[mutter/wip/carlosg/performance-improvements: 12/13] compositor: Avoid redoing the background pipeline on each paint() call

[Carlos Garnacho <carlosg src gnome org>]

commit 6704fa1d57577aa3648537be8ff5d141a8c50f22
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri May 5 14:14:28 2017 +0200

    compositor: Avoid redoing the background pipeline on each paint() call
    
    Just set filter quality, as that's the only thing depending on the viewport.

 src/compositor/meta-background-actor.c |   52 ++++++++++++++++++++++++--------
 1 files changed, 39 insertions(+), 13 deletions(-)
---
diff --git a/src/compositor/meta-background-actor.c b/src/compositor/meta-background-actor.c
index 132494d..ffdee9a 100644
--- a/src/compositor/meta-background-actor.c
+++ b/src/compositor/meta-background-actor.c
@@ -269,14 +269,12 @@ make_pipeline (PipelineFlags pipeline_flags)
 }
 
 static void
-setup_pipeline (MetaBackgroundActor   *self,
-                cairo_rectangle_int_t *actor_pixel_rect)
+setup_pipeline (MetaBackgroundActor *self)
 {
   MetaBackgroundActorPrivate *priv = self->priv;
   PipelineFlags pipeline_flags = 0;
   guint8 opacity;
   float color_component;
-  CoglPipelineFilter filter;
 
   opacity = clutter_actor_get_paint_opacity (CLUTTER_ACTOR (self));
   if (opacity < 255)
@@ -342,14 +340,6 @@ setup_pipeline (MetaBackgroundActor   *self,
                              color_component,
                              color_component,
                              opacity / 255.);
-
-  if (!priv->force_bilinear &&
-      meta_actor_painting_untransformed (actor_pixel_rect->width, actor_pixel_rect->height, NULL, NULL))
-    filter = COGL_PIPELINE_FILTER_NEAREST;
-  else
-    filter = COGL_PIPELINE_FILTER_LINEAR;
-
-  cogl_pipeline_set_layer_filters (priv->pipeline, 0, filter, filter);
 }
 
 static void
@@ -380,6 +370,22 @@ set_glsl_parameters (MetaBackgroundActor   *self,
 }
 
 static void
+set_pipeline_filter (MetaBackgroundActor   *self,
+                     cairo_rectangle_int_t *actor_pixel_rect)
+{
+  MetaBackgroundActorPrivate *priv = self->priv;
+  CoglPipelineFilter filter;
+
+  if (!priv->force_bilinear &&
+      meta_actor_painting_untransformed (actor_pixel_rect->width, actor_pixel_rect->height, NULL, NULL))
+    filter = COGL_PIPELINE_FILTER_NEAREST;
+  else
+    filter = COGL_PIPELINE_FILTER_LINEAR;
+
+  cogl_pipeline_set_layer_filters (priv->pipeline, 0, filter, filter);
+}
+
+static void
 paint_clipped_rectangle (CoglFramebuffer       *fb,
                          CoglPipeline          *pipeline,
                          cairo_rectangle_int_t *rect,
@@ -411,6 +417,26 @@ meta_background_actor_get_paint_volume (ClutterActor       *actor,
 }
 
 static void
+meta_background_actor_allocate (ClutterActor           *self,
+                                const ClutterActorBox  *box,
+                                ClutterAllocationFlags  flags)
+{
+  ClutterActorBox actor_box;
+  cairo_rectangle_int_t actor_pixel_rect;
+
+  CLUTTER_ACTOR_CLASS (meta_background_actor_parent_class)->allocate (self, box,
+                                                                      flags);
+  clutter_actor_get_content_box (self, &actor_box);
+  actor_pixel_rect.x = actor_box.x1;
+  actor_pixel_rect.y = actor_box.y1;
+  actor_pixel_rect.width = actor_box.x2 - actor_box.x1;
+  actor_pixel_rect.height = actor_box.y2 - actor_box.y1;
+
+  setup_pipeline (META_BACKGROUND_ACTOR (self));
+  set_glsl_parameters (META_BACKGROUND_ACTOR (self), &actor_pixel_rect);
+}
+
+static void
 meta_background_actor_paint (ClutterActor *actor)
 {
   MetaBackgroundActor *self = META_BACKGROUND_ACTOR (actor);
@@ -429,8 +455,7 @@ meta_background_actor_paint (ClutterActor *actor)
   actor_pixel_rect.width = actor_box.x2 - actor_box.x1;
   actor_pixel_rect.height = actor_box.y2 - actor_box.y1;
 
-  setup_pipeline (self, &actor_pixel_rect);
-  set_glsl_parameters (self, &actor_pixel_rect);
+  set_pipeline_filter (self, &actor_pixel_rect);
 
   /* Limit to how many separate rectangles we'll draw; beyond this just
    * fall back and draw the whole thing */
@@ -557,6 +582,7 @@ meta_background_actor_class_init (MetaBackgroundActorClass *klass)
   actor_class->get_preferred_width = meta_background_actor_get_preferred_width;
   actor_class->get_preferred_height = meta_background_actor_get_preferred_height;
   actor_class->get_paint_volume = meta_background_actor_get_paint_volume;
+  actor_class->allocate = meta_background_actor_allocate;
   actor_class->paint = meta_background_actor_paint;
 
   param_spec = g_param_spec_object ("meta-screen",