[Mesa-dev] [PATCH] glsl: add support for gl_InstanceID

[Marcin Slusarz]

...by copying support for gl_InstanceIDARB, but without "#extension" check,
because EXT_draw_instanced spec does not say anything about it (as opposed
to ARB_draw_instanced / gl_InstanceIDARB) and NVIDIA driver already allow it
---
I'm not sure this is correct.

With this patch applied (+ merged floating branch) I can run OilRush on nv50
(run == watch the game crash in a few seconds ;)

 src/glsl/ir_variable.cpp |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/src/glsl/ir_variable.cpp b/src/glsl/ir_variable.cpp
index 18a3e0f..bd776ee 100644
--- a/src/glsl/ir_variable.cpp
+++ b/src/glsl/ir_variable.cpp
@@ -34,6 +34,10 @@ static void
 generate_ARB_draw_instanced_variables(exec_list *,
                                       struct _mesa_glsl_parse_state *,
                                       bool, _mesa_glsl_parser_targets);
+static void
+generate_EXT_draw_instanced_variables(exec_list *,
+                                      struct _mesa_glsl_parse_state *,
+                                      bool, _mesa_glsl_parser_targets);
 
 static ir_variable *
 add_variable(const char *name, enum ir_variable_mode mode, int slot,
@@ -335,6 +339,8 @@ initialize_vs_variables(exec_list *instructions,
    if (state->ARB_draw_instanced_enable)
       generate_ARB_draw_instanced_variables(instructions, state, false,
                                             vertex_shader);
+   generate_EXT_draw_instanced_variables(instructions, state, false,
+                                            vertex_shader);
 }
 
 
@@ -454,6 +460,25 @@ generate_ARB_draw_instanced_variables(exec_list *instructions,
    }
 }
 
+static void
+generate_EXT_draw_instanced_variables(exec_list *instructions,
+                                      struct _mesa_glsl_parse_state *state,
+                                      bool warn,
+                                      _mesa_glsl_parser_targets target)
+{
+   /* gl_InstanceID is only available in the vertex shader.
+    */
+   if (target == vertex_shader) {
+      ir_variable *const inst =
+         add_variable("gl_InstanceID", ir_var_system_value,
+                      SYSTEM_VALUE_INSTANCE_ID,
+                      glsl_type::int_type, instructions, state->symbols);
+
+      if (warn)
+         inst->warn_extension = "GL_EXT_draw_instanced";
+   }
+}
+
 
 static void
 generate_ARB_shader_stencil_export_variables(exec_list *instructions,
-- 
1.7.2.2