glsl: Allow varying structs in GLSL ES 3.00 and GLSL 1.50.

Previously I thought that varying structs had been added to GLSL ES
3.00 by mistake, because chapter 11 of the GLSL ES 3.00 spec
("Counting of Inputs and Outputs") failed to mention how structs
should be handled.  Khronos has clarified
(https://cvs.khronos.org/bugzilla/show_bug.cgi?id=9828) that varying
structs are indeed required, and that chapter 11 will be modified to
indicate that the minimal reference packing algorithm flattens varying
structs to their individual components.

Mesa doesn't flatten varying structs to their individual components,
but this is ok, since it packs varyings of all kinds with no wasted
space at all (except where this is impossible due to differing
interpolation modes), so it will outperform the minimal reference
packing algorithm in all but the most pathological cases.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 3c2ce15389a1f44bd13a7173dde0e1561ab93e0c..33e20a8208d2557fcfabe6b2868137b50c33e273 100644 (file)
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -2031,10 +2031,8 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
        * Similar text exists in the section on vertex shader outputs.
        *
        * Similar text exists in the GLSL ES 3.00 spec, except that the GLSL ES
-       * 3.00 spec claims to allow structs as well.  However, this is likely
-       * an error, since section 11 of the spec ("Counting of Inputs and
-       * Outputs") enumerates all possible types of interstage linkage
-       * variables, and it does not mention structs.
+       * 3.00 spec allows structs as well.  Varying structs are also allowed
+       * in GLSL 1.50.
        */
       switch (var->type->get_scalar_type()->base_type) {
       case GLSL_TYPE_FLOAT:
@@ -2049,6 +2047,8 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
                           state->get_version_string());
          break;
       case GLSL_TYPE_STRUCT:
+         if (state->is_version(150, 300))
+            break;
          _mesa_glsl_error(loc, state,
                           "varying variables may not be of type struct");
          break;