[mutter] shaped-texture: Simplify pipeline creation

[Jasper St. Pierre <jstpierre src gnome org>]

commit 57258dc1d4718ea7d9967b7f4a95f683df0deedb
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Aug 27 16:03:42 2013 -0400

    shaped-texture: Simplify pipeline creation
    
    Split out pipeline creation to a separate function so that we don't
    have so much dense code in the paint function itself, and remove some
    indentation levels.
    
    Also, don't use our own template for the unmasked pipeline, since it
    has nothing different from the default pipeline template.
    
    We also don't store the pipelines anymore since their creation isn't
    really helping us; we set the mask texture and paint texture on every
    paint anyway.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706930

 src/compositor/meta-shaped-texture.c |   72 ++++++++++++++--------------------
 1 files changed, 30 insertions(+), 42 deletions(-)
---
diff --git a/src/compositor/meta-shaped-texture.c b/src/compositor/meta-shaped-texture.c
index 385f80a..83c227c 100644
--- a/src/compositor/meta-shaped-texture.c
+++ b/src/compositor/meta-shaped-texture.c
@@ -68,8 +68,6 @@ struct _MetaShapedTexturePrivate
   Pixmap pixmap;
   CoglTexturePixmapX11 *texture;
   CoglTexture *mask_texture;
-  CoglPipeline *pipeline;
-  CoglPipeline *pipeline_unshaped;
 
   cairo_region_t *clip_region;
 
@@ -118,8 +116,6 @@ meta_shaped_texture_dispose (GObject *object)
     meta_texture_tower_free (priv->paint_tower);
   priv->paint_tower = NULL;
 
-  g_clear_pointer (&priv->pipeline, cogl_object_unref);
-  g_clear_pointer (&priv->pipeline_unshaped, cogl_object_unref);
   g_clear_pointer (&priv->texture, cogl_object_unref);
 
   meta_shaped_texture_set_mask_texture (self, NULL);
@@ -128,6 +124,27 @@ meta_shaped_texture_dispose (GObject *object)
   G_OBJECT_CLASS (meta_shaped_texture_parent_class)->dispose (object);
 }
 
+static CoglPipeline *
+get_unmasked_pipeline (CoglContext *ctx)
+{
+  return cogl_pipeline_new (ctx);
+}
+
+static CoglPipeline *
+get_masked_pipeline (CoglContext *ctx)
+{
+  static CoglPipeline *template = NULL;
+  if (G_UNLIKELY (template == NULL))
+    {
+      template = cogl_pipeline_new (ctx);
+      cogl_pipeline_set_layer_combine (template, 1,
+                                       "RGBA = MODULATE (PREVIOUS, TEXTURE[A])",
+                                       NULL);
+    }
+
+  return cogl_pipeline_copy (template);
+}
+
 static void
 meta_shaped_texture_paint (ClutterActor *actor)
 {
@@ -136,10 +153,7 @@ meta_shaped_texture_paint (ClutterActor *actor)
   CoglTexture *paint_tex;
   guint tex_width, tex_height;
   ClutterActorBox alloc;
-
-  static CoglPipeline *pipeline_template = NULL;
-  static CoglPipeline *pipeline_unshaped_template = NULL;
-
+  CoglContext *ctx;
   CoglPipeline *pipeline;
 
   if (priv->clip_region && cairo_region_is_empty (priv->clip_region))
@@ -177,38 +191,15 @@ meta_shaped_texture_paint (ClutterActor *actor)
   if (tex_width == 0 || tex_height == 0) /* no contents yet */
     return;
 
+  ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
+
   if (priv->mask_texture == NULL)
     {
-      /* Use a single-layer texture if we don't have a mask. */
-
-      if (priv->pipeline_unshaped == NULL)
-        {
-          if (G_UNLIKELY (pipeline_unshaped_template == NULL))
-            {
-              CoglContext *ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
-              pipeline_unshaped_template = cogl_pipeline_new (ctx);
-            }
-
-          priv->pipeline_unshaped = cogl_pipeline_copy (pipeline_unshaped_template);
-        }
-      pipeline = priv->pipeline_unshaped;
+      pipeline = get_unmasked_pipeline (ctx);
     }
   else
     {
-      if (priv->pipeline == NULL)
-       {
-          if (G_UNLIKELY (pipeline_template == NULL))
-           {
-              CoglContext *ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
-             pipeline_template =  cogl_pipeline_new (ctx);
-             cogl_pipeline_set_layer_combine (pipeline_template, 1,
-                                               "RGBA = MODULATE (PREVIOUS, TEXTURE[A])",
-                                               NULL);
-           }
-         priv->pipeline = cogl_pipeline_copy (pipeline_template);
-       }
-      pipeline = priv->pipeline;
-
+      pipeline = get_masked_pipeline (ctx);
       cogl_pipeline_set_layer_texture (pipeline, 1, priv->mask_texture);
     }
 
@@ -269,13 +260,16 @@ meta_shaped_texture_paint (ClutterActor *actor)
                                                        &coords[0], 8);
             }
 
-         return;
+          goto out;
        }
     }
 
   cogl_rectangle (0, 0,
                  alloc.x2 - alloc.x1,
                  alloc.y2 - alloc.y1);
+
+ out:
+  cogl_object_unref (pipeline);
 }
 
 static void
@@ -502,12 +496,6 @@ set_cogl_texture (MetaShapedTexture    *stex,
 
   priv->texture = cogl_tex;
 
-  if (priv->pipeline != NULL)
-    cogl_pipeline_set_layer_texture (priv->pipeline, 0, COGL_TEXTURE (cogl_tex));
-
-  if (priv->pipeline_unshaped != NULL)
-    cogl_pipeline_set_layer_texture (priv->pipeline_unshaped, 0, COGL_TEXTURE (cogl_tex));
-
   if (cogl_tex != NULL)
     {
       width = cogl_texture_get_width (COGL_TEXTURE (cogl_tex));