658921 - OpenGL layers disables acceleration of HWACCEL benchmark with Mesa

Status: RESOLVED DUPLICATE of bug 670645

(Core :: Graphics, defect)

Description

[Karl Tomlinson (:karlt)]

+++ This bug was initially created as a clone of Bug #606855 +++

With tinderbox build http://hg.mozilla.org/mozilla-central/rev/f9a070327df8
(which includes the fix for bug 606855),
the benchmark, http://demos.hacks.mozilla.org/openweb/HWACCEL/
gives me 60 FPS without "Use hardware acceleration when available" checked but only 10 or 11 FPS with that checked.

OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: Mesa DRI R600 (JUNIPER 68A0) 20090101  TCL DRI2
OpenGL version string: 2.1 Mesa 7.10.2

[Thursday 28 October 2010] [09:00:15] <karlt>   doesn't mesa have a 4096 pixel limit on textures or something?
[Thursday 28 October 2010] [09:00:50] <ajax>    yes.

[Thursday 28 October 2010] [09:01:33] <ajax>    the software rasterisation algorithm is in fixed-point math so you have to trade off between rendering quality and texture/triangle size

The RENDER implementation has different (hardware dependent) limits.

Comment 1

[Matt Woodrow (:mattwoodrow)]

Can you check if you're getting texture_from_pixmap support enabled? 

Checking for the 'GLX_EXT_texture_from_pixmap' extension would be useful, as would stepping through the code in GLXLibrary::EnsureInitialized().

Bug 671259 is going to disable GL layers when we don't have support for this, as reading surfaces back from X into system memory is a huge performance regression.

Comment 2

[Karl Tomlinson (:karlt)]

Attachment: use glxGetProcAddress to find glxBindTexImageEXT

glXBindTexImageEXT and glXReleaseTexImageEXT are not present as exported symbols in Mesa's libGL.so.1, so glxGetProcAddress needs to be used to find them.

This increases FPS in my debug build from 7 to 47 FPS, still not as high as with RENDER, but this does suggest that the compositing is now happening in hardware.
(A debug build is probably not really appropriate for such comparisons with RENDER.)

Comment 3

[Matt Woodrow (:mattwoodrow)]

Thanks Karl, this sounds like a dupe of bug 670645. This change should be on trunk already :)