clutter: Introduce geometric picking

Currently, Clutter does picking by drawing with Cogl and reading
the pixel that's beneath the given point. Since Cogl has a journal
that records drawing operations, and has optimizations to read a
single pixel from a list of rectangle, it would be expected that
we would hit this fast path and not flush the journal while picking.

However, that's not the case: dithering, clipping with scissors, etc,
can all flush the journal, issuing commands to the GPU and making
picking slow. On NVidia-based systems, this glReadPixels() call is
extremely costly.

Introduce geometric picking, and avoid using the Cogl journal entirely.
Do this by introducing a stack of actors in ClutterStage. This stack
is cached, but for now, don't use the cache as much as possible.

The picking routines are still tied to painting.

When projecting the actor vertexes, do it manually and take the modelview
matrix of the framebuffer into account as well.

CPU usage on an Intel i7-7700, tested with two different GPUs/drivers:

  |         |     Intel | Nvidia |
  | ------: | --------: | -----: |
  | Moving the mouse:            |
  | Before  |       10% |    10% |
  | After   |        6% |     6% |
  | Moving a window:             |
  | Before  |       23% |    81% |
  | After   |       19% |    40% |

Closes: https://gitlab.gnome.org/GNOME/mutter/issues/154,
        https://gitlab.gnome.org/GNOME/mutter/issues/691

Helps significantly with: https://gitlab.gnome.org/GNOME/mutter/issues/283,
                          https://gitlab.gnome.org/GNOME/mutter/issues/590,
                          https://gitlab.gnome.org/GNOME/mutter/issues/700

v2: Fix code style issues
    Simplify quadrilateral checks
    Remove the 0.5f hack
    Differentiate axis-aligned rectangles

https://gitlab.gnome.org/GNOME/mutter/merge_requests/189

clutter/clutter/clutter-actor-private.h

@@ -297,8 +297,6 @@ const gchar *                   _clutter_actor_get_debug_name
 void                            _clutter_actor_push_clone_paint                         (void);
 void                            _clutter_actor_pop_clone_paint                          (void);
 
-guint32                         _clutter_actor_get_pick_id                              (ClutterActor *self);
-
 void                            _clutter_actor_shader_pre_paint                         (ClutterActor *actor,
                                                                                          gboolean      repeat);
 void                            _clutter_actor_shader_post_paint                        (ClutterActor *actor);

clutter/clutter/clutter-actor.c

@@ -736,8 +736,6 @@ struct _ClutterActorPrivate
 
   gchar *name; /* a non-unique name, used for debugging */
 
-  gint32 pick_id; /* per-stage unique id, used for picking */
-
   /* a back-pointer to the Pango context that we can use
    * to create pre-configured PangoLayout
    */
@@ -1290,6 +1288,106 @@ clutter_actor_verify_map_state (ClutterActor *self)
 
 #endif /* CLUTTER_ENABLE_DEBUG */
 
+static gboolean
+_clutter_actor_transform_local_box_to_stage (ClutterActor          *self,
+                                             ClutterStage          *stage,
+                                             const ClutterActorBox *box,
+                                             ClutterPoint           vertices[4])
+{
+  CoglFramebuffer *fb = cogl_get_draw_framebuffer ();
+  CoglMatrix stage_transform, inv_stage_transform;
+  CoglMatrix modelview, transform_to_stage;
+  int v;
+
+  clutter_actor_get_transform (CLUTTER_ACTOR (stage), &stage_transform);
+  if (!cogl_matrix_get_inverse (&stage_transform, &inv_stage_transform))
+    return FALSE;
+  cogl_framebuffer_get_modelview_matrix (fb, &modelview);
+  cogl_matrix_multiply (&transform_to_stage, &inv_stage_transform, &modelview);
+
+  vertices[0].x = box->x1;
+  vertices[0].y = box->y1;
+
+  vertices[1].x = box->x2;
+  vertices[1].y = box->y1;
+
+  vertices[2].x = box->x2;
+  vertices[2].y = box->y2;
+
+  vertices[3].x = box->x1;
+  vertices[3].y = box->y2;
+
+  for (v = 0; v < 4; v++)
+    {
+      float z = 0.f;
+      float w = 1.f;
+
+      cogl_matrix_transform_point (&transform_to_stage,
+                                   &vertices[v].x,
+                                   &vertices[v].y,
+                                   &z,
+                                   &w);
+    }
+
+  return TRUE;
+}
+
+/**
+ * clutter_actor_pick_box:
+ * @self: The #ClutterActor being "pick" painted.
+ * @box: A rectangle in the actor's own local coordinates.
+ *
+ * Logs (does a virtual paint of) a rectangle for picking. Note that @box is
+ * in the actor's own local coordinates, so is usually {0,0,width,height}
+ * to include the whole actor. That is unless the actor has a shaped input
+ * region in which case you may wish to log the (multiple) smaller rectangles
+ * that make up the input region.
+ */
+void
+clutter_actor_pick_box (ClutterActor          *self,
+                        const ClutterActorBox *box)
+{
+  ClutterStage *stage;
+  ClutterPoint vertices[4];
+
+  g_return_if_fail (CLUTTER_IS_ACTOR (self));
+  g_return_if_fail (box != NULL);
+
+  /* An empty box to a "pick" paint means to paint nothing at all. */
+  if (box->x1 >= box->x2 || box->y1 >= box->y2)
+    return;
+
+  stage = CLUTTER_STAGE (_clutter_actor_get_stage_internal (self));
+
+  if (_clutter_actor_transform_local_box_to_stage (self, stage, box, vertices))
+    _clutter_stage_log_pick (stage, vertices, self);
+}
+
+static gboolean
+_clutter_actor_push_pick_clip (ClutterActor          *self,
+                               const ClutterActorBox *clip)
+{
+  ClutterStage *stage;
+  ClutterPoint vertices[4];
+
+  stage = CLUTTER_STAGE (_clutter_actor_get_stage_internal (self));
+
+  if (!_clutter_actor_transform_local_box_to_stage (self, stage, clip, vertices))
+    return FALSE;
+
+  _clutter_stage_push_pick_clip (stage, vertices);
+  return TRUE;
+}
+
+static void
+_clutter_actor_pop_pick_clip (ClutterActor *self)
+{
+  ClutterActor *stage;
+
+  stage = _clutter_actor_get_stage_internal (self);
+  _clutter_stage_pop_pick_clip (CLUTTER_STAGE (stage));
+}
+
 static void
 clutter_actor_set_mapped (ClutterActor *self,
                           gboolean      mapped)
@@ -1518,8 +1616,7 @@ clutter_actor_update_map_state (ClutterActor  *self,
 static void
 clutter_actor_real_map (ClutterActor *self)
 {
-  ClutterActorPrivate *priv = self->priv;
-  ClutterActor *stage, *iter;
+  ClutterActor *iter;
 
   g_assert (!CLUTTER_ACTOR_IS_MAPPED (self));
 
