[vtk-developers] calling XMapWindow in offscreen mode

[Joe Miller]

Hi,


I was playing with non-mesa offscreen rendering (ie using x to offscreen render) and I noticed that my window still appeared. I know that the documentation says that offscreen mode may not be supported by all windows; however, I also noticed that XMapWindow is called even in offscreen mode. I was curious if this was necessary? I added a conditional around the call (and a few related lines beneith it) in my local copy of vtk and that seems to fix the problem. I'm not a strong x programmer, so I didn't want to put in an official bug without checking around first.

I've tested it on mac OS X, Solaris 10 and Red Hat 5 machines. I'm using vtk 5.4.2. The file affected is vtkXOpenGLRenderWindow.cxx, revision 1.102

I added the conditional at line 641 which encompasses lines 642-654

    if(!this->OffScreenRendering)
      {
      XMapWindow(this->DisplayId, this->WindowId);
      XSync(this->DisplayId,False);
      XGetWindowAttributes(this->DisplayId,
                         this->WindowId,&winattr);
      // guarantee that the window is mapped before the program continues
      // on to do the OpenGL rendering.
      while (winattr.map_state == IsUnmapped)
        {
        XGetWindowAttributes(this->DisplayId,
                           this->WindowId,&winattr);
        }
      }

I appreciate the feedback. 

Thanks

-joe