On 6/16/2012 5:43 PM, Marcin Slusarz wrote:
gl_ClipDistance needs special treatment in form of lowering pass which transforms gl_ClipDistance representation from float[] to vec4[]. There are 2 implementations - at glsl linker level (enabled by LowerClipDistance option) and at glsl_to_tgsi level (enabled unconditionally for gallium drivers). Second implementation is incomplete - it does not take into account transform feedback (see commit 642e5b413e0890b2070ba78fde42db381eaf02e5 "mesa: Fix transform feedback of unsubscripted gl_ClipDistance array" for details).There are 2 possible fixes: - adding transform feedback support into glsl_to_tgsi version - ripping gl_ClipDistance support from glsl_to_tgsi and enabling gl_ClipDistance lowering on glsl linker side This patch implements 2nd option. All it does is: - reverts most of the commit 59be691638200797583bce39a83f641d30d97492 "st/mesa: add support for gl_ClipDistance" - changes LowerClipDistance to true Fixes Piglit tests "EXT_transform_feedback/builtin-varyings gl_ClipDistance[{2,3,4,5,6,7,8}]-no-subscript" on nv50. ---
I can't say I know much about how transform feedback works, but is there a reason that the first fix would be difficult? It seems like a waste to not take advantage of hardware support for clip distances because the current implementation isn't complete.
-Bryan _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