@@ -1530,13 +1627,6 @@ clutter_actor_real_map (ClutterActor *self)
 
   self->priv->needs_paint_volume_update = TRUE;
 
-  stage = _clutter_actor_get_stage_internal (self);
-  priv->pick_id = _clutter_stage_acquire_pick_id (CLUTTER_STAGE (stage), self);
-
-  CLUTTER_NOTE (ACTOR, "Pick id '%d' for actor '%s'",
-                priv->pick_id,
-                _clutter_actor_get_debug_name (self));
-
   clutter_actor_ensure_resource_scale (self);
 
   /* notify on parent mapped before potentially mapping
@@ -1641,11 +1731,6 @@ clutter_actor_real_unmap (ClutterActor *self)
 
       stage = CLUTTER_STAGE (_clutter_actor_get_stage_internal (self));
 
-      if (stage != NULL)
-        _clutter_stage_release_pick_id (stage, priv->pick_id);
-
-      priv->pick_id = -1;
-
       if (stage != NULL &&
           clutter_stage_get_key_focus (stage) == self)
         {
@@ -2264,46 +2349,16 @@ static void
 clutter_actor_real_pick (ClutterActor       *self,
 			 const ClutterColor *color)
 {
-  CoglFramebuffer *framebuffer = cogl_get_draw_framebuffer ();
-
-  /* the default implementation is just to paint a rectangle
-   * with the same size of the actor using the passed color
-   */
   if (clutter_actor_should_pick_paint (self))
     {
-      static CoglPipeline *default_pick_pipeline = NULL;
-      ClutterActorBox box = { 0, };
-      CoglPipeline *pick_pipeline;
-      float width, height;
+      ClutterActorBox box = {
+        .x1 = 0,
+        .y1 = 0,
+        .x2 = clutter_actor_get_width (self),
+        .y2 = clutter_actor_get_height (self),
+      };
 
-      if (G_UNLIKELY (default_pick_pipeline == NULL))
-        {
-          CoglContext *ctx =
-            clutter_backend_get_cogl_context (clutter_get_default_backend ());
-
-          default_pick_pipeline = cogl_pipeline_new (ctx);
-        }
-
-      g_assert (default_pick_pipeline != NULL);
-      pick_pipeline = cogl_pipeline_copy (default_pick_pipeline);
-
-      clutter_actor_get_allocation_box (self, &box);
-
-      width = box.x2 - box.x1;
-      height = box.y2 - box.y1;
-
-      cogl_pipeline_set_color4ub (pick_pipeline,
-                                  color->red,
-                                  color->green,
-                                  color->blue,
-                                  color->alpha);
-
-      cogl_framebuffer_draw_rectangle (framebuffer,
-                                       pick_pipeline,
-                                       0, 0,
-                                       width, height);
-
-      cogl_object_unref (pick_pipeline);
+      clutter_actor_pick_box (self, &box);
     }
 
   /* XXX - this thoroughly sucks, but we need to maintain compatibility
@@ -3594,15 +3649,6 @@ _clutter_actor_update_last_paint_volume (ClutterActor *self)
   priv->last_paint_volume_valid = TRUE;
 }
 
-guint32
-_clutter_actor_get_pick_id (ClutterActor *self)
-{
-  if (self->priv->pick_id < 0)
-    return 0;
-
-  return self->priv->pick_id;
-}
-
 /* This is the same as clutter_actor_add_effect except that it doesn't
    queue a redraw and it doesn't notify on the effect property */
 static void
@@ -3834,6 +3880,7 @@ clutter_actor_paint (ClutterActor *self)
 {
   ClutterActorPrivate *priv;
   ClutterPickMode pick_mode;
+  ClutterActorBox clip;
   gboolean clip_set = FALSE;
   ClutterStage *stage;
 
@@ -3927,26 +3974,40 @@ clutter_actor_paint (ClutterActor *self)
 
   if (priv->has_clip)
     {
-      CoglFramebuffer *fb = _clutter_stage_get_active_framebuffer (stage);
-      cogl_framebuffer_push_rectangle_clip (fb,
-                                            priv->clip.origin.x,
-                                            priv->clip.origin.y,
-                                            priv->clip.origin.x + priv->clip.size.width,
-                                            priv->clip.origin.y + priv->clip.size.height);
+      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)
     {
-      CoglFramebuffer *fb = _clutter_stage_get_active_framebuffer (stage);
-      gfloat width, height;
-
-      width  = priv->allocation.x2 - priv->allocation.x1;
-      height = priv->allocation.y2 - priv->allocation.y1;
-
-      cogl_framebuffer_push_rectangle_clip (fb, 0, 0, width, height);
+      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)
+    {
+      if (pick_mode == CLUTTER_PICK_NONE)
+        {
+          CoglFramebuffer *fb = _clutter_stage_get_active_framebuffer (stage);
+
+          cogl_framebuffer_push_rectangle_clip (fb,
+                                                clip.x1,
+                                                clip.y1,
+                                                clip.x2,
+                                                clip.y2);
+        }
+      else
+        {
+          if (!_clutter_actor_push_pick_clip (self, &clip))
+            clip_set = FALSE;
+        }
+    }
+
   if (pick_mode == CLUTTER_PICK_NONE)
     {
       /* We check whether we need to add the flatten effect before
@@ -4025,9 +4086,16 @@ clutter_actor_paint (ClutterActor *self)
 done:
   if (clip_set)
     {
-      CoglFramebuffer *fb = _clutter_stage_get_active_framebuffer (stage);
+      if (pick_mode == CLUTTER_PICK_NONE)
+        {
+          CoglFramebuffer *fb = _clutter_stage_get_active_framebuffer (stage);
 
