Mesa (master): tgsi: clarify TGSI_SEMANTIC_{LAYER,VIEWPORT_INDEX}

[Nicolai Hähnle]

Module: Mesa
Branch: master
Commit: f3d2cf6c1ff6ccf16c2a471f8f05c4ed5a734ae4
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f3d2cf6c1ff6ccf16c2a471f8f05c4ed5a734ae4

Author: Nicolai Hähnle <nicolai.haehnle at amd.com>
Date:   Thu Apr 13 22:13:55 2017 +0200

tgsi: clarify TGSI_SEMANTIC_{LAYER,VIEWPORT_INDEX}

Depending on pipe caps they can be writable in all vertex processing
stages, but only the output of the last stage counts.

Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Reviewed-by: Edward O'Callaghan <funfunctor at folklore1984.net>

---

 src/gallium/docs/source/tgsi.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index 89acb521ce..e740476ff0 100644
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -3212,6 +3212,11 @@ For geometry shaders, this semantic label indicates that an output
 contains the index of the viewport (and scissor) to use.
 This is an integer value, and only the X component is used.
 
+If PIPE_CAP_TGSI_VS_LAYER_VIEWPORT or PIPE_CAP_TGSI_TES_LAYER_VIEWPORT is
+supported, then this semantic label can also be used in vertex or
+tessellation evaluation shaders, respectively. Only the value written in the
+last vertex processing stage is used.
+
 
 TGSI_SEMANTIC_LAYER
 """""""""""""""""""
@@ -3221,6 +3226,11 @@ contains the layer value to use for the color and depth/stencil surfaces.
 This is an integer value, and only the X component is used.
 (Also known as rendertarget array index.)
 
+If PIPE_CAP_TGSI_VS_LAYER_VIEWPORT or PIPE_CAP_TGSI_TES_LAYER_VIEWPORT is
+supported, then this semantic label can also be used in vertex or
+tessellation evaluation shaders, respectively. Only the value written in the
+last vertex processing stage is used.
+
 
 TGSI_SEMANTIC_CULLDIST
 """"""""""""""""""""""