[GRASS-dev] Re: [GRASS GIS] #104: saving display to tiff or ppm garbled when NVIZ is not top window

[GRASS GIS]

#104: saving display to tiff or ppm garbled when NVIZ is not top window
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  Reporter:  dylan    |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect   |      Status:  new                      
  Priority:  minor    |   Milestone:  6.4.0                    
 Component:  default  |     Version:  svn-trunk                
Resolution:           |    Keywords:  NVIZ openGL              
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Comment (by glynn):

 It's not an OpenGL bug, but a limitation. If you render to a window, the
 rendering is clipped to the visible portion (the part that's on-screen and
 not obscured by another window). If you read the rendered image (with
 glReadPixels()), the clipped portions will contain garbage.

 The only reliable way to generate image files using OpenGL is to render to
 an off-screen target such as a pBuffer or GLXPixmap. But those require
 support from the driver, and we haven't had much luck with either approach
 (of course, there might be bugs in the code which creates the pBuffer or
 GLXPixmap).

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Ticket URL: <http://trac.osgeo.org/grass/ticket/104#comment:1>
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