[mutter/gbsneto/new-nodes: 45/45] clutter/actor: Always paint using paint nodes

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit cd2ee4421670e40e0eee8519af42b7477c7d8eed
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Oct 17 21:02:34 2019 +0200

    clutter/actor: Always paint using paint nodes
    
    Make ClutterActor paint using ClutterTransformNode, ClutterClip
    node, and ClutterActorNode. Essencially, the actor node is a
    replacement for clutter_actor_continue_paint().
    
    An interesting aspect of this commit is that the order of the
    operations is reversed to be preserved.
    
    Before being able to remove the dummy node hack, we'll need to
    make ClutterEffects compatible with paint nodes first -- and
    naturally, that's enough content for its own merge request.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/872

 clutter/clutter/clutter-actor.c | 93 +++++++++++++++++++----------------------
 1 file changed, 42 insertions(+), 51 deletions(-)
---
diff --git a/clutter/clutter/clutter-actor.c b/clutter/clutter/clutter-actor.c
index 207a5ef30..101f4bf0f 100644
--- a/clutter/clutter/clutter-actor.c
+++ b/clutter/clutter/clutter-actor.c
@@ -3876,10 +3876,11 @@ clutter_actor_paint_node (ClutterActor     *actor,
 void
 clutter_actor_paint (ClutterActor *self)
 {
+  g_autoptr (ClutterPaintNode) actor_node = NULL;
+  g_autoptr (ClutterPaintNode) root_node = NULL;
   ClutterActorPrivate *priv;
   ClutterActorBox clip;
   gboolean clip_set = FALSE;
-  ClutterStage *stage;
 
   g_return_if_fail (CLUTTER_IS_ACTOR (self));
 
@@ -3906,22 +3907,51 @@ clutter_actor_paint (ClutterActor *self)
 
   clutter_actor_ensure_resource_scale (self);
 
-  stage = (ClutterStage *) _clutter_actor_get_stage_internal (self);
-
   /* mark that we are in the paint process */
   CLUTTER_SET_PRIVATE_FLAGS (self, CLUTTER_IN_PAINT);
 
-  cogl_push_matrix ();
+  actor_node = clutter_actor_node_new (self);
+  root_node = clutter_paint_node_ref (actor_node);
+
+  if (priv->has_clip)
+    {
+      clip.x1 = priv->clip.origin.x;
+      clip.y1 = priv->clip.origin.y;
+      clip.x2 = priv->clip.origin.x + priv->clip.size.width;
+      clip.y2 = priv->clip.origin.y + priv->clip.size.height;
+      clip_set = TRUE;
+    }
+  else if (priv->clip_to_allocation)
+    {
+      clip.x1 = 0.f;
+      clip.y1 = 0.f;
+      clip.x2 = priv->allocation.x2 - priv->allocation.x1;
+      clip.y2 = priv->allocation.y2 - priv->allocation.y1;
+      clip_set = TRUE;
+    }
+
+  if (clip_set)
+    {
+      ClutterPaintNode *clip_node;
+
+      clip_node = clutter_clip_node_new ();
+      clutter_paint_node_add_rectangle (clip_node, &clip);
+      clutter_paint_node_add_child (clip_node, root_node);
+
+      root_node = g_steal_pointer (&clip_node);
+    }
 
   if (priv->enable_model_view_transform)
     {
-      CoglMatrix matrix;
+      ClutterPaintNode *transform_node;
+      CoglMatrix transform;
 
-      /* XXX: It could be better to cache the modelview with the actor
-       * instead of progressively building up the transformations on
-       * the matrix stack every time we paint. */
-      cogl_get_modelview_matrix (&matrix);
-      _clutter_actor_apply_modelview_transform (self, &matrix);
+      clutter_actor_get_transform (self, &transform);
+
+      transform_node = clutter_transform_node_new (&transform);
+      clutter_paint_node_add_child (transform_node, root_node);
+
+      root_node = g_steal_pointer (&transform_node);
 
 #ifdef CLUTTER_ENABLE_DEBUG
       /* Catch when out-of-band transforms have been made by actors not as part
@@ -3933,7 +3963,7 @@ clutter_actor_paint (ClutterActor *self)
           _clutter_actor_get_relative_transformation_matrix (self, NULL,
                                                              &expected_matrix);
 
-          if (!cogl_matrix_equal (&matrix, &expected_matrix))
+          if (!cogl_matrix_equal (&transform, &expected_matrix))
             {
               GString *buf = g_string_sized_new (1024);
               ClutterActor *parent;
@@ -3960,36 +3990,6 @@ clutter_actor_paint (ClutterActor *self)
             }
         }
 #endif /* CLUTTER_ENABLE_DEBUG */
-
-      cogl_set_modelview_matrix (&matrix);
-    }
-
-  if (priv->has_clip)
-    {
-      clip.x1 = priv->clip.origin.x;
-      clip.y1 = priv->clip.origin.y;
-      clip.x2 = priv->clip.origin.x + priv->clip.size.width;
-      clip.y2 = priv->clip.origin.y + priv->clip.size.height;
-      clip_set = TRUE;
-    }
-  else if (priv->clip_to_allocation)
-    {
-      clip.x1 = 0.f;
-      clip.y1 = 0.f;
-      clip.x2 = priv->allocation.x2 - priv->allocation.x1;
-      clip.y2 = priv->allocation.y2 - priv->allocation.y1;
-      clip_set = TRUE;
-    }
-
-  if (clip_set)
-    {
-      CoglFramebuffer *fb = _clutter_stage_get_active_framebuffer (stage);
-
-      cogl_framebuffer_push_rectangle_clip (fb,
-                                            clip.x1,
-                                            clip.y1,
-                                            clip.x2,
-                                            clip.y2);
     }
 
   /* We check whether we need to add the flatten effect before
@@ -4054,7 +4054,7 @@ clutter_actor_paint (ClutterActor *self)
     priv->next_effect_to_paint =
       _clutter_meta_group_peek_metas (priv->effects);
 
-  clutter_actor_continue_paint (self);
+  clutter_paint_node_paint (root_node);
 
   if (G_UNLIKELY (clutter_paint_debug_flags & CLUTTER_DEBUG_PAINT_VOLUMES))
     _clutter_actor_draw_paint_volume (self);
@@ -4064,15 +4064,6 @@ clutter_actor_paint (ClutterActor *self)
   priv->is_dirty = FALSE;
 
 done:
-  if (clip_set)
-    {
-      CoglFramebuffer *fb = _clutter_stage_get_active_framebuffer (stage);
-
-      cogl_framebuffer_pop_clip (fb);
-    }
-
-  cogl_pop_matrix ();
-
   /* paint sequence complete */
   CLUTTER_UNSET_PRIVATE_FLAGS (self, CLUTTER_IN_PAINT);
 }