[Mesa-dev] [PATCH] glsl: set user defined varyings to smooth by default in ES

[Timothy Arceri]

This is usually handled by the backends in order to handle the
various interactions with the gl_*Color built-ins.

The problem is this means linking will fail if one side on the
interface adds the smooth qualifier to the varying and the other
side just uses the default even though they match.

This fixes various deqp tests. The spec is not clear what to for
deskto GL so leave it as is for now.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92743
---
 src/compiler/glsl/ast_to_hir.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp
index b639378..4203cd5 100644
--- a/src/compiler/glsl/ast_to_hir.cpp
+++ b/src/compiler/glsl/ast_to_hir.cpp
@@ -2750,6 +2750,17 @@ interpret_interpolation_qualifier(const struct ast_type_qualifier *qual,
                           "vertex shader inputs or fragment shader outputs",
                           interpolation_string(interpolation));
       }
+   } else if (state->es_shader &&
+              ((mode == ir_var_shader_in &&
+                state->stage != MESA_SHADER_VERTEX) ||
+               (mode == ir_var_shader_out &&
+                state->stage != MESA_SHADER_FRAGMENT))) {
+      /* From Section 4.3.9 (Interpolation) of the GLSL ES spec:
+       *
+       *    " When no interpolation qualifier is present, smooth interpolation
+       *    is used."
+       */
+      interpolation = INTERP_QUALIFIER_SMOOTH;
    }
 
    return interpolation;
-- 
2.5.0