[Bf-committers] Back Buffer Issues

[Matthew H. Plough]

Hi all!!

I was playing around with my video card's OpenGL settings this morning, 
and found an interesting clue on what's causing the odd corruption shown 
in http://www.princeton.edu/~mplough/tmp/buttons_error.png . 

First things first: I have a 3Dlabs Wildcat Realizm 200.

Second things second ;) : Like most cards, my card has two options for 
dealing with double buffering -- page flipping (which only exchanges the 
front and back buffer pointers) and Force Swap Copy (which maintains a 
dedicated back buffer and a dedicated display buffer).  When a buffer 
swap happens in forced mode, data from the back buffer is *copied* into 
the display buffer, but is not cleared.  My best interpretation of 
Blender's code leads me to believe that it depends on this preservation 
of back buffer data. 

Is this in fact the case?  If so, how can we fix this?

Matt