compositor: Keep a z-ordered list of planes

This let us clear a plane's opaque region without adding code in the
backend, and will be used in a following commit to change how we track
damage.

src/compositor-drm.c

@@ -920,26 +920,10 @@ drm_assign_planes(struct weston_output *output)
 {
 	struct drm_compositor *c =
 		(struct drm_compositor *) output->compositor;
-	struct drm_output *drm_output = (struct drm_output *) output;
-	struct drm_sprite *s;
 	struct weston_surface *es, *next;
 	pixman_region32_t overlap, surface_overlap;
 	struct weston_plane *primary, *next_plane;
 
-	/* Reset the opaque region of the planes */
-	pixman_region32_fini(&drm_output->cursor_plane.opaque);
-	pixman_region32_init(&drm_output->cursor_plane.opaque);
-	pixman_region32_fini(&drm_output->fb_plane.opaque);
-	pixman_region32_init(&drm_output->fb_plane.opaque);
-
-	wl_list_for_each (s, &c->sprite_list, link) {
-		if (!drm_sprite_crtc_supported(output, s->possible_crtcs))
-			continue;
-
-		pixman_region32_fini(&s->plane.opaque);
-		pixman_region32_init(&s->plane.opaque);
-	}
-
 	/*
 	 * Find a surface for each sprite in the output using some heuristics:
 	 * 1) size
@@ -1643,6 +1627,10 @@ create_output_for_connector(struct drm_compositor *ec,
 	weston_plane_init(&output->cursor_plane, 0, 0);
 	weston_plane_init(&output->fb_plane, 0, 0);
 
+	weston_compositor_stack_plane(&ec->base, &output->cursor_plane, NULL);
+	weston_compositor_stack_plane(&ec->base, &output->fb_plane,
+				      &ec->base.primary_plane);
+
 	weston_log("Output %s, (connector %d, crtc %d)\n",
 		   output->name, output->connector_id, output->crtc_id);
 	wl_list_for_each(m, &output->base.mode_list, link)
@@ -1716,6 +1704,8 @@ create_sprites(struct drm_compositor *ec)
 		       plane->count_formats * sizeof(plane->formats[0]));
 		drmModeFreePlane(plane);
 		weston_plane_init(&sprite->plane, 0, 0);
+		weston_compositor_stack_plane(&ec->base, &sprite->plane,
+					      &ec->base.primary_plane);
 
 		wl_list_insert(&ec->sprite_list, &sprite->link);
 	}

src/compositor.c

@@ -1096,6 +1096,38 @@ surface_accumulate_damage(struct weston_surface *surface,
 	pixman_region32_union(opaque, opaque, &surface->transform.opaque);
 }
 
+static void
+compositor_accumulate_damage(struct weston_compositor *ec)
+{
+	struct weston_plane *plane;
+	struct weston_surface *es;
+	pixman_region32_t opaque;
+
+	pixman_region32_init(&opaque);
+
+	wl_list_for_each(plane, &ec->plane_list, link) {
+		pixman_region32_fini(&plane->opaque);
+		pixman_region32_init(&plane->opaque);
+	}
+
+	wl_list_for_each(es, &ec->surface_list, link) {
+		surface_accumulate_damage(es, &opaque);
+
+		/* Both the renderer and the backend have seen the buffer
+		 * by now. If renderer needs the buffer, it has its own
+		 * reference set. If the backend wants to keep the buffer
+		 * around for migrating the surface into a non-primary plane
+		 * later, keep_buffer is true. Otherwise, drop the core
+		 * reference now, and allow early buffer release. This enables
+		 * clients to use single-buffering.
+		 */
+		if (!es->keep_buffer)
+			weston_buffer_reference(&es->buffer_ref, NULL);
+	}
+
+	pixman_region32_fini(&opaque);
+}
+
 static void
 weston_output_repaint(struct weston_output *output, uint32_t msecs)
 {
@@ -1105,7 +1137,7 @@ weston_output_repaint(struct weston_output *output, uint32_t msecs)
 	struct weston_animation *animation, *next;
 	struct weston_frame_callback *cb, *cnext;
 	struct wl_list frame_callback_list;
-	pixman_region32_t opaque, output_damage;
+	pixman_region32_t output_damage;
 
 	weston_compositor_update_drag_surfaces(ec);
 
