Method GetZbufferData

Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx:2515–2644

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int vtkOpenGLRenderWindow::GetZbufferData(int x1, int y1, int x2, int y2, float* z_data)
{
  int y_low;
  int x_low;
  int width, height;

  // set the current window
  this->MakeCurrent();

  if (y1 < y2)
  {
    y_low = y1;
  }
  else
  {
    y_low = y2;
  }

  if (x1 < x2)
  {
    x_low = x1;
  }
  else
  {
    x_low = x2;
  }

  width = abs(x2 - x1) + 1;
  height = abs(y2 - y1) + 1;

  // Error checking
  // Must clear previous errors first.
  while (glGetError() != GL_NO_ERROR)
  {
  }

  this->GetState()->vtkglDisable(GL_SCISSOR_TEST);

  // Calling pack alignment ensures that we can grab the any size window
  this->GetState()->vtkglPixelStorei(GL_PACK_ALIGNMENT, 1);

  this->GetState()->PushReadFramebufferBinding();

  this->RenderFramebuffer->Bind(GL_READ_FRAMEBUFFER);
  this->RenderFramebuffer->ActivateReadBuffer(0);

  // Let's determine if we're reading from an FBO.
  bool resolveMSAA = this->GetBufferNeedsResolving();

  if (resolveMSAA)
  {
    this->GetState()->PushDrawFramebufferBinding();
    int* fbsize = this->RenderFramebuffer->GetLastSize();
    this->ResolveFramebuffer->Resize(fbsize[0], fbsize[1]);
    this->ResolveFramebuffer->Bind(GL_DRAW_FRAMEBUFFER);

    // Now blit to resolve the MSAA and get an anti-aliased rendering in
    // resolvedFBO.