[Bug 22045] Re: Poor performance / flickering with OpenGL hacks

[Paul Sladen]

On this machine (i915 graphics) the OpenGL hacks aren't getting a z-buffer (depth buffer) so look like the polygons are all drawn in the wrong order.

I'm guessing the hacks are choosing (or being given...) the wrong GLX visual to draw to.  Eg. if it was choosig the first one in the list, rather than the closest then this would explain it, as:

  $ glxinfo | grep -m1 -B3 '^0x'
     visual  x  bf lv rg d st colorbuffer ax dp st accumbuffer  ms  cav
   id dep cl sp sz l  ci b ro  r  g  b  a bf th cl  r  g  b  a ns b eat
  ----------------------------------------------------------------------
  0x23 24 tc  0 32  0 r  y  .  8  8  8  8  0  0  0  0  0  0  0  0 0 None

the first one is one without an offered double-buffer.
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Poor performance / flickering with OpenGL hacks
https://launchpad.net/malone/bugs/22045