[Cogl] [PATCH 2/2] progend-glsl: Fix handling of the builtin uniforms on non-GLES2

[Neil Roberts]

The ‘builtin uniforms’ are added to the GLSL code generated for the
GLES2 driver to implement missing fixed functionality such as the
builtin point sprite size and the alpha test reference. Previously the
code that accessed these was #ifdef'd to be compiled only when GLES2
was enabled. However since 2701b93f part of this code is now always
used even for non-GLES2 drivers. The code that accessed the builtin
uniforms array was however no longer #ifdef'd which meant that it
wouldn't compile any more if GLES2 was not enabled. This was further
broken becase the GL3 driver actually should be using the alpha test
uniform because that also does not provide any fixed functionality for
alpha testing.

To fix this the builtin uniform array is now always compiled in and
the code to access it is always used. A new member has been added to
the array to mark which private feature the uniform is used to
replace. That is checked before updating the uniform so that under
GLES2 it will update both uniforms but under GL3 it will only update
the alpha test reference.
---
 cogl/driver/gl/cogl-pipeline-progend-glsl.c | 51 ++++++++++++++---------------
 1 file changed, 25 insertions(+), 26 deletions(-)

diff --git a/cogl/driver/gl/cogl-pipeline-progend-glsl.c b/cogl/driver/gl/cogl-pipeline-progend-glsl.c
index 3300a2e..26504eb 100644
--- a/cogl/driver/gl/cogl-pipeline-progend-glsl.c
+++ b/cogl/driver/gl/cogl-pipeline-progend-glsl.c
@@ -50,10 +50,9 @@
 #include "cogl-framebuffer-private.h"
 #include "cogl-pipeline-progend-glsl-private.h"
 
-#ifdef HAVE_COGL_GLES2
-
 /* These are used to generalise updating some uniforms that are
-   required when building for GLES2 */
+   required when building for drivers missing some fixed function
+   state that we use */
 
 typedef void (* UpdateUniformFunc) (CoglPipeline *pipeline,
                                     int uniform_location,
@@ -69,20 +68,24 @@ typedef struct
   void *getter_func;
   UpdateUniformFunc update_func;
   CoglPipelineState change;
+
+  /* This builtin is only necessary if the following private feature
+   * is not implemented in the driver */
+  CoglPrivateFeatureFlags feature_replacement;
 } BuiltinUniformData;
 
 static BuiltinUniformData builtin_uniforms[] =
   {
     { "cogl_point_size_in",
       cogl_pipeline_get_point_size, update_float_uniform,
-      COGL_PIPELINE_STATE_POINT_SIZE },
+      COGL_PIPELINE_STATE_POINT_SIZE,
+      COGL_PRIVATE_FEATURE_BUILTIN_POINT_SIZE_UNIFORM },
     { "_cogl_alpha_test_ref",
       cogl_pipeline_get_alpha_test_reference, update_float_uniform,
-      COGL_PIPELINE_STATE_ALPHA_FUNC_REFERENCE }
+      COGL_PIPELINE_STATE_ALPHA_FUNC_REFERENCE,
+      COGL_PRIVATE_FEATURE_ALPHA_TEST }
   };
 
-#endif /* HAVE_COGL_GLES2 */
-
 const CoglPipelineProgend _cogl_pipeline_glsl_progend;
 
 typedef struct _UnitState
@@ -101,10 +104,8 @@ typedef struct
 
   GLuint program;
 
-#ifdef HAVE_COGL_GLES2
   unsigned long dirty_builtin_uniforms;
   GLint builtin_uniform_locations[G_N_ELEMENTS (builtin_uniforms)];
-#endif
 
   GLint modelview_uniform;
   GLint projection_uniform;
@@ -423,10 +424,9 @@ update_constants_cb (CoglPipeline *pipeline,
   return TRUE;
 }
 
-#ifdef HAVE_COGL_GLES2
-
 static void
-update_builtin_uniforms (CoglPipeline *pipeline,
+update_builtin_uniforms (CoglContext *context,
+                         CoglPipeline *pipeline,
                          GLuint gl_program,
                          CoglPipelineProgramState *program_state)
 {
@@ -436,7 +436,9 @@ update_builtin_uniforms (CoglPipeline *pipeline,
     return;
 
   for (i = 0; i < G_N_ELEMENTS (builtin_uniforms); i++)
-    if ((program_state->dirty_builtin_uniforms & (1 << i)) &&
+    if ((context->private_feature_flags &
+         builtin_uniforms[i].feature_replacement) == 0 &&
+        (program_state->dirty_builtin_uniforms & (1 << i)) &&
         program_state->builtin_uniform_locations[i] != -1)
       builtin_uniforms[i].update_func (pipeline,
                                        program_state
@@ -446,8 +448,6 @@ update_builtin_uniforms (CoglPipeline *pipeline,
   program_state->dirty_builtin_uniforms = 0;
 }
 
-#endif /* HAVE_COGL_GLES2 */
-
 typedef struct
 {
   CoglPipelineProgramState *program_state;
@@ -740,9 +740,11 @@ _cogl_pipeline_progend_glsl_end (CoglPipeline *pipeline,
       clear_flushed_matrix_stacks (program_state);
 
       for (i = 0; i < G_N_ELEMENTS (builtin_uniforms); i++)
-        GE_RET( program_state->builtin_uniform_locations[i], ctx,
-                glGetUniformLocation (gl_program,
-                                      builtin_uniforms[i].uniform_name) );
+        if ((ctx->private_feature_flags &
+             builtin_uniforms[i].feature_replacement) == 0)
+          GE_RET( program_state->builtin_uniform_locations[i], ctx,
+                  glGetUniformLocation (gl_program,
+                                        builtin_uniforms[i].uniform_name) );
 
       GE_RET( program_state->modelview_uniform, ctx,
               glGetUniformLocation (gl_program,
@@ -757,13 +759,11 @@ _cogl_pipeline_progend_glsl_end (CoglPipeline *pipeline,
                                     "cogl_modelview_projection_matrix") );
     }
 
-#ifdef HAVE_COGL_GLES2
   if (program_changed ||
       program_state->last_used_for_pipeline != pipeline)
     program_state->dirty_builtin_uniforms = ~(unsigned long) 0;
 
-  update_builtin_uniforms (pipeline, gl_program, program_state);
-#endif
+  update_builtin_uniforms (ctx, pipeline, gl_program, program_state);
 
   _cogl_pipeline_progend_glsl_flush_uniforms (pipeline,
                                               program_state,
@@ -784,14 +784,14 @@ _cogl_pipeline_progend_glsl_pre_change_notify (CoglPipeline *pipeline,
 
   if ((change & _cogl_pipeline_get_state_for_fragment_codegen (ctx)))
     dirty_program_state (pipeline);
-
-#ifdef HAVE_COGL_GLES2
-  else if (ctx->driver == COGL_DRIVER_GLES2)
+  else
     {
       int i;
 
       for (i = 0; i < G_N_ELEMENTS (builtin_uniforms); i++)
-        if ((change & builtin_uniforms[i].change))
+        if ((ctx->private_feature_flags &
+             builtin_uniforms[i].feature_replacement) == 0 &&
+            (change & builtin_uniforms[i].change))
           {
             CoglPipelineProgramState *program_state
               = get_program_state (pipeline);
@@ -800,7 +800,6 @@ _cogl_pipeline_progend_glsl_pre_change_notify (CoglPipeline *pipeline,
             return;
           }
     }
-#endif /* HAVE_COGL_GLES2 */
 }
 
 /* NB: layers are considered immutable once they have any dependants
-- 
1.7.11.3.g3c3efa5