-      cogl_framebuffer_pop_clip (fb);
+          cogl_framebuffer_pop_clip (fb);
+        }
+      else
+        {
+          _clutter_actor_pop_pick_clip (self);
+        }
     }
 
   cogl_pop_matrix ();
@@ -4098,11 +4166,12 @@ clutter_actor_continue_paint (ClutterActor *self)
         {
           ClutterColor col = { 0, };
 
-          _clutter_id_to_color (_clutter_actor_get_pick_id (self), &col);
-
-          /* Actor will then paint silhouette of itself in supplied
-           * color.  See clutter_stage_get_actor_at_pos() for where
-           * picking is enabled.
+          /* The actor will log a silhouette of itself to the stage pick log.
+           * Note that the picking color is no longer used as the "log" instead
+           * keeps a weak pointer to the actor itself. But we keep the color
+           * parameter for now so as to maintain ABI compatibility. The color
+           * parameter can be removed when someone feels like breaking the ABI
+           * along with gnome-shell.
            *
            * XXX:2.0 - Call the pick() virtual directly
            */
@@ -8651,8 +8720,6 @@ clutter_actor_init (ClutterActor *self)
 
   self->priv = priv = clutter_actor_get_instance_private (self);
 
-  priv->pick_id = -1;
-
   priv->opacity = 0xff;
   priv->show_on_set_parent = TRUE;
   priv->resource_scale = -1.0f;

clutter/clutter/clutter-actor.h

@@ -902,6 +902,10 @@ void                            clutter_actor_bind_model_with_properties
                                                                                  const char                 *first_model_property,
                                                                                  ...);
 
+CLUTTER_EXPORT
+void clutter_actor_pick_box (ClutterActor          *self,
+                             const ClutterActorBox *box);
+
 G_END_DECLS
 
 #endif /* __CLUTTER_ACTOR_H__ */

clutter/clutter/clutter-base-types.c

@@ -570,6 +570,68 @@ G_DEFINE_BOXED_TYPE_WITH_CODE (ClutterPoint, clutter_point,
                                clutter_point_free,
                                CLUTTER_REGISTER_INTERVAL_PROGRESS (clutter_point_progress))
 
+static int
+clutter_point_compare_line (const ClutterPoint *p,
+                            const ClutterPoint *a,
+                            const ClutterPoint *b)
+{
+  float x1 = b->x - a->x;
+  float y1 = b->y - a->y;
+  float x2 = p->x - a->x;
+  float y2 = p->y - a->y;
+  float cross_z = x1 * y2 - y1 * x2;
+
+  if (cross_z > 0.f)
+    return 1;
+  else if (cross_z < 0.f)
+    return -1;
+  else
+    return 0;
+}
+
+/**
+ * clutter_point_inside_quadrilateral:
+ * @point: a #ClutterPoint to test
+ * @vertices: array of vertices of the quadrilateral, in clockwise order,
+ *            from top-left to bottom-left
+ *
+ * Determines whether a point is inside the convex quadrilateral provided,
+ * and not on any of its edges or vertices.
+ *
+ * Returns: %TRUE if @point is inside the quadrilateral
+ */
+gboolean
+clutter_point_inside_quadrilateral (const ClutterPoint *point,
+                                    const ClutterPoint *vertices)
+{
+  unsigned int i;
+  int first_side;
+
+  first_side = 0;
+
+  for (i = 0; i < 4; i++)
+    {
+      int side;
+
+      side = clutter_point_compare_line (point,
+                                         &vertices[i],
+                                         &vertices[(i + 1) % 4]);
+
+      if (side)
+        {
+          if (first_side == 0)
+            first_side = side;
+          else if (side != first_side)
+            return FALSE;
+        }
+    }
+
+  if (first_side == 0)
+    return FALSE;
+
+  return TRUE;
+}
+
 
 
 /*

clutter/clutter/clutter-debug.h

@@ -30,7 +30,6 @@ typedef enum
 typedef enum
 {
   CLUTTER_DEBUG_NOP_PICKING         = 1 << 0,
-  CLUTTER_DEBUG_DUMP_PICK_BUFFERS   = 1 << 1
 } ClutterPickDebugFlag;
 
 typedef enum

clutter/clutter/clutter-main.c

@@ -129,7 +129,6 @@ static const GDebugKey clutter_debug_keys[] = {
 
 static const GDebugKey clutter_pick_debug_keys[] = {
   { "nop-picking", CLUTTER_DEBUG_NOP_PICKING },
-  { "dump-pick-buffers", CLUTTER_DEBUG_DUMP_PICK_BUFFERS },
 };
 
 static const GDebugKey clutter_paint_debug_keys[] = {
@@ -401,125 +400,6 @@ clutter_disable_accessibility (void)
   clutter_enable_accessibility = FALSE;
 }
 
