Mesa (master): tgsi: clarify TGSI_SEMANTIC_SAMPLEMASK documentation

[Brian Paul]

Module: Mesa
Branch: master
Commit: 81e15a5dea2e50135a83d249944e12537f6b152e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=81e15a5dea2e50135a83d249944e12537f6b152e

Author: Brian Paul <brianp at vmware.com>
Date:   Fri Jun  9 07:45:02 2017 -0600

tgsi: clarify TGSI_SEMANTIC_SAMPLEMASK documentation

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

---

 src/gallium/docs/source/tgsi.rst | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index eceaa6d64f..7fb963fde5 100644
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -3298,8 +3298,9 @@ TGSI_SEMANTIC_SAMPLEMASK
 """"""""""""""""""""""""
 
 For fragment shaders, this semantic label indicates that an output contains
-the sample mask used to disable further sample processing
-(i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
+the sample mask used to disable further sample processing.  The output's
+type is uint[4] but only the X component is used (i.e. gl_SampleMask[0]).
+Each bit corresponds to one sample position (up to 32x MSAA is supported).
 
 TGSI_SEMANTIC_INVOCATIONID
 """"""""""""""""""""""""""