This patch series cleans up a bug fix I made to Mesa on June 22 (commit 82d2596: i965: Compute dFdy() correctly for FBOs). The bug was that the i965 driver wasn't adjusting the dFdy() logic to account for the fact that window system framebuffers use flipped Y coordinates compared to FBOs. The fix was to compile fragment shaders differently when they are used for FBOs vs window system framebuffers.
Commit 82d2596 conservatively assumed that all fragment shader programs might use dFdy(), so it recompiled all of them when switching between FBOs and window system framebuffers. For shaders that don't use dFdy(), the recompile is an unnecessary performance hit. This patch series adds accounting to core mesa to keep track of whether or not a shader uses dFdy(), and changes the i965 back-end to only recompile shaders that actually need it. Patches 1-3 may be of interest to non-i965 developers, since the accounting in core Mesa applies to all back-ends. [PATCH 1/4] mesa: Add UsesDFdy to struct gl_fragment_program. [PATCH 2/4] mesa: Set UsesDFdy appropriately for assembly programs. [PATCH 3/4] glsl: Set UsesDFdy appropriately for GLSL shaders. [PATCH 4/4] i965: Avoid unnecessary recompiles for shaders that don't use dFdy(). _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
