[mutter/gbsneto/red-damage: 207/207] clutter/stage-cogl: Disable buffer age when painting red damage

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

commit b19969b3f9a657fa560a46893ef86c726631bcbf
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Tue Dec 4 00:14:01 2018 -0200

    clutter/stage-cogl: Disable buffer age when painting red damage
    
    This is to ensure we're rendering a red damage area that actually
    represents what is being damaged.
    
    Fixes an always-fullscreen red damage on bare metal Wayland and
    GNOME Shell.

 clutter/clutter/cogl/clutter-stage-cogl.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)
---
diff --git a/clutter/clutter/cogl/clutter-stage-cogl.c b/clutter/clutter/cogl/clutter-stage-cogl.c
index 94f330dea..ad9dec304 100644
--- a/clutter/clutter/cogl/clutter-stage-cogl.c
+++ b/clutter/clutter/cogl/clutter-stage-cogl.c
@@ -576,6 +576,15 @@ calculate_scissor_region (cairo_rectangle_int_t *fb_clip_region,
   };
 }
 
+static inline gboolean
+is_buffer_age_enabled (void)
+{
+  /* Buffer age is disabled when running with CLUTTER_PAINT=damage-region,
+   * to ensure the red damage represents the currently damaged area */
+  return !(clutter_paint_debug_flags & CLUTTER_DEBUG_PAINT_DAMAGE_REGION) &&
+         cogl_clutter_winsys_has_feature (COGL_WINSYS_FEATURE_BUFFER_AGE);
+}
+
 static gboolean
 clutter_stage_cogl_redraw_view (ClutterStageWindow *stage_window,
                                 ClutterStageView   *view)
@@ -613,9 +622,7 @@ clutter_stage_cogl_redraw_view (ClutterStageWindow *stage_window,
     cogl_is_onscreen (fb) &&
     cogl_clutter_winsys_has_feature (COGL_WINSYS_FEATURE_SWAP_REGION);
 
-  has_buffer_age =
-    cogl_is_onscreen (fb) &&
-    cogl_clutter_winsys_has_feature (COGL_WINSYS_FEATURE_BUFFER_AGE);
+  has_buffer_age = cogl_is_onscreen (fb) && is_buffer_age_enabled ();
 
   /* NB: a zero width redraw clip == full stage redraw */
   if (stage_cogl->bounding_redraw_clip.width == 0)
@@ -946,7 +953,7 @@ clutter_stage_cogl_get_dirty_pixel (ClutterStageWindow *stage_window,
   CoglFramebuffer *framebuffer = clutter_stage_view_get_framebuffer (view);
   gboolean has_buffer_age =
     cogl_is_onscreen (framebuffer) &&
-    cogl_clutter_winsys_has_feature (COGL_WINSYS_FEATURE_BUFFER_AGE);
+    is_buffer_age_enabled ();
   float fb_scale;
   gboolean scale_is_fractional;