Comment 6 for bug 901097

On Tue, 20 Mar 2012, Daniel van Vugt wrote:

> Sam, I reviewed the options again last Friday. What I found was:
>
> 1. The GLES branch looks promising and merges cleanly but:
> (a) It's too late to consider a new core rendering algorithm for precise; and
> (b) The diff is still over 11k lines. Yet another reason why it won't land in 0.9.7.
>

I think what I was getting at is that we should look to backporting the
paint-fbo stuff that's in the current linaro branch. That is only about
400 lines, most of which is framebuffer management stuff.

> 2. Forcing full screen redraws (not really a code change, just a config change) now performs better than regional redraws in most cases. Full screen redraws provide higher framerates and equal or _lower_ CPU usage than regional redraws. The only exception was on a very slow system which got its framerate doubled, so the CPU increased somewhat in a good way. The other problem with full screen redraws is that there seems to be high lag when used on multiple monitors. I think someone has logged a bug for that already...
> I personally would not mind forcing full screen redraws right now as it will fix more peoples bugs than it would cause. But I won't do so because we are in freeze and it would still be risky to change core config so late.
>

Forcing fullscreen redraws means that the damage-intersection detection
code will be turned off and we also can't use plugins like showrepaint in debugging. We
can use full screen redraws by default this cycle but it is not a long
term solution.

> 3. Interestingly in the GLES code I saw some hints that they encountered
> the same kind of rendering bugs as I did with my prototype in comment
> #1. This suggests they are indeed plugin bugs.
>
> I think at this late stage in the precise cycle, then only sane solution
> to bug 930192 is not to fix this bug yet, but use one of the quick
> solutions documented there --> bug 930192.
>
> --
> You received this bug notification because you are a member of compiz
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> https://bugs.launchpad.net/bugs/901097
>
> Title:
> Add option to use glXSwapBuffers on every frame, not just full-screen
> redraws.
>
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