paint-node: Get the framebuffer from the root node

The PaintNode hierarchy should have the ability to retrieve the
current active framebuffer by itself, instead of asking Cogl using the
global state API.

In order to do this, we ask the root node of a PaintNode graph for the
active framebuffer. In the current, 1.x-compatibility mode we have two
potential root node types: ClutterRootNode, used by ClutterStage; and
ClutterDummyNode, used a local root for each actor. The former takes a
framebuffer as part of its construction; the latter takes the actor that
acts as the local top-level during the actor's paint sequence, which
means we can get the active framebuffer from the stage associated to the
actor.

By keeping track of the active framebuffer on the node themselves we can
drop the usage of cogl_get_draw_framebuffer() in their implementation.

clutter/clutter-paint-node-private.h

@@ -68,6 +68,8 @@ struct _ClutterPaintNodeClass
   void     (* post_draw) (ClutterPaintNode *node);
 
   JsonNode*(* serialize) (ClutterPaintNode *node);
+
+  CoglFramebuffer *(* get_framebuffer) (ClutterPaintNode *node);
 };
 
 #define PAINT_OP_INIT   { PAINT_OP_INVALID }
@@ -137,6 +139,8 @@ G_GNUC_INTERNAL
 ClutterPaintNode *      clutter_paint_node_get_last_child               (ClutterPaintNode      *node);
 G_GNUC_INTERNAL
 ClutterPaintNode *      clutter_paint_node_get_parent                   (ClutterPaintNode      *node);
+G_GNUC_INTERNAL
+CoglFramebuffer *       clutter_paint_node_get_framebuffer              (ClutterPaintNode      *node);
 
 #define CLUTTER_TYPE_LAYER_NODE                 (_clutter_layer_node_get_type ())
 #define CLUTTER_LAYER_NODE(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), CLUTTER_TYPE_LAYER_NODE, ClutterLayerNode))

clutter/clutter-paint-node.c

@@ -1123,3 +1123,31 @@ _clutter_paint_node_create (GType gtype)
 
   return (gpointer) g_type_create_instance (gtype);
 }
+
+static ClutterPaintNode *
+clutter_paint_node_get_root (ClutterPaintNode *node)
+{
+  ClutterPaintNode *iter;
+
+  iter = node;
+  while (iter != NULL && iter->parent != NULL)
+    iter = iter->parent;
+
+  return iter;
+}
+
+CoglFramebuffer *
+clutter_paint_node_get_framebuffer (ClutterPaintNode *node)
+{
+  ClutterPaintNode *root = clutter_paint_node_get_root (node);
+  ClutterPaintNodeClass *klass;
+
+  if (root == NULL)
+    return NULL;
+
+  klass = CLUTTER_PAINT_NODE_GET_CLASS (root);
+  if (klass->get_framebuffer != NULL)
+    return klass->get_framebuffer (root);
+
+  return cogl_get_draw_framebuffer ();
+}

clutter/clutter-paint-nodes.c

@@ -135,6 +135,14 @@ clutter_root_node_finalize (ClutterPaintNode *node)
   CLUTTER_PAINT_NODE_CLASS (clutter_root_node_parent_class)->finalize (node);
 }
 
+static CoglFramebuffer *
+clutter_root_node_get_framebuffer (ClutterPaintNode *node)
+{
+  ClutterRootNode *rnode = (ClutterRootNode *) node;
+
+  return rnode->framebuffer;
+}
+
 static void
 clutter_root_node_class_init (ClutterRootNodeClass *klass)
 {
@@ -143,6 +151,7 @@ clutter_root_node_class_init (ClutterRootNodeClass *klass)
   node_class->pre_draw = clutter_root_node_pre_draw;
   node_class->post_draw = clutter_root_node_post_draw;
   node_class->finalize = clutter_root_node_finalize;
+  node_class->get_framebuffer = clutter_root_node_get_framebuffer;
 }
 
 static void
@@ -262,6 +271,7 @@ struct _ClutterDummyNode
   ClutterPaintNode parent_instance;
 
