From 5be5a033431597efc1f3b368a51a59e5b84e66ec Mon Sep 17 00:00:00 2001
From: Neil Roberts <neil@linux.intel.com>
Date: Fri, 25 Nov 2011 17:59:52 +0000
Subject: [PATCH] pipeline: Assume blend enabled when there are snippets

Whenever snippets are enabled we can't determine whether the final
color will be fully opaque so we just have to assume blending should
be enabled.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
---
 cogl/cogl-pipeline-layer.c         |  7 +++++++
 cogl/cogl-pipeline-state-private.h |  6 ++++++
 cogl/cogl-pipeline-state.c         | 23 ++++++++++++++++++-----
 cogl/cogl-pipeline.c               | 12 ++++++++++++
 4 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/cogl/cogl-pipeline-layer.c b/cogl/cogl-pipeline-layer.c
index 86e075089..76d17e743 100644
--- a/cogl/cogl-pipeline-layer.c
+++ b/cogl/cogl-pipeline-layer.c
@@ -78,6 +78,7 @@ _cogl_pipeline_layer_has_alpha (CoglPipelineLayer *layer)
                                         COGL_PIPELINE_LAYER_STATE_COMBINE);
   CoglPipelineLayerBigState *big_state = combine_authority->big_state;
   CoglPipelineLayer *tex_authority;
+  CoglPipelineLayer *snippets_authority;
 
   /* has_alpha maintains the alpha status for the GL_PREVIOUS layer */
 
@@ -112,6 +113,12 @@ _cogl_pipeline_layer_has_alpha (CoglPipelineLayer *layer)
       return TRUE;
     }
 
+  /* All bets are off if the layer contains any snippets */
+  snippets_authority = _cogl_pipeline_layer_get_authority
+    (layer, COGL_PIPELINE_LAYER_STATE_FRAGMENT_SNIPPETS);
+  if (!COGL_LIST_EMPTY (&snippets_authority->big_state->fragment_snippets))
+    return TRUE;
+
   return FALSE;
 }
 
diff --git a/cogl/cogl-pipeline-state-private.h b/cogl/cogl-pipeline-state-private.h
index 9a38e1104..2bc162dcd 100644
--- a/cogl/cogl-pipeline-state-private.h
+++ b/cogl/cogl-pipeline-state-private.h
@@ -37,6 +37,12 @@ _cogl_pipeline_has_vertex_snippets (CoglPipeline *pipeline);
 gboolean
 _cogl_pipeline_has_fragment_snippets (CoglPipeline *pipeline);
 
+gboolean
+_cogl_pipeline_has_non_layer_vertex_snippets (CoglPipeline *pipeline);
+
+gboolean
+_cogl_pipeline_has_non_layer_fragment_snippets (CoglPipeline *pipeline);
+
 void
 _cogl_pipeline_set_fog_state (CoglPipeline *pipeline,
                               const CoglPipelineFogState *fog_state);
diff --git a/cogl/cogl-pipeline-state.c b/cogl/cogl-pipeline-state.c
index 04caa918c..3477820c8 100644
--- a/cogl/cogl-pipeline-state.c
+++ b/cogl/cogl-pipeline-state.c
@@ -1632,7 +1632,7 @@ cogl_pipeline_add_fragment_hook (CoglPipeline *pipeline,
 }
 
 gboolean
-_cogl_pipeline_has_vertex_snippets (CoglPipeline *pipeline)
+_cogl_pipeline_has_non_layer_vertex_snippets (CoglPipeline *pipeline)
 {
   CoglPipeline *authority =
     _cogl_pipeline_get_authority (pipeline,
@@ -1641,6 +1641,22 @@ _cogl_pipeline_has_vertex_snippets (CoglPipeline *pipeline)
   return !COGL_LIST_EMPTY (&authority->big_state->vertex_snippets);
 }
 
+gboolean
+_cogl_pipeline_has_vertex_snippets (CoglPipeline *pipeline)
+{
+  return _cogl_pipeline_has_non_layer_vertex_snippets (pipeline);
+}
+
+gboolean
+_cogl_pipeline_has_non_layer_fragment_snippets (CoglPipeline *pipeline)
+{
+  CoglPipeline *authority =
+    _cogl_pipeline_get_authority (pipeline,
+                                  COGL_PIPELINE_STATE_FRAGMENT_SNIPPETS);
+
+  return !COGL_LIST_EMPTY (&authority->big_state->fragment_snippets);
+}
+
 static gboolean
 check_layer_has_fragment_snippet (CoglPipelineLayer *layer,
                                   void *user_data)
@@ -1662,12 +1678,9 @@ check_layer_has_fragment_snippet (CoglPipelineLayer *layer,
 gboolean
 _cogl_pipeline_has_fragment_snippets (CoglPipeline *pipeline)
 {
-  CoglPipeline *authority =
-    _cogl_pipeline_get_authority (pipeline,
-                                  COGL_PIPELINE_STATE_FRAGMENT_SNIPPETS);
   gboolean found_fragment_snippet = FALSE;
 
-  if (!COGL_LIST_EMPTY (&authority->big_state->fragment_snippets))
+  if (_cogl_pipeline_has_non_layer_fragment_snippets (pipeline))
     return TRUE;
 
   _cogl_pipeline_foreach_layer_internal (pipeline,
diff --git a/cogl/cogl-pipeline.c b/cogl/cogl-pipeline.c
index 2831b55f7..026c9c65b 100644
--- a/cogl/cogl-pipeline.c
+++ b/cogl/cogl-pipeline.c
@@ -761,6 +761,18 @@ _cogl_pipeline_needs_blending_enabled (CoglPipeline    *pipeline,
         return TRUE;
     }
 
+  if (changes & COGL_PIPELINE_STATE_FRAGMENT_SNIPPETS)
+    {
+      if (!_cogl_pipeline_has_non_layer_fragment_snippets (pipeline))
+        return TRUE;
+    }
+
+  if (changes & COGL_PIPELINE_STATE_VERTEX_SNIPPETS)
+    {
+      if (!_cogl_pipeline_has_non_layer_vertex_snippets (pipeline))
+        return TRUE;
+    }
+
   /* XXX: we should only need to look at these if lighting is enabled
    */
   if (changes & COGL_PIPELINE_STATE_LIGHTING)