@@ -1130,27 +1162,7 @@ weston_output_repaint(struct weston_output *output, uint32_t msecs)
 		wl_list_for_each(es, &ec->surface_list, link)
 			weston_surface_move_to_plane(es, &ec->primary_plane);
 
-	pixman_region32_init(&opaque);
-
-	pixman_region32_fini(&ec->primary_plane.opaque);
-	pixman_region32_init(&ec->primary_plane.opaque);
-
-	wl_list_for_each(es, &ec->surface_list, link) {
-		surface_accumulate_damage(es, &opaque);
-
-		/* Both the renderer and the backend have seen the buffer
-		 * by now. If renderer needs the buffer, it has its own
-		 * reference set. If the backend wants to keep the buffer
-		 * around for migrating the surface into a non-primary plane
-		 * later, keep_buffer is true. Otherwise, drop the core
-		 * reference now, and allow early buffer release. This enables
-		 * clients to use single-buffering.
-		 */
-		if (!es->keep_buffer)
-			weston_buffer_reference(&es->buffer_ref, NULL);
-	}
-
-	pixman_region32_fini(&opaque);
+	compositor_accumulate_damage(ec);
 
 	pixman_region32_init(&output_damage);
 	pixman_region32_intersect(&output_damage,
@@ -1672,6 +1684,17 @@ weston_plane_release(struct weston_plane *plane)
 	pixman_region32_fini(&plane->opaque);
 }
 
+WL_EXPORT void
+weston_compositor_stack_plane(struct weston_compositor *ec,
+			      struct weston_plane *plane,
+			      struct weston_plane *above)
+{
+	if (above)
+		wl_list_insert(above->link.prev, &plane->link);
+	else
+		wl_list_insert(&ec->plane_list, &plane->link);
+}
+
 static  void
 weston_seat_update_drag_surface(struct weston_seat *seat, int dx, int dy);
 
@@ -3059,6 +3082,7 @@ weston_compositor_init(struct weston_compositor *ec,
 		return -1;
 
 	wl_list_init(&ec->surface_list);
+	wl_list_init(&ec->plane_list);
 	wl_list_init(&ec->layer_list);
 	wl_list_init(&ec->seat_list);
 	wl_list_init(&ec->output_list);
@@ -3068,6 +3092,7 @@ weston_compositor_init(struct weston_compositor *ec,
 	wl_list_init(&ec->debug_binding_list);
 
 	weston_plane_init(&ec->primary_plane, 0, 0);
+	weston_compositor_stack_plane(ec, &ec->primary_plane, NULL);
 
 	if (weston_compositor_xkb_init(ec, &xkb_names) < 0)
 		return -1;

src/compositor.h

@@ -269,6 +269,7 @@ struct weston_plane {
 	pixman_region32_t damage;
 	pixman_region32_t opaque;
 	int32_t x, y;
+	struct wl_list link;
 };
 
 struct weston_renderer {
@@ -314,6 +315,7 @@ struct weston_compositor {
 	struct wl_list seat_list;
 	struct wl_list layer_list;
 	struct wl_list surface_list;
+	struct wl_list plane_list;
 	struct wl_list key_binding_list;
 	struct wl_list button_binding_list;
 	struct wl_list axis_binding_list;
@@ -576,6 +578,11 @@ weston_plane_init(struct weston_plane *plane, int32_t x, int32_t y);
 void
 weston_plane_release(struct weston_plane *plane);
 
+void
+weston_compositor_stack_plane(struct weston_compositor *ec,
+			      struct weston_plane *plane,
+			      struct weston_plane *above);
+
 void
 weston_output_finish_frame(struct weston_output *output, uint32_t msecs);
 void