Code review comment for lp:~kiithsacmp/stellarium/glexperiment

Ferdinand Majerech (kiithsacmp) wrote :

I've finally tested it on Catalyst - shadows work fine.
The last thing that needs testing is Mac compilation.

So right now I have it tested on:

AMD open source
AMD Catalyst
NVidia Nouveau
Intel open source

All of them work fine.
Intel open source is about same speed as AMD open source, even though on a much crappier GPU.
Nouveau is about 50% of that (30-35FPS zoomed out no atmosphere/ground)
Catalyst is way faster (120-140FPS, the bottleneck here is most likely CPU)

Catalyst became laggy on very close zoom to a planet with GL2 - but that was on 2560x1440 -
most likely shadow fragment shader overhead

Sorry, did no precise measurements. I'd be more interested in measurements
on stuff that is almost too slow so I can improve performance there
(i.e. improving 80 FPS to 120 is not as good as 20 FPS to 30)

Also; one possible source of slowdown on your Mac (but again, not that huge slowdown):
Viewport effects (i.e. spherical mirror distortion) now work even if FBOs are not used,
(previously they would simply be disabled), but with a round-about, slow implementation.

I also disabled FBO for now because there seems to be a bug in GL2 Qt paint engine,
where the paint engine expects certain state to be set to certain values and I wasn't
able to work around that.

So if you have spherical mirror distortion enabled, you're using the fallback
viewport texture implementation instead of FBOs, which is slow. But again,
not 75-to-15 slow, so I'm not sure.

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