glsl: Make gl_InstanceID available with GL_ARB_draw_instanced extension

Originally ARB_draw_instanced only specified that ARB decorated name.
Since no vendor actually implemented that behavior and some apps use
the undecorated name, the extension now specifies that both names are
available.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Marek Olšák <maraeo@gmail.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/src/glsl/builtin_variables.cpp b/src/glsl/builtin_variables.cpp
index ed6b922ca62..66b3abdd84c 100644
--- a/src/glsl/builtin_variables.cpp
+++ b/src/glsl/builtin_variables.cpp
@@ -870,13 +870,25 @@ generate_ARB_draw_instanced_variables(exec_list *instructions,
    /* gl_InstanceIDARB is only available in the vertex shader.
     */
    if (target == vertex_shader) {
-      ir_variable *const inst =
+      ir_variable *inst =
          add_variable(instructions, state->symbols,
 		      "gl_InstanceIDARB", glsl_type::int_type,
 		      ir_var_system_value, SYSTEM_VALUE_INSTANCE_ID);
 
       if (warn)
          inst->warn_extension = "GL_ARB_draw_instanced";
+
+      /* Originally ARB_draw_instanced only specified that ARB decorated name.
+       * Since no vendor actually implemented that behavior and some apps use
+       * the undecorated name, the extension now specifies that both names are
+       * available.
+       */
+      inst = add_variable(instructions, state->symbols,
+			  "gl_InstanceID", glsl_type::int_type,
+			  ir_var_system_value, SYSTEM_VALUE_INSTANCE_ID);
+
+      if (warn)
+         inst->warn_extension = "GL_ARB_draw_instanced";
    }
 }