Kenneth Graunke
7183568869
This optimization attempts to avoid extra attribute interpolation
instructions for texture coordinates where the W-component is 1.0.
Unfortunately, it requires a lot of complexity: the brw_wm_input_sizes
state atom (all the brw_vs_constval.c code) needs to run on each draw.
It computes the input_size_masks array, then uses that to compute
proj_attrib_mask. Differences in proj_attrib_mask can cause
state-dependent fragment shader recompiles. We also often fail to guess
proj_attrib_mask for the fragment shader precompile, causing us to
needlessly compile it twice.
Furthermore, this optimization only applies to fixed-function programs;
it does not help modern GLSL-based programs at all. Generally, older
fixed-function programs run fine on modern hardware anyway.
The optimization has existed in some form since the initial commit. When
we rewrote the fragment shader backend, we dropped it for a while. Eric
readded it in commit eb30820f26 as part of
an attempt to cure a ~1% performance regression caused by converting the
fixed-function fragment shader generation code from Mesa IR to GLSL IR.
However, no performance data was included in the commit message, so it's
unclear whether or not it was successful.
Time has passed, so I decided to re-measure this. Surprisingly,
Eric's OpenArena timedemo actually runs /faster/ after removing this and
the brw_wm_input_sizes atom. On Ivybridge at 1024x768, I measured a
1.39532% +/- 0.91833% increase in FPS (n = 55). On Ironlake, there was
no statistically significant difference (n = 37).
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
File: docs/README.WIN32 Last updated: 23 April 2011 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons osmesa mesagdi to build classic mesa Windows GDI drivers; or scons libgl-gdi to build gallium based GDI driver. This will work both with MSVS or Mingw. Windows Drivers ------- ------- At this time, only the gallium GDI driver is known to work. Source code also exists in the tree for other drivers in src/mesa/drivers/windows, but the status of this code is unknown. General ------- After building, you can copy the above DLL files to a place in your PATH such as $SystemRoot/SYSTEM32. If you don't like putting things in a system directory, place them in the same directory as the executable(s). Be careful about accidentially overwriting files of the same name in the SYSTEM32 directory. The DLL files are built so that the external entry points use the stdcall calling convention. Static LIB files are not built. The LIB files that are built with are the linker import files associated with the DLL files. The si-glu sources are used to build the GLU libs. This was done mainly to get the better tessellator code. If you have a Windows-related build problem or question, please post to the mesa-dev or mesa-users list.