[0] != this->FullSize[0];
    if (useXStride)
    {
      ostate->vtkglPixelStorei(GL_UNPACK_ROW_LENGTH, this->FullSize[0]);
    }

    bool const useYStride = blockSize[1] != this->FullSize[1];
    if (useYStride)
    {
      ostate->vtkglPixelStorei(GL_UNPACK_IMAGE_HEIGHT, this->FullSize[1]);
    }

    // Account for component offset
    // index = ( z0 * Dx * Dy + y0 * Dx + x0 ) * numComp
    vtkIdType const dataIdx = tupleIdx * noOfComponents;
    void* dataPtr = this->Scalars->GetVoidPointer(dataIdx);

    if (this->StreamBlocks)
    {
      success = texture->Create3DFromRaw(
        blockSize[0], blockSize[1], blockSize[2], noOfComponents, scalarType, dataPtr);
    }
    else
    {
      success = SafeLoadTexture(
        texture, blockSize[0], blockSize[1], blockSize[2], noOfComponents, scalarType, dataPtr);
    }
    texture->Activate();
    texture->SetWrapS(vtkTextureObject::ClampToEdge);
    texture->SetWrapT(vtkTextureObject::ClampToEdge);