-void
-_clutter_id_to_color (guint         id_,
-                      ClutterColor *col)
-{
-  ClutterMainContext *ctx;
-  gint red, green, blue;
-
-  ctx = _clutter_context_get_default ();
-
-  if (ctx->fb_g_mask == 0)
-    {
-      /* Figure out framebuffer masks used for pick */
-      cogl_get_bitmasks (&ctx->fb_r_mask,
-			 &ctx->fb_g_mask,
-			 &ctx->fb_b_mask, NULL);
-
-      ctx->fb_r_mask_used = ctx->fb_r_mask;
-      ctx->fb_g_mask_used = ctx->fb_g_mask;
-      ctx->fb_b_mask_used = ctx->fb_b_mask;
-
-      /* XXX - describe what "fuzzy picking" is */
-      if (clutter_use_fuzzy_picking)
-	{
-	  ctx->fb_r_mask_used--;
-	  ctx->fb_g_mask_used--;
-	  ctx->fb_b_mask_used--;
-	}
-    }
-
-  /* compute the numbers we'll store in the components */
-  red   = (id_ >> (ctx->fb_g_mask_used+ctx->fb_b_mask_used))
-        & (0xff >> (8-ctx->fb_r_mask_used));
-  green = (id_ >> ctx->fb_b_mask_used)
-        & (0xff >> (8-ctx->fb_g_mask_used));
-  blue  = (id_)
-        & (0xff >> (8-ctx->fb_b_mask_used));
-
-  /* shift left bits a bit and add one, this circumvents
-   * at least some potential rounding errors in GL/GLES
-   * driver / hw implementation.
-   */
-  if (ctx->fb_r_mask_used != ctx->fb_r_mask)
-    red = red * 2;
-  if (ctx->fb_g_mask_used != ctx->fb_g_mask)
-    green = green * 2;
-  if (ctx->fb_b_mask_used != ctx->fb_b_mask)
-    blue  = blue  * 2;
-
-  /* shift up to be full 8bit values */
-  red   = (red   << (8 - ctx->fb_r_mask)) | (0x7f >> (ctx->fb_r_mask_used));
-  green = (green << (8 - ctx->fb_g_mask)) | (0x7f >> (ctx->fb_g_mask_used));
-  blue  = (blue  << (8 - ctx->fb_b_mask)) | (0x7f >> (ctx->fb_b_mask_used));
-
-  col->red   = red;
-  col->green = green;
-  col->blue  = blue;
-  col->alpha = 0xff;
-
-  /* XXX: We rotate the nibbles of the colors here so that there is a
-   * visible variation between colors of sequential actor identifiers;
-   * otherwise pick buffers dumped to an image will pretty much just look
-   * black.
-   */
-  if (G_UNLIKELY (clutter_pick_debug_flags & CLUTTER_DEBUG_DUMP_PICK_BUFFERS))
-    {
-      col->red   = (col->red << 4)   | (col->red >> 4);
-      col->green = (col->green << 4) | (col->green >> 4);
-      col->blue  = (col->blue << 4)  | (col->blue >> 4);
-    }
-}
-
-guint
-_clutter_pixel_to_id (guchar pixel[4])
-{
-  ClutterMainContext *ctx;
-  gint red, green, blue;
-  guint retval;
-
-  ctx = _clutter_context_get_default ();
-
-  /* reduce the pixel components to the number of bits actually used of the
-   * 8bits.
-   */
-  if (G_UNLIKELY (clutter_pick_debug_flags & CLUTTER_DEBUG_DUMP_PICK_BUFFERS))
-    {
-      guchar tmp;
-
-      /* XXX: In _clutter_id_to_color we rotated the nibbles of the colors so
-       * that there is a visible variation between colors of sequential actor
-       * identifiers (otherwise pick buffers dumped to an image will pretty
-       * much just look black.) Here we reverse that rotation.
-       */
-      tmp = ((pixel[0] << 4) | (pixel[0] >> 4));
-      red = tmp >> (8 - ctx->fb_r_mask);
-      tmp = ((pixel[1] << 4) | (pixel[1] >> 4));
-      green = tmp >> (8 - ctx->fb_g_mask);
-      tmp = ((pixel[2] << 4) | (pixel[2] >> 4));
-      blue = tmp >> (8 - ctx->fb_b_mask);
-    }
-  else
-    {
-      red   = pixel[0] >> (8 - ctx->fb_r_mask);
-      green = pixel[1] >> (8 - ctx->fb_g_mask);
-      blue  = pixel[2] >> (8 - ctx->fb_b_mask);
-    }
-
-  /* divide potentially by two if 'fuzzy' */
-  red   = red   >> (ctx->fb_r_mask - ctx->fb_r_mask_used);
-  green = green >> (ctx->fb_g_mask - ctx->fb_g_mask_used);
-  blue  = blue  >> (ctx->fb_b_mask - ctx->fb_b_mask_used);
-
-  /* combine the correct per component values into the final id */
-  retval = blue
-         + (green <<  ctx->fb_b_mask_used)
-         + (red << (ctx->fb_b_mask_used + ctx->fb_g_mask_used));
-
-  return retval;
-}
-
 static CoglPangoFontMap *
 clutter_context_get_pango_fontmap (void)
 {

clutter/clutter/clutter-private.h

@@ -199,11 +199,6 @@ gboolean      _clutter_feature_init (GError **error);
 gboolean        _clutter_diagnostic_enabled     (void);
 void            _clutter_diagnostic_message     (const char *fmt, ...) G_GNUC_PRINTF (1, 2);
 
-/* Picking code */
-guint           _clutter_pixel_to_id            (guchar        pixel[4]);
-void            _clutter_id_to_color            (guint         id,
-                                                 ClutterColor *col);
-
 CLUTTER_EXPORT
 void            _clutter_set_sync_to_vblank     (gboolean      sync_to_vblank);
 

clutter/clutter/clutter-stage-private.h

@@ -79,6 +79,15 @@ gint64    _clutter_stage_get_update_time                  (ClutterStage *stage);
 void     _clutter_stage_clear_update_time                 (ClutterStage *stage);
 gboolean _clutter_stage_has_full_redraw_queued            (ClutterStage *stage);
 
+void _clutter_stage_log_pick (ClutterStage       *stage,
+                              const ClutterPoint *vertices,
+                              ClutterActor       *actor);
+
+void _clutter_stage_push_pick_clip (ClutterStage       *stage,
+                                    const ClutterPoint *vertices);
+
+void _clutter_stage_pop_pick_clip (ClutterStage *stage);
+
 ClutterActor *_clutter_stage_do_pick (ClutterStage    *stage,
                                       gint             x,
                                       gint             y,
@@ -97,13 +106,6 @@ void                          _clutter_stage_queue_redraw_entry_invalidate (Clut
 
 CoglFramebuffer *_clutter_stage_get_active_framebuffer (ClutterStage *stage);
 
-gint32          _clutter_stage_acquire_pick_id          (ClutterStage *stage,
-                                                         ClutterActor *actor);
-void            _clutter_stage_release_pick_id          (ClutterStage *stage,
-                                                         gint32        pick_id);
-ClutterActor *  _clutter_stage_get_actor_by_pick_id     (ClutterStage *stage,
-                                                         gint32        pick_id);
-
 void            _clutter_stage_add_pointer_drag_actor    (ClutterStage       *stage,
                                                           ClutterInputDevice *device,
                                                           ClutterActor       *actor);

clutter/clutter/clutter-stage-window.c

@@ -275,24 +275,6 @@ _clutter_stage_window_redraw (ClutterStageWindow *window)
     iface->redraw (window);
 }
 
