2 files changed, 55 insertions, 5 deletions
diff --git a/src/gallium/docs/source/screen.rst b/src/gallium/docs/source/screen.rst
index e711ad40bef..55d114c829f 100644
--- a/src/gallium/docs/source/screen.rst
+++ b/src/gallium/docs/source/screen.rst
@@ -233,6 +233,14 @@ The integer capabilities:
 * ``PIPE_CAP_CLIP_HALFZ``: Whether the driver supports the
   pipe_rasterizer_state::clip_halfz being set to true. This is required
   for enabling ARB_clip_control.
+* ``PIPE_CAP_VERTEXID_NOBASE``: If true, the driver only supports
+  TGSI_SEMANTIC_VERTEXID_NOBASE (and not TGSI_SEMANTIC_VERTEXID). This means
+  state trackers for APIs whose vertexIDs are offset by basevertex (such as GL)
+  will need to lower TGSI_SEMANTIC_VERTEXID to TGSI_SEMANTIC_VERTEXID_NOBASE
+  and TGSI_SEMANTIC_BASEVERTEX, so drivers setting this must handle both these
+  semantics. Only relevant if geometry shaders are supported.
+  (Currently not possible to query availability of these two semantics outside
+  this, at least BASEVERTEX should be exposed separately too).
 
 
 .. _pipe_capf:
diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index cbb8f74ab89..ff322e864ec 100644
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -2651,7 +2651,7 @@ TGSI_SEMANTIC_VIEWPORT_INDEX
 
 For geometry shaders, this semantic label indicates that an output
 contains the index of the viewport (and scissor) to use.
-Only the X value is used.
+This is an integer value, and only the X component is used.
 
 
 TGSI_SEMANTIC_LAYER
@@ -2659,7 +2659,8 @@ 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.
-Only the X value is used. (Also known as rendertarget array index.)
+This is an integer value, and only the X component is used.
+(Also known as rendertarget array index.)
 
 
 TGSI_SEMANTIC_CULLDIST
@@ -2700,7 +2701,8 @@ TGSI_SEMANTIC_SAMPLEID
 """"""""""""""""""""""
 
 For fragment shaders, this semantic label indicates that a system value
-contains the current sample id (i.e. gl_SampleID). Only the X value is used.
+contains the current sample id (i.e. gl_SampleID).
+This is an integer value, and only the X component is used.
 
 TGSI_SEMANTIC_SAMPLEPOS
 """""""""""""""""""""""
@@ -2720,8 +2722,48 @@ TGSI_SEMANTIC_INVOCATIONID
 """"""""""""""""""""""""""
 
 For geometry shaders, this semantic label indicates that a system value
-contains the current invocation id (i.e. gl_InvocationID). Only the X value is
-used.
+contains the current invocation id (i.e. gl_InvocationID).
+This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_INSTANCEID
+""""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the current instance id (i.e. gl_InstanceID). It does not include the base
+instance. This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_VERTEXID
+""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the current vertex id (i.e. gl_VertexID). It does (unlike in d3d10) include the
+base vertex. This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_VERTEXID_NOBASE
+"""""""""""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the current vertex id without including the base vertex (this corresponds to
+d3d10 vertex id, so TGSI_SEMANTIC_VERTEXID_NOBASE + TGSI_SEMANTIC_BASEVERTEX
+== TGSI_SEMANTIC_VERTEXID). This is an integer value, and only the X component
+is used.
+
+TGSI_SEMANTIC_BASEVERTEX
+""""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the base vertex (i.e. gl_BaseVertex). Note that for non-indexed draw calls,
+this contains the first (or start) value instead.
+This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_PRIMID
+""""""""""""""""""""
+
+For geometry and fragment shaders, this semantic label indicates the value
+contains the primitive id (i.e. gl_PrimitiveID). This is an integer value,
+and only the X component is used.
+FIXME: This right now can be either a ordinary input or a system value...
+
 
 Declaration Interpolate
 ^^^^^^^^^^^^^^^^^^^^^^^