glsl: Add a lowering pass for gl_VertexID
Converts gl_VertexID to (gl_VertexIDMESA + gl_BaseVertex). gl_VertexIDMESA
is backed by SYSTEM_VALUE_VERTEX_ID_ZERO_BASE, and gl_BaseVertex is backed
by SYSTEM_VALUE_BASE_VERTEX.
v2: Put the enum in struct gl_constants and propoerly resolve the scope
in C++ code. Fix suggested by Marek.
v3: Reabase on Matt's foreach_in_list changes (was using foreach_list).
v4 (Ken): Use a systemvalue instead of a uniform because
STATE_BASE_VERTEX has been removed.
v5: Use a boolean to select lowering, and only allow one lowering
method. Suggested by Ken.
v6 (Ken): Replace strcmp against literal "gl_BaseVertex"/"gl_VertexID"
with SYSTEM_VALUE enum checks, for efficiency.
v7: Rebase on context constant initialization work.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index bdd81c7..97d29e2 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1737,6 +1737,9 @@
}
}
+ if (ctx->Const.VertexID_is_zero_based)
+ lower_vertex_id(linked);
+
/* Make a pass over all variable declarations to ensure that arrays with
* unspecified sizes have a size specified. The size is inferred from the
* max_array_access field.