-
-void
-_clutter_stage_window_get_dirty_pixel (ClutterStageWindow *window,
-                                       ClutterStageView   *view,
-                                       int *x, int *y)
-{
-  ClutterStageWindowInterface *iface;
-
-  *x = 0;
-  *y = 0;
-
-  g_return_if_fail (CLUTTER_IS_STAGE_WINDOW (window));
-
-  iface = CLUTTER_STAGE_WINDOW_GET_IFACE (window);
-  if (iface->get_dirty_pixel)
-    iface->get_dirty_pixel (window, view, x, y);
-}
-
 gboolean
 _clutter_stage_window_can_clip_redraws (ClutterStageWindow *window)
 {

clutter/clutter/clutter-stage-window.h

@@ -64,10 +64,6 @@ struct _ClutterStageWindowInterface
 
   void              (* redraw)                  (ClutterStageWindow *stage_window);
 
-  void              (* get_dirty_pixel)         (ClutterStageWindow *stage_window,
-                                                 ClutterStageView   *view,
-                                                 int *x, int *y);
-
   gboolean          (* can_clip_redraws)        (ClutterStageWindow *stage_window);
 
   GList            *(* get_views)               (ClutterStageWindow *stage_window);
@@ -112,10 +108,6 @@ void              _clutter_stage_window_set_accept_focus        (ClutterStageWin
 
 void              _clutter_stage_window_redraw                  (ClutterStageWindow *window);
 
-void              _clutter_stage_window_get_dirty_pixel         (ClutterStageWindow *window,
-                                                                 ClutterStageView   *view,
-                                                                 int *x, int *y);
-
 gboolean          _clutter_stage_window_can_clip_redraws        (ClutterStageWindow *window);
 
 GList *           _clutter_stage_window_get_views               (ClutterStageWindow *window);

clutter/clutter/clutter-stage.c

@@ -105,6 +105,19 @@ struct _ClutterStageQueueRedrawEntry
   ClutterPaintVolume clip;
 };
 
+typedef struct _PickRecord
+{
+  ClutterPoint vertex[4];
+  ClutterActor *actor;
+  int clip_stack_top;
+} PickRecord;
+
+typedef struct _PickClipRecord
+{
+  int prev;
+  ClutterPoint vertex[4];
+} PickClipRecord;
+
 struct _ClutterStagePrivate
 {
   /* the stage implementation */
@@ -138,7 +151,11 @@ struct _ClutterStagePrivate
   GTimer *fps_timer;
   gint32 timer_n_frames;
 
-  ClutterIDPool *pick_id_pool;
+  GArray *pick_stack;
+  GArray *pick_clip_stack;
+  int pick_clip_stack_top;
+  gboolean pick_stack_frozen;
+  ClutterPickMode cached_pick_mode;
 
 #ifdef CLUTTER_ENABLE_DEBUG
   gulong redraw_count;
@@ -323,6 +340,214 @@ clutter_stage_get_preferred_height (ClutterActor *self,
     *natural_height_p = geom.height;
 }
 
