https://bugs.freedesktop.org/show_bug.cgi?id=27887
--- Comment #1 from Wiktor Janas wixorpeek@gmail.com 2010-05-04 08:22:25 PDT --- Created an attachment (id=35412) View: https://bugs.freedesktop.org/attachment.cgi?id=35412 Review: https://bugs.freedesktop.org/review?bug=27887&attachment=35412
proposed patch
Looks to me like bug in u_blitter.c
The fragment shaders used by clear are generated on demand and cached. However, shader that would pass the input color to the output buffer 0 is stored at the same location as shader that would write to no output buffers (see logic at blitter_get_fs_col). Therefore, if depth-buffer-only clear is done first, subsequent color-buffer clear uses shader that generates no output.
The attached patch attempts to fix this (warning: I don't know mesa/gallium well, just trying to get my app working). The test case still has issues (sometimes fails to redraw the window when resized), but at least something shows up. Also, the same test case renders garbage on llvmpipe (patched or not).