stage-window: make it possible to damage the back buffer

This allows us to report to the backend that the stage's back buffer has
been trashed while handling picking. If the backend is keeping track of
the contents of back buffers so it can minimize how much of the stage is
redrawn then it needs to know when we do pick renders so it can
invalidate the back buffer.

4 files changed, 28 insertions, 0 deletions

diff --git a/clutter/clutter-stage-window.c b/clutter/clutter-stage-window.c
index a438d5098..2580bf4ab 100644
--- a/clutter/clutter-stage-window.c
+++ b/clutter/clutter-stage-window.c
@@ -192,3 +192,15 @@ _clutter_stage_window_redraw (ClutterStageWindow *window)
   if (iface->redraw)
     iface->redraw (window);
 }
+
+void
+_clutter_stage_window_dirty_back_buffer (ClutterStageWindow *window)
+{
+  ClutterStageWindowIface *iface;
+
+  g_return_if_fail (CLUTTER_IS_STAGE_WINDOW (window));
+
+  iface = CLUTTER_STAGE_WINDOW_GET_IFACE (window);
+  if (iface->dirty_back_buffer)
+    iface->dirty_back_buffer (window);
+}
diff --git a/clutter/clutter-stage-window.h b/clutter/clutter-stage-window.h
index d616d2b11..4d642a319 100644
--- a/clutter/clutter-stage-window.h
+++ b/clutter/clutter-stage-window.h
@@ -68,6 +68,8 @@ struct _ClutterStageWindowIface
                                            gboolean            accept_focus);
 
   void          (* redraw)                (ClutterStageWindow *stage_window);
+
+  void          (* dirty_back_buffer)     (ClutterStageWindow *stage_window);
 };
 
 GType clutter_stage_window_get_type (void) G_GNUC_CONST;
@@ -107,6 +109,8 @@ void          _clutter_stage_window_set_accept_focus      (ClutterStageWindow *w
 
 void          _clutter_stage_window_redraw                (ClutterStageWindow *window);
 
+void          _clutter_stage_window_dirty_back_buffer     (ClutterStageWindow *window);
+
 G_END_DECLS
 
 #endif /* __CLUTTER_STAGE_WINDOW_H__ */
diff --git a/clutter/clutter-stage.c b/clutter/clutter-stage.c
index bb2b3456a..bf5564707 100644
--- a/clutter/clutter-stage.c
+++ b/clutter/clutter-stage.c
@@ -1356,6 +1356,10 @@ _clutter_stage_do_pick (ClutterStage   *stage,
   context->pick_mode = CLUTTER_PICK_NONE;
   CLUTTER_TIMER_STOP (_clutter_uprof_context, pick_paint);
 
+  /* Notify the backend that we have trashed the contents of
+   * the back buffer... */
+  _clutter_stage_window_dirty_back_buffer (priv->impl);
+
   if (is_clipped)
     {
       if (G_LIKELY (!(clutter_pick_debug_flags &
diff --git a/clutter/glx/clutter-stage-glx.c b/clutter/glx/clutter-stage-glx.c
index e3442fc00..a2ae2dabe 100644
--- a/clutter/glx/clutter-stage-glx.c
+++ b/clutter/glx/clutter-stage-glx.c
@@ -639,6 +639,13 @@ clutter_stage_glx_redraw (ClutterStageWindow *stage_window)
 }
 
 static void
+clutter_stage_glx_dirty_back_buffer (ClutterStageWindow *stage_window)
+{
+  ClutterStageGLX *stage_glx = CLUTTER_STAGE_GLX (stage_window);
+  stage_glx->n_old_redraw_clips = 0;
+}
+
+static void
 clutter_stage_window_iface_init (ClutterStageWindowIface *iface)
 {
   clutter_stage_window_parent_iface = g_type_interface_peek_parent (iface);
@@ -651,6 +658,7 @@ clutter_stage_window_iface_init (ClutterStageWindowIface *iface)
   iface->has_redraw_clips = clutter_stage_glx_has_redraw_clips;
   iface->ignoring_redraw_clips = clutter_stage_glx_ignoring_redraw_clips;
   iface->redraw = clutter_stage_glx_redraw;
+  iface->dirty_back_buffer = clutter_stage_glx_dirty_back_buffer;
 
   /* the rest is inherited from ClutterStageX11 */
 }