From: Ian Romanick <ian.d.roman...@intel.com>
There exists hardware, such as i965, that does not implement the OpenGL
semantic for gl_VertexID. Instead, that hardware does not include the
value of basevertex in the gl_VertexID value.
SYSTEM_VALUE_VERTEX_ID_ZERO_BASE is the system value that represents
this semantic.
Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
Cc: "10.2" <mesa-sta...@lists.freedesktop.org>
---
src/mesa/main/mtypes.h | 12 ++++++++++++
src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 1 +
2 files changed, 13 insertions(+)
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 34e66c9..91f29a8 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2058,6 +2058,8 @@ typedef enum
*
* gl_VertexID gets basevertex added in. This differs from DirectX where
* it's equivalent to gl_VertexID does \b not get basevertex added in.
+ *
+ * \sa SYSTEM_VALUE_VERTEX_ID_ZERO_BASE
*/
SYSTEM_VALUE_VERTEX_ID,
@@ -2089,6 +2091,16 @@ typedef enum
* Note that baseinstance is \b not included in the value of instance.
*/
SYSTEM_VALUE_INSTANCE_ID,
+
+ /**
+ * DirectX-style vertex ID.
+ *
+ * Unlike \c SYSTEM_VALUE_VERTEX_ID, this system value does \b not include
+ * the value of basevertex.
+ *
+ * \sa SYSTEM_VALUE_VERTEX_ID, SYSTEM_VALUE_BASE_VERTEX
+ */
+ SYSTEM_VALUE_VERTEX_ID_ZERO_BASE,
/*@}*/
/**
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index fa95493..5e4b497 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -4240,6 +4240,7 @@ const unsigned _mesa_sysval_to_semantic[SYSTEM_VALUE_MAX]
= {
*/
TGSI_SEMANTIC_VERTEXID,
TGSI_SEMANTIC_INSTANCEID,
+ 0,
/* Geometry shader
*/
--
1.8.1.4
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