glsl: do not emit error for non written varyings on OpenGL ES

Patch fixes following test case from 'shaders-with-varyings' WebGL
conformance suite: "vertex shader with unused varying and fragment
shader with used varying must succeed"

v2: emit still a warning if the condition happens (Ian)

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index a738e2f382583f5b82aa10b035bbdd90239fa30b..1866ab265f23673d91627a3f73ccf638dd39355d 100644 (file)
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -1456,7 +1456,22 @@ assign_varying_locations(struct gl_context *ctx,
 
          if (var && var->data.mode == ir_var_shader_in &&
              var->data.is_unmatched_generic_inout) {
-            if (prog->Version <= 120) {
+            if (prog->IsES) {
+               /*
+                * On Page 91 (Page 97 of the PDF) of the GLSL ES 1.0 spec:
+                *
+                *     If the vertex shader declares but doesn't write to a
+                *     varying and the fragment shader declares and reads it,
+                *     is this an error?
+                *
+                *     RESOLUTION: No.
+                */
+               linker_warning(prog, "%s shader varying %s not written "
+                              "by %s shader\n.",
+                              _mesa_shader_stage_to_string(consumer->Stage),
+                              var->name,
+                              _mesa_shader_stage_to_string(producer->Stage));
+            } else if (prog->Version <= 120) {
                /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
                 *
                 *     Only those varying variables used (i.e. read) in
@@ -1469,7 +1484,6 @@ assign_varying_locations(struct gl_context *ctx,
                 * write the variable for the FS to read it.  See
                 * "glsl1-varying read but not written" in piglit.
                 */
-
                linker_error(prog, "%s shader varying %s not written "
                             "by %s shader\n.",
                             _mesa_shader_stage_to_string(consumer->Stage),