+/* In order to keep weak pointers valid between frames we need them to not
+ * move in memory, so the stack is marked as "frozen".
+ */
+static void
+_clutter_stage_freeze_pick_stack (ClutterStage *stage)
+{
+  ClutterStagePrivate *priv = stage->priv;
+  int i;
+
+  if (priv->pick_stack_frozen)
+    return;
+
+  for (i = 0; i < priv->pick_stack->len; i++)
+    {
+      PickRecord *rec = &g_array_index (priv->pick_stack, PickRecord, i);
+
+      if (rec->actor)
+        g_object_add_weak_pointer (G_OBJECT (rec->actor),
+                                   (gpointer) &rec->actor);
+    }
+
+  priv->pick_stack_frozen = TRUE;
+}
+
+static void
+_clutter_stage_thaw_pick_stack (ClutterStage *stage)
+{
+  ClutterStagePrivate *priv = stage->priv;
+  int i;
+
+  if (!priv->pick_stack_frozen)
+    return;
+
+  for (i = 0; i < priv->pick_stack->len; i++)
+    {
+      PickRecord *rec = &g_array_index (priv->pick_stack, PickRecord, i);
+
+      if (rec->actor)
+        g_object_remove_weak_pointer (G_OBJECT (rec->actor),
+                                      (gpointer) &rec->actor);
+    }
+
+  priv->pick_stack_frozen = FALSE;
+}
+
+static void
+_clutter_stage_clear_pick_stack (ClutterStage *stage)
+{
+  ClutterStagePrivate *priv = stage->priv;
+
+  _clutter_stage_thaw_pick_stack (stage);
+  g_array_set_size (priv->pick_stack, 0);
+  g_array_set_size (priv->pick_clip_stack, 0);
+  priv->pick_clip_stack_top = -1;
+  priv->cached_pick_mode = CLUTTER_PICK_NONE;
+}
+
+void
+_clutter_stage_log_pick (ClutterStage       *stage,
+                         const ClutterPoint *vertices,
+                         ClutterActor       *actor)
+{
+  ClutterStagePrivate *priv;
+  PickRecord rec;
+
+  g_return_if_fail (CLUTTER_IS_STAGE (stage));
+  g_return_if_fail (actor != NULL);
+
+  priv = stage->priv;
+
+  g_assert (!priv->pick_stack_frozen);
+
+  memcpy (rec.vertex, vertices, 4 * sizeof (ClutterPoint));
+  rec.actor = actor;
+  rec.clip_stack_top = priv->pick_clip_stack_top;
+
+  g_array_append_val (priv->pick_stack, rec);
+}
+
+void
+_clutter_stage_push_pick_clip (ClutterStage       *stage,
+                               const ClutterPoint *vertices)
+{
+  ClutterStagePrivate *priv;
+  PickClipRecord clip;
+
+  g_return_if_fail (CLUTTER_IS_STAGE (stage));
+
+  priv = stage->priv;
+
+  g_assert (!priv->pick_stack_frozen);
+
+  clip.prev = priv->pick_clip_stack_top;
+  memcpy (clip.vertex, vertices, 4 * sizeof (ClutterPoint));
+
+  g_array_append_val (priv->pick_clip_stack, clip);
+  priv->pick_clip_stack_top = priv->pick_clip_stack->len - 1;
+}
+
+void
+_clutter_stage_pop_pick_clip (ClutterStage *stage)
+{
+  ClutterStagePrivate *priv;
+  const PickClipRecord *top;
+
+  g_return_if_fail (CLUTTER_IS_STAGE (stage));
+
+  priv = stage->priv;
+
+  g_assert (!priv->pick_stack_frozen);
+  g_assert (priv->pick_clip_stack_top >= 0);
+
+  /* Individual elements of pick_clip_stack are not freed. This is so they
+   * can be shared as part of a tree of different stacks used by different
+   * actors in the pick_stack. The whole pick_clip_stack does however get
+   * freed later in _clutter_stage_clear_pick_stack.
+   */
+
+  top = &g_array_index (priv->pick_clip_stack,
+                        PickClipRecord,
+                        priv->pick_clip_stack_top);
+
+  priv->pick_clip_stack_top = top->prev;
+}
+
+static gboolean
+is_quadrilateral_axis_aligned_rectangle (const ClutterPoint *vertices)
+{
+  int i;
+
+  for (i = 0; i < 4; i++)
+    {
+      if (!G_APPROX_VALUE (vertices[i].x,
+                           vertices[(i + 1) % 4].x,
+                           FLT_EPSILON) &&
+          !G_APPROX_VALUE (vertices[i].y,
+                           vertices[(i + 1) % 4].y,
+                           FLT_EPSILON))
+        return FALSE;
+    }
+  return TRUE;
+}
+
+static gboolean
+is_inside_axis_aligned_rectangle (const ClutterPoint *point,
+                                  const ClutterPoint *vertices)
+{
+  float min_x = FLT_MAX;
+  float max_x = FLT_MIN;
+  float min_y = FLT_MAX;
+  float max_y = FLT_MIN;
+  int i;
+
+  for (i = 0; i < 3; i++)
+    {
+      min_x = MIN (min_x, vertices[i].x);
+      min_y = MIN (min_y, vertices[i].y);
+      max_x = MAX (max_x, vertices[i].x);
+      max_y = MAX (max_y, vertices[i].y);
+    }
+
+  return (point->x >= min_x &&
+          point->y >= min_y &&
+          point->x < max_x &&
+          point->y < max_y);
+}
+
+static gboolean
+is_inside_input_region (const ClutterPoint *point,
+                        const ClutterPoint *vertices)
+{
+
+  if (is_quadrilateral_axis_aligned_rectangle (vertices))
+    return is_inside_axis_aligned_rectangle (point, vertices);
+  else
+    return clutter_point_inside_quadrilateral (point, vertices);
+}
+
+static gboolean
+pick_record_contains_pixel (ClutterStage       *stage,
+                            const PickRecord   *rec,
+                            int                 x,
+                            int                 y)
+{
+  const ClutterPoint point = { x, y };
+  ClutterStagePrivate *priv;
+  int clip_index;
+
+  if (!is_inside_input_region (&point, rec->vertex))
+      return FALSE;
+
+  priv = stage->priv;
+  clip_index = rec->clip_stack_top;
+  while (clip_index >= 0)
+    {
+      const PickClipRecord *clip = &g_array_index (priv->pick_clip_stack,
+                                                   PickClipRecord,
+                                                   clip_index);
+
+      if (!is_inside_input_region (&point, clip->vertex))
+        return FALSE;
+
+      clip_index = clip->prev;
+    }
+
+  return TRUE;
+}
+
 static inline void
 queue_full_redraw (ClutterStage *stage)
 {
@@ -630,6 +855,12 @@ clutter_stage_do_paint_view (ClutterStage                *stage,
   float viewport[4];
   cairo_rectangle_int_t geom;
 
+  /* Any mode of painting/picking invalidates the pick cache, unless we're
+   * in the middle of building it. So we reset the cached flag but don't
+   * completely clear the pick stack.
+   */
+  priv->cached_pick_mode = CLUTTER_PICK_NONE;
+
   _clutter_stage_window_get_geometry (priv->impl, &geom);
 
   viewport[0] = priv->viewport[0];
@@ -1398,40 +1629,6 @@ clutter_stage_get_redraw_clip_bounds (ClutterStage          *stage,
     }
 }
 
-static void
-read_pixels_to_file (CoglFramebuffer *fb,
-                     char            *filename_stem,
-                     int              x,
-                     int              y,
-                     int              width,
-                     int              height)
-{
-  guint8 *data;
-  cairo_surface_t *surface;
-  static int read_count = 0;
-  char *filename = g_strdup_printf ("%s-%05d.png",
-                                    filename_stem,
-                                    read_count);
-
-  data = g_malloc (4 * width * height);
-  cogl_framebuffer_read_pixels (fb,
-                                x, y, width, height,
-                                CLUTTER_CAIRO_FORMAT_ARGB32,
-                                data);
-
-  surface = cairo_image_surface_create_for_data (data, CAIRO_FORMAT_RGB24,
-                                                 width, height,
-                                                 width * 4);
-
-  cairo_surface_write_to_png (surface, filename);
-  cairo_surface_destroy (surface);
-
-  g_free (data);
-  g_free (filename);
-
-  read_count++;
-}
-
 static ClutterActor *
 _clutter_stage_do_pick_on_view (ClutterStage     *stage,
                                 gint              x,
@@ -1439,140 +1636,42 @@ _clutter_stage_do_pick_on_view (ClutterStage     *stage,
                                 ClutterPickMode   mode,
                                 ClutterStageView *view)
 {
-  ClutterActor *actor = CLUTTER_ACTOR (stage);
+  ClutterMainContext *context = _clutter_context_get_default ();
   ClutterStagePrivate *priv = stage->priv;
   CoglFramebuffer *fb = clutter_stage_view_get_framebuffer (view);
-  cairo_rectangle_int_t view_layout;
-  ClutterMainContext *context;
-  guchar pixel[4] = { 0xff, 0xff, 0xff, 0xff };
-  CoglColor stage_pick_id;
-  gboolean dither_enabled_save;
-  ClutterActor *retval;
-  gint dirty_x;
-  gint dirty_y;
-  gint read_x;
-  gint read_y;
-  float fb_width, fb_height;
-  float fb_scale;
-  float viewport_offset_x;
-  float viewport_offset_y;
+  int i;
 
-  priv = stage->priv;
+  g_assert (context->pick_mode == CLUTTER_PICK_NONE);
 
