i965: fix alpha test for MRT
Include src0 alpha in the RT write message when using MRT, so it is used
for the alpha test instead of the normal per-RT alpha value.
Fixes broken rendering in Dota2 under Wine [FDO #62647].
No Piglit regressions on Ivybridge.
V2: reuse (and simplify) existing sample_alpha_to_coverage flag in
the FS key, rather than adding another redundant one.
Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewd-by: Paul Berry <stereotype441@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=62647
NOTE: This is a candidate for the stable branches.
diff --git a/src/mesa/drivers/dri/i965/brw_wm.c b/src/mesa/drivers/dri/i965/brw_wm.c
index 6eb4a1d..5f681f6 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -277,8 +277,8 @@
old_key->flat_shade, key->flat_shade);
found |= key_debug(intel, "number of color buffers",
old_key->nr_color_regions, key->nr_color_regions);
- found |= key_debug(intel, "sample alpha to coverage",
- old_key->sample_alpha_to_coverage, key->sample_alpha_to_coverage);
+ found |= key_debug(intel, "MRT alpha test or alpha-to-coverage",
+ old_key->replicate_alpha, key->replicate_alpha);
found |= key_debug(intel, "rendering to FBO",
old_key->render_to_fbo, key->render_to_fbo);
found |= key_debug(intel, "fragment color clamping",
@@ -461,8 +461,10 @@
/* _NEW_BUFFERS */
key->nr_color_regions = ctx->DrawBuffer->_NumColorDrawBuffers;
- /* _NEW_MULTISAMPLE */
- key->sample_alpha_to_coverage = ctx->Multisample.SampleAlphaToCoverage;
+
+ /* _NEW_MULTISAMPLE, _NEW_COLOR, _NEW_BUFFERS */
+ key->replicate_alpha = ctx->DrawBuffer->_NumColorDrawBuffers > 1 &&
+ (ctx->Multisample.SampleAlphaToCoverage || ctx->Color.AlphaEnabled);
/* BRW_NEW_VUE_MAP_GEOM_OUT */
if (intel->gen < 6)