Method CreateFramebuffers

Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx:2774–2873

------------------------------------------------------------------------------ Description: Create an offScreen window based on OpenGL framebuffer extension. Return if the creation was successful or not. \pre positive_width: width>0 \pre positive_height: height>0 \post valid_result: (result==0 || result==1)

// \pre positive_height: height>0
// \post valid_result: (result==0 || result==1)
int vtkOpenGLRenderWindow::CreateFramebuffers(int width, int height)
{
  assert("pre: positive_width" && width > 0);
  assert("pre: positive_height" && height > 0);

#if defined(__APPLE__)
  // make sure requested multisamples is OK with platform
  // APPLE Intel systems seem to have buggy multisampled
  // framebuffer blits etc that cause issues
  if (this->MultiSamples > 0)
  {
    if (this->GetState()->GetVendor().find("Intel") != std::string::npos)
    {
      this->MultiSamples = 0;
    }
  }
#endif

  if (this->LastMultiSamples != this->MultiSamples)
  {
    this->RenderFramebuffer->ReleaseGraphicsResources(this);
  }

  if (!this->RenderFramebuffer->GetFBOIndex())
  {
    // verify that our multisample setting does not exceed the hardware
    if (this->MultiSamples)
    {
#ifdef GL_MAX_SAMPLES
      int msamples = 0;
      this->GetState()->vtkglGetIntegerv(GL_MAX_SAMPLES, &msamples);
      this->MultiSamples = std::min(this->MultiSamples, msamples);
      if (this->MultiSamples == 1)
      {
        this->MultiSamples = 0;
      }
#else
      this->MultiSamples = 0;
#endif
    }
    this->GetState()->PushFramebufferBindings();
    this->RenderFramebuffer->PopulateFramebuffer(width, height,
#ifdef GL_TEXTURE_2D_MULTISAMPLE
      true, // textures
#else
      this->MultiSamples ? false : true, // textures
#endif
      1, VTK_UNSIGNED_CHAR,                    // 1 color buffer uchar
      true, this->RenderBufferTargetDepthSize, // depth buffer
      this->MultiSamples, this->StencilCapable != 0);
    this->LastMultiSamples = this->MultiSamples;
    this->GetState()->PopFramebufferBindings();
  }
  else
  {
    this->RenderFramebuffer->Resize(width, height);
  }