Method GPURender

Rendering/VolumeOpenGL2/vtkOpenGLGPUVolumeRayCastMapper.cxx:3184–3319

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//------------------------------------------------------------------------------
void vtkOpenGLGPUVolumeRayCastMapper::GPURender(vtkRenderer* ren, vtkVolume* vol)
{
  vtkOpenGLClearErrorMacro();

  const bool isInteractive = vol->GetAllocatedRenderTime() < 1.0;
  const auto previousVolumetricScatteringBlending = this->VolumetricScatteringBlending;
  if (isInteractive)
  {
    // Turn off volumetric multi-scattering for interactive renders
    this->VolumetricScatteringBlending = 0;
  }

  vtkOpenGLCamera* cam = vtkOpenGLCamera::SafeDownCast(ren->GetActiveCamera());

  if (this->GetBlendMode() == vtkVolumeMapper::ISOSURFACE_BLEND &&
    vol->GetProperty()->GetIsoSurfaceValues()->GetNumberOfContours() == 0)
  {
    // Early exit: nothing to render.
    return;
  }

  vtkOpenGLRenderWindow* renWin = vtkOpenGLRenderWindow::SafeDownCast(ren->GetRenderWindow());
  this->ResourceCallback->RegisterGraphicsResources(renWin);
  // Make sure the context is current
  renWin->MakeCurrent();

  // Get window size and corners
  this->Impl->CheckPropertyKeys(vol);
  if (!this->Impl->PreserveViewport)
  {
    ren->GetTiledSizeAndOrigin(this->Impl->WindowSize, this->Impl->WindowSize + 1,
      this->Impl->WindowLowerLeft, this->Impl->WindowLowerLeft + 1);
  }
  else
  {
    int vp[4];
    glGetIntegerv(GL_VIEWPORT, vp);
    this->Impl->WindowLowerLeft[0] = vp[0];
    this->Impl->WindowLowerLeft[1] = vp[1];
    this->Impl->WindowSize[0] = vp[2];
    this->Impl->WindowSize[1] = vp[3];
  }

  this->Impl->NeedToInitializeResources =
    (this->Impl->ReleaseResourcesTime.GetMTime() > this->Impl->InitializationTime.GetMTime());

  this->ComputeReductionFactor(vol->GetAllocatedRenderTime());
  if (!this->Impl->SharedDepthTextureObject)
  {
    this->Impl->CaptureDepthTexture(ren);
  }

  vtkMTimeType renderPassTime = this->GetRenderPassStageMTime(vol);

  const auto multiVol = vtkMultiVolume::SafeDownCast(vol);
  this->Impl->MultiVolume = multiVol && this->GetInputCount() > 1 ? multiVol : nullptr;

  this->Impl->ClearRemovedInputs(renWin);