-  context = _clutter_context_get_default ();
-  fb_scale = clutter_stage_view_get_scale (view);
-  clutter_stage_view_get_layout (view, &view_layout);
-
-  fb_width = view_layout.width * fb_scale;
-  fb_height = view_layout.height * fb_scale;
-  cogl_push_framebuffer (fb);
-
-  /* needed for when a context switch happens */
-  _clutter_stage_maybe_setup_viewport (stage, view);
-
-  /* FIXME: For some reason leaving the cogl clip stack empty causes the
-   * picking to not work at all, so setting it the whole framebuffer content
-   * for now. */
-  cogl_framebuffer_push_scissor_clip (fb, 0, 0,
-                                      view_layout.width * fb_scale,
-                                      view_layout.height * fb_scale);
-
-  _clutter_stage_window_get_dirty_pixel (priv->impl, view, &dirty_x, &dirty_y);
-
-  if (G_LIKELY (!(clutter_pick_debug_flags & CLUTTER_DEBUG_DUMP_PICK_BUFFERS)))
+  if (mode != priv->cached_pick_mode)
     {
-      CLUTTER_NOTE (PICK, "Pushing pick scissor clip x: %d, y: %d, 1x1",
-                    (int) (dirty_x * fb_scale),
-                    (int) (dirty_y * fb_scale));
-      cogl_framebuffer_push_scissor_clip (fb, dirty_x * fb_scale, dirty_y * fb_scale, 1, 1);
+      _clutter_stage_clear_pick_stack (stage);
+
+      cogl_push_framebuffer (fb);
+
+      context->pick_mode = mode;
+      clutter_stage_do_paint_view (stage, view, NULL);
+      context->pick_mode = CLUTTER_PICK_NONE;
+      priv->cached_pick_mode = mode;
+
+      cogl_pop_framebuffer ();
+
+      _clutter_stage_freeze_pick_stack (stage);
     }
 
-  viewport_offset_x = x * fb_scale - dirty_x * fb_scale;
-  viewport_offset_y = y * fb_scale - dirty_y * fb_scale;
-  CLUTTER_NOTE (PICK, "Setting viewport to %f, %f, %f, %f",
-                priv->viewport[0] * fb_scale - viewport_offset_x,
-                priv->viewport[1] * fb_scale - viewport_offset_y,
-                priv->viewport[2] * fb_scale,
-                priv->viewport[3] * fb_scale);
-  cogl_framebuffer_set_viewport (fb,
-                                 priv->viewport[0] * fb_scale - viewport_offset_x,
-                                 priv->viewport[1] * fb_scale - viewport_offset_y,
-                                 priv->viewport[2] * fb_scale,
-                                 priv->viewport[3] * fb_scale);
-
-  read_x = dirty_x * fb_scale;
-  read_y = dirty_y * fb_scale;
-
-  CLUTTER_NOTE (PICK, "Performing pick at %i,%i on view %dx%d+%d+%d s: %f",
-                x, y,
-                view_layout.width, view_layout.height,
-                view_layout.x, view_layout.y, fb_scale);
-
-  cogl_color_init_from_4ub (&stage_pick_id, 255, 255, 255, 255);
-  cogl_framebuffer_clear (fb, COGL_BUFFER_BIT_COLOR | COGL_BUFFER_BIT_DEPTH, &stage_pick_id);
-
-  /* Disable dithering (if any) when doing the painting in pick mode */
-  dither_enabled_save = cogl_framebuffer_get_dither_enabled (fb);
-  cogl_framebuffer_set_dither_enabled (fb, FALSE);
-
-  /* Render the entire scence in pick mode - just single colored silhouette's
-   * are drawn offscreen (as we never swap buffers)
-  */
-  context->pick_mode = mode;
-
-  clutter_stage_do_paint_view (stage, view, NULL);
-  context->pick_mode = CLUTTER_PICK_NONE;
-
-  /* Read the color of the screen co-ords pixel. RGBA_8888_PRE is used
-     even though we don't care about the alpha component because under
-     GLES this is the only format that is guaranteed to work so Cogl
-     will end up having to do a conversion if any other format is
-     used. The format is requested as pre-multiplied because Cogl
-     assumes that all pixels in the framebuffer are premultiplied so
-     it avoids a conversion. */
-  cogl_framebuffer_read_pixels (fb,
-                                read_x, read_y, 1, 1,
-                                COGL_PIXEL_FORMAT_RGBA_8888_PRE,
-                                pixel);
-
-  if (G_UNLIKELY (clutter_pick_debug_flags & CLUTTER_DEBUG_DUMP_PICK_BUFFERS))
+  /* Search all "painted" pickable actors from front to back. A linear search
+   * is required, and also performs fine since there is typically only
+   * on the order of dozens of actors in the list (on screen) at a time.
+   */
+  for (i = priv->pick_stack->len - 1; i >= 0; i--)
     {
-      char *file_name =
-        g_strdup_printf ("pick-buffer-%s-view-x-%d",
-                         _clutter_actor_get_debug_name (actor),
-                         view_layout.x);
+      const PickRecord *rec = &g_array_index (priv->pick_stack, PickRecord, i);
 
-      read_pixels_to_file (fb, file_name, 0, 0, fb_width, fb_height);
-
-      g_free (file_name);
+      if (rec->actor && pick_record_contains_pixel (stage, rec, x, y))
+        return rec->actor;
     }
 
-  /* Restore whether GL_DITHER was enabled */
-  cogl_framebuffer_set_dither_enabled (fb, dither_enabled_save);
-
-  if (G_LIKELY (!(clutter_pick_debug_flags & CLUTTER_DEBUG_DUMP_PICK_BUFFERS)))
-    cogl_framebuffer_pop_clip (fb);
-
-  cogl_framebuffer_pop_clip (fb);
-
-  _clutter_stage_dirty_viewport (stage);
-
-  if (pixel[0] == 0xff && pixel[1] == 0xff && pixel[2] == 0xff)
-    retval = actor;
-  else
-    {
-      guint32 id_ = _clutter_pixel_to_id (pixel);
-
-      retval = _clutter_stage_get_actor_by_pick_id (stage, id_);
-      CLUTTER_NOTE (PICK, "Picking actor %s with id %u (pixel: 0x%x%x%x%x",
-                    G_OBJECT_TYPE_NAME (retval),
-                    id_,
-                    pixel[0], pixel[1], pixel[2], pixel[3]);
-    }
-
-  cogl_pop_framebuffer ();
-
-  return retval;
+  return CLUTTER_ACTOR (stage);
 }
 