   ClutterActor *actor;
+  CoglFramebuffer *framebuffer;
 };
 
 G_DEFINE_TYPE (ClutterDummyNode, clutter_dummy_node, CLUTTER_TYPE_PAINT_NODE)
@@ -296,6 +306,14 @@ clutter_dummy_node_serialize (ClutterPaintNode *node)
   return res;
 }
 
+static CoglFramebuffer *
+clutter_dummy_node_get_framebuffer (ClutterPaintNode *node)
+{
+  ClutterDummyNode *dnode = (ClutterDummyNode *) node;
+
+  return dnode->framebuffer;
+}
+
 static void
 clutter_dummy_node_class_init (ClutterDummyNodeClass *klass)
 {
@@ -303,6 +321,7 @@ clutter_dummy_node_class_init (ClutterDummyNodeClass *klass)
 
   node_class->pre_draw = clutter_dummy_node_pre_draw;
   node_class->serialize = clutter_dummy_node_serialize;
+  node_class->get_framebuffer = clutter_dummy_node_get_framebuffer;
 }
 
 static void
@@ -314,10 +333,13 @@ ClutterPaintNode *
 _clutter_dummy_node_new (ClutterActor *actor)
 {
   ClutterPaintNode *res;
+  ClutterDummyNode *dnode;
 
   res = _clutter_paint_node_create (_clutter_dummy_node_get_type ());
 
-  ((ClutterDummyNode *) res)->actor = actor;
+  dnode = (ClutterDummyNode *) res;
+  dnode->actor = actor;
+  dnode->framebuffer = _clutter_actor_get_active_framebuffer (actor);
 
   return res;
 }
@@ -378,6 +400,7 @@ static void
 clutter_pipeline_node_draw (ClutterPaintNode *node)
 {
   ClutterPipelineNode *pnode = CLUTTER_PIPELINE_NODE (node);
+  CoglFramebuffer *fb;
   guint i;
 
   if (pnode->pipeline == NULL)
@@ -386,6 +409,8 @@ clutter_pipeline_node_draw (ClutterPaintNode *node)
   if (node->operations == NULL)
     return;
 
+  fb = clutter_paint_node_get_framebuffer (node);
+
   for (i = 0; i < node->operations->len; i++)
     {
       const ClutterPaintOperation *op;
@@ -413,12 +438,9 @@ clutter_pipeline_node_draw (ClutterPaintNode *node)
           break;
 
         case PAINT_OP_PRIMITIVE:
-          {
-            CoglFramebuffer *fb = cogl_get_draw_framebuffer ();
-
-            cogl_framebuffer_draw_primitive (fb, pnode->pipeline,
-                                             op->op.primitive);
-          }
+          cogl_framebuffer_draw_primitive (fb,
+                                           pnode->pipeline,
+                                           op->op.primitive);
           break;
         }
     }
@@ -764,7 +786,7 @@ clutter_text_node_draw (ClutterPaintNode *node)
   if (node->operations == NULL)
     return;
 
-  fb = cogl_get_draw_framebuffer ();
+  fb = clutter_paint_node_get_framebuffer (node);
 
   pango_layout_get_pixel_extents (tnode->layout, NULL, &extents);
 
@@ -948,7 +970,7 @@ clutter_clip_node_pre_draw (ClutterPaintNode *node)
   if (node->operations == NULL)
     return FALSE;
 
-  fb = cogl_get_draw_framebuffer ();
+  fb = clutter_paint_node_get_framebuffer (node);
 
   for (i = 0; i < node->operations->len; i++)
     {
@@ -990,7 +1012,7 @@ clutter_clip_node_post_draw (ClutterPaintNode *node)
   if (node->operations == NULL)
     return;
 
-  fb = cogl_get_draw_framebuffer ();
+  fb = clutter_paint_node_get_framebuffer (node);
 
   for (i = 0; i < node->operations->len; i++)
     {