Method GetNoiseTextureUnit

Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx:3036–3082

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//------------------------------------------------------------------------------
int vtkOpenGLRenderWindow::GetNoiseTextureUnit()
{
  if (!this->NoiseTextureObject)
  {
    this->NoiseTextureObject = vtkTextureObject::New();
    this->NoiseTextureObject->SetContext(this);
  }

  if (this->NoiseTextureObject->GetHandle() == 0)
  {
    vtkNew<vtkJPEGReader> imgReader;

    vtkNew<vtkMemoryResourceStream> stream;
    stream->SetBuffer(BlueNoiseTexture64x64, sizeof(BlueNoiseTexture64x64));
    imgReader->SetStream(stream);
    imgReader->Update();
    vtkImageData* textureReader = imgReader->GetOutput();

    constexpr int bufferSize = 64 * 64;
    float* noiseTextureData = new float[bufferSize];
    for (int i = 0; i < bufferSize; i++)
    {
      int const x = i % 64;
      int const y = i / 64;
      noiseTextureData[i] = textureReader->GetScalarComponentAsFloat(x, y, 0, 0) / 255.0f;
    }

    // Prepare texture
    this->NoiseTextureObject->Create2DFromRaw(64, 64, 1, VTK_FLOAT, noiseTextureData);

    this->NoiseTextureObject->SetWrapS(vtkTextureObject::Repeat);
    this->NoiseTextureObject->SetWrapT(vtkTextureObject::Repeat);
    this->NoiseTextureObject->SetMagnificationFilter(vtkTextureObject::Nearest);
    this->NoiseTextureObject->SetMinificationFilter(vtkTextureObject::Nearest);
    delete[] noiseTextureData;
  }

  int result = this->GetTextureUnitForTexture(this->NoiseTextureObject);

  if (result >= 0)
  {
    return result;
  }

  this->NoiseTextureObject->Activate();
  return this->GetTextureUnitForTexture(this->NoiseTextureObject);
}

//------------------------------------------------------------------------------
void vtkOpenGLRenderWindow::Render()