[Mesa-dev] [PATCH] glsl: Allow precision qualifiers for sampler types

[Anuj Phogat]

GLSL 1.30 doesn't allow precision qualifiers on sampler types,
but in GLSL ES, sampler types are also allowed. This seems like
an oversight (since the intention of including these in GLSL 1.30
is to allow compatibility with ES shaders).

Currently, Mesa allows "default" precision qualifiers to be set for
sampler types in GLSL (commit d5948f2). This patch makes it follow
GLSL ES rules and also allow declaring sampler variables with a
precision qualifier in GLSL.

This fixes a shader compilation error in Khronos OpenGL conformance
test "depth_texture_mipmap".

Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com
---
 src/glsl/ast_to_hir.cpp | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 192130a..b3d6d8c 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -3131,8 +3131,8 @@ ast_declarator_list::hir(exec_list *instructions,
          state->check_precision_qualifiers_allowed(&loc);
       }
 
-
-      /* Precision qualifiers only apply to floating point and integer types.
+      /* Precision qualifiers apply to floating point, integer and sampler
+       * types.
        *
        * From section 4.5.2 of the GLSL 1.30 spec:
        *    "Any floating point or any integer declaration can have the type
@@ -3144,20 +3144,24 @@ ast_declarator_list::hir(exec_list *instructions,
        *
        * From page 87 of the GLSL ES spec:
        *    "RESOLUTION: Allow sampler types to take a precision qualifier."
+       *
+       * GLSL 1.30 doesn't allow precision qualifiers on sampler types, but
+       * this seems like an oversight (since the intention of including these
+       * in GLSL 1.30 is to allow compatibility with ES shaders). So we allow
+       * int, float, and all sampler types regardless of GLSL version.
        */
       if (this->type->qualifier.precision != ast_precision_none
           && !var->type->is_float()
           && !var->type->is_integer()
           && !var->type->is_record()
-          && !(var->type->is_sampler() && state->es_shader)
+          && !(var->type->is_sampler())
           && !(var->type->is_array()
                && (var->type->fields.array->is_float()
                    || var->type->fields.array->is_integer()))) {
 
          _mesa_glsl_error(&loc, state,
                           "precision qualifiers apply only to floating point"
-                          "%s types", state->es_shader ? ", integer, and sampler"
-						       : "and integer");
+                          ", integer and sampler types");
       }
 
       /* From page 17 (page 23 of the PDF) of the GLSL 1.20 spec:
-- 
1.8.1.4