On Wed, Aug 22, 2012 at 12:48 AM, Vadim Girlin <vadimgir...@gmail.com> wrote: > Hi, > > It seems there is a problem with alpha-to-coverage-dual-src-blend test. > > AFAICS the test uses DrawPixels with dual source blending and > fixed-function fragment pipeline. According to GL and > ARB_blend_func_extended specs: > > "Rendering using any of the blend functions that consume the second > input color (SRC1_COLOR, ONE_MINUS_SRC1_COLOR, SRC1_ALPHA or > ONE_MINUS_SRC1_ALPHA) using fixed function will produce undefined > results." > > So it looks like the test relies on the undefined behaviour. Here is the > part of the stack for that DrawPixels call: > > 12 visualize_image() common.cpp:1775 > 11 draw_image_to_window_system_fb() draw-buffers-common.cpp:704 > 10 draw_reference_image() draw-buffers-common.cpp:823 > 9 piglit_display() alpha-to-coverage-dual-src-blend.cpp:104 > > Probably blending should be temporarily disabled in that case. Yes. Blending can be temporarily disabled in visualize_image function. I'll send out a small patch to fix this. Patch won't make any difference to the test output. Test is already passing on AMD, Intel and NVIDIA drivers. Thanks for noticing this.
> > Vadim > _______________________________________________ Piglit mailing list Piglit@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/piglit