[Mesa-dev] [PATCH 2/5] tgsi: clarify TGSI_SEMANTIC_{LAYER, VIEWPORT_INDEX}

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

Depending on pipe caps they can be writable in all vertex processing
stages, but only the output of the last stage counts.
---
 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 f68d349..6ba37aa 100644
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -3203,29 +3203,39 @@ is a writable stencil reference value. Only the Y component is writable.
 This allows the fragment shader to change the fragments stencilref value.
 
 
 TGSI_SEMANTIC_VIEWPORT_INDEX
 """"""""""""""""""""""""""""
 
 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
 """""""""""""""""""
 
 For geometry shaders, this semantic label indicates that an output
 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
 """"""""""""""""""""""
 
 Used as distance to plane for performing application-defined culling
 of individual primitives against a plane. When components of vertex
 elements are given this label, these values are assumed to be a
 float32 signed distance to a plane. Primitives will be completely
 discarded if the plane distance for all of the vertices in the
 primitive are < 0. If a vertex has a cull distance of NaN, that
-- 
2.9.3