gallium: add new semantics for tessellation

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/auxiliary/tgsi/tgsi_strings.c

@@ -90,6 +90,11 @@ const char *tgsi_semantic_names[TGSI_SEMANTIC_COUNT] =
    "INVOCATIONID",
    "VERTEXID_NOBASE",
    "BASEVERTEX",
+   "PATCH",
+   "TESSCOORD",
+   "TESSOUTER",
+   "TESSINNER",
+   "VERTICESIN",
 };
 
 const char *tgsi_texture_names[TGSI_TEXTURE_COUNT] =

src/gallium/docs/source/tgsi.rst

@@ -2894,6 +2894,43 @@ and only the X component is used.
 FIXME: This right now can be either a ordinary input or a system value...
 
 
+TGSI_SEMANTIC_PATCH
+"""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates a
+generic per-patch attribute. Such semantics will not implicitly be per-vertex
+arrays.
+
+TGSI_SEMANTIC_TESSCOORD
+"""""""""""""""""""""""
+
+For tessellation evaluation shaders, this semantic label indicates the
+coordinates of the vertex being processed. This is available in XYZ; W is
+undefined.
+
+TGSI_SEMANTIC_TESSOUTER
+"""""""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates the
+outer tessellation levels of the patch. Isoline tessellation will only have XY
+defined, triangle will have XYZ and quads will have XYZW defined. This
+corresponds to gl_TessLevelOuter.
+
+TGSI_SEMANTIC_TESSINNER
+"""""""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates the
+inner tessellation levels of the patch. The X value is only defined for
+triangle tessellation, while quads will have XY defined. This is entirely
+undefined for isoline tessellation.
+
+TGSI_SEMANTIC_VERTICESIN
+""""""""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates the
+number of vertices provided in the input patch. Only the X value is defined.
+
+
 Declaration Interpolate
 ^^^^^^^^^^^^^^^^^^^^^^^
 

src/gallium/include/pipe/p_shader_tokens.h

@@ -180,7 +180,12 @@ struct tgsi_declaration_interp
 #define TGSI_SEMANTIC_INVOCATIONID 27
 #define TGSI_SEMANTIC_VERTEXID_NOBASE 28
 #define TGSI_SEMANTIC_BASEVERTEX 29
-#define TGSI_SEMANTIC_COUNT      30 /**< number of semantic values */
+#define TGSI_SEMANTIC_PATCH      30 /**< generic per-patch semantic */
+#define TGSI_SEMANTIC_TESSCOORD  31 /**< coordinate being processed by tess */
+#define TGSI_SEMANTIC_TESSOUTER  32 /**< outer tessellation levels */
+#define TGSI_SEMANTIC_TESSINNER  33 /**< inner tessellation levels */
+#define TGSI_SEMANTIC_VERTICESIN 34 /**< number of input vertices */
+#define TGSI_SEMANTIC_COUNT      35 /**< number of semantic values */
 
 struct tgsi_declaration_semantic
 {