 /**
@@ -1867,7 +1966,9 @@ clutter_stage_finalize (GObject *object)
 
   g_array_free (priv->paint_volume_stack, TRUE);
 
-  _clutter_id_pool_free (priv->pick_id_pool);
+  _clutter_stage_clear_pick_stack (stage);
+  g_array_free (priv->pick_clip_stack, TRUE);
+  g_array_free (priv->pick_stack, TRUE);
 
   if (priv->fps_timer != NULL)
     g_timer_destroy (priv->fps_timer);
@@ -2302,7 +2403,10 @@ clutter_stage_init (ClutterStage *self)
   priv->paint_volume_stack =
     g_array_new (FALSE, FALSE, sizeof (ClutterPaintVolume));
 
-  priv->pick_id_pool = _clutter_id_pool_new (256);
+  priv->pick_stack = g_array_new (FALSE, FALSE, sizeof (PickRecord));
+  priv->pick_clip_stack = g_array_new (FALSE, FALSE, sizeof (PickClipRecord));
+  priv->pick_clip_stack_top = -1;
+  priv->cached_pick_mode = CLUTTER_PICK_NONE;
 }
 
 /**
@@ -3980,6 +4084,12 @@ _clutter_stage_queue_actor_redraw (ClutterStage                 *stage,
   CLUTTER_NOTE (CLIPPING, "stage_queue_actor_redraw (actor=%s, clip=%p): ",
                 _clutter_actor_get_debug_name (actor), clip);
 
+  /* Queuing a redraw or clip change invalidates the pick cache, unless we're
+   * in the middle of building it. So we reset the cached flag but don't
+   * completely clear the pick stack...
+   */
+  priv->cached_pick_mode = CLUTTER_PICK_NONE;
+
   if (!priv->redraw_pending)
     {
       ClutterMasterClock *master_clock;
@@ -4240,39 +4350,6 @@ _clutter_stage_get_active_framebuffer (ClutterStage *stage)
   return stage->priv->active_framebuffer;
 }
 
-gint32
-_clutter_stage_acquire_pick_id (ClutterStage *stage,
-                                ClutterActor *actor)
-{
-  ClutterStagePrivate *priv = stage->priv;
-
-  g_assert (priv->pick_id_pool != NULL);
-
-  return _clutter_id_pool_add (priv->pick_id_pool, actor);
-}
-
-void
-_clutter_stage_release_pick_id (ClutterStage *stage,
-                                gint32        pick_id)
-{
-  ClutterStagePrivate *priv = stage->priv;
-
-  g_assert (priv->pick_id_pool != NULL);
-
-  _clutter_id_pool_remove (priv->pick_id_pool, pick_id);
-}
-
-ClutterActor *
-_clutter_stage_get_actor_by_pick_id (ClutterStage *stage,
-                                     gint32        pick_id)
-{
-  ClutterStagePrivate *priv = stage->priv;
-
-  g_assert (priv->pick_id_pool != NULL);
-
-  return _clutter_id_pool_lookup (priv->pick_id_pool, pick_id);
-}
-
 void
 _clutter_stage_add_pointer_drag_actor (ClutterStage       *stage,
                                        ClutterInputDevice *device,

clutter/clutter/clutter-types.h

@@ -200,6 +200,9 @@ float                   clutter_point_distance  (const ClutterPoint *a,
                                                  const ClutterPoint *b,
                                                  float              *x_distance,
                                                  float              *y_distance);
+CLUTTER_EXPORT
+gboolean clutter_point_inside_quadrilateral     (const ClutterPoint *point,
+                                                 const ClutterPoint *vertices);
 
 /**
  * ClutterSize:

clutter/clutter/cogl/clutter-stage-cogl.c

@@ -1004,55 +1004,6 @@ clutter_stage_cogl_redraw (ClutterStageWindow *stage_window)
   COGL_TRACE_END (ClutterStageCoglRedraw);
 }
 
-static void
-clutter_stage_cogl_get_dirty_pixel (ClutterStageWindow *stage_window,
-                                    ClutterStageView   *view,
-                                    int                *x,
-                                    int                *y)
-{
-  CoglFramebuffer *framebuffer = clutter_stage_view_get_framebuffer (view);
-  gboolean has_buffer_age =
-    cogl_is_onscreen (framebuffer) &&
-    is_buffer_age_enabled ();
-  float fb_scale;
-  gboolean scale_is_fractional;
-
-  fb_scale = clutter_stage_view_get_scale (view);
-  if (fb_scale != floorf (fb_scale))
-    scale_is_fractional = TRUE;
-  else
-    scale_is_fractional = FALSE;
-
-  /*
-   * Buffer damage is tracked in the framebuffer coordinate space
-   * using the damage history. When fractional scaling is used, a
-   * coordinate on the stage might not correspond to the exact position of any
-   * physical pixel, which causes issues when painting using the pick mode.
-   *
-   * For now, always use the (0, 0) pixel for picking when using fractional
-   * framebuffer scaling.
-   */
-  if (!has_buffer_age || scale_is_fractional)
-    {
-      *x = 0;
-      *y = 0;
-    }
-  else
-    {
-      ClutterStageViewCogl *view_cogl = CLUTTER_STAGE_VIEW_COGL (view);
-      ClutterStageViewCoglPrivate *view_priv =
-        clutter_stage_view_cogl_get_instance_private (view_cogl);
-      cairo_rectangle_int_t view_layout;
-      cairo_rectangle_int_t *fb_damage;
-
-      clutter_stage_view_get_layout (view, &view_layout);
-
-      fb_damage = &view_priv->damage_history[DAMAGE_HISTORY (view_priv->damage_index - 1)];
-      *x = fb_damage->x / fb_scale;
-      *y = fb_damage->y / fb_scale;
-    }
-}
-
 static void
 clutter_stage_window_iface_init (ClutterStageWindowInterface *iface)
 {
@@ -1070,7 +1021,6 @@ clutter_stage_window_iface_init (ClutterStageWindowInterface *iface)
   iface->ignoring_redraw_clips = clutter_stage_cogl_ignoring_redraw_clips;
