diff options
| author | Paul Berry <[email protected]> | 2012-06-22 20:27:18 -0700 |
|---|---|---|
| committer | Paul Berry <[email protected]> | 2012-06-26 07:45:54 -0700 |
| commit | bc53e14d98de11593788d302c0bb198e3a2097a4 (patch) | |
| tree | 026c5011395bc36423ca206fbd8619910eb95949 /src/mesa/drivers | |
| parent | 9ea60ce58f8494e0b79771f93227f4b8181731de (diff) | |
i965/msaa: Implement GL_SAMPLE_ALPHA_TO_{COVERAGE,ONE}.
This patch enables the multisampling parameters
GL_SAMPLE_ALPHA_TO_COVERAGE and GL_SAMPLE_ALPHA_TO_ONE, which allow
the fragment shader's alpha output to be converted into a sample
coverage mask and ignored for blending. i965 supports these
parameters through the BLEND_STATE structure.
The GL spec allows, but does not require, the implementation to dither
the conversion from alpha to a sample coverage mask, so that alpha
values that aren't a multiple of 1/num_samples result in the correct
proportion of samples being lit. A bit exists in the BLEND_STATE
structure to enable this functionality, but according to the hardware
docs it must be disabled on Sandy Bridge (see the Sandy Bridge PRM,
Vol2, Part1, p379: AlphaToCoverage Dither Enable). So it is enabled
for Gen7 only.
Fixes piglit tests
"EXT_framebuffer_multisample/sample-alpha-to-{coverage,one} {2,4}".
Reviewed-by: Anuj Phogat <[email protected]>
Diffstat (limited to 'src/mesa/drivers')
| -rw-r--r-- | src/mesa/drivers/dri/i965/gen6_cc.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/mesa/drivers/dri/i965/gen6_cc.c b/src/mesa/drivers/dri/i965/gen6_cc.c index b4c5329772f..e0523efdc70 100644 --- a/src/mesa/drivers/dri/i965/gen6_cc.c +++ b/src/mesa/drivers/dri/i965/gen6_cc.c @@ -161,6 +161,13 @@ gen6_upload_blend_state(struct brw_context *brw) blend[b].blend1.write_disable_g = !ctx->Color.ColorMask[b][1]; blend[b].blend1.write_disable_b = !ctx->Color.ColorMask[b][2]; blend[b].blend1.write_disable_a = !ctx->Color.ColorMask[b][3]; + + /* _NEW_MULTISAMPLE */ + blend[b].blend1.alpha_to_coverage = + ctx->Multisample._Enabled && ctx->Multisample.SampleAlphaToCoverage; + blend[b].blend1.alpha_to_one = + ctx->Multisample._Enabled && ctx->Multisample.SampleAlphaToOne; + blend[b].blend1.alpha_to_coverage_dither = (brw->intel.gen >= 7); } brw->state.dirty.cache |= CACHE_NEW_BLEND_STATE; @@ -169,7 +176,8 @@ gen6_upload_blend_state(struct brw_context *brw) const struct brw_tracked_state gen6_blend_state = { .dirty = { .mesa = (_NEW_COLOR | - _NEW_BUFFERS), + _NEW_BUFFERS | + _NEW_MULTISAMPLE), .brw = BRW_NEW_BATCH, .cache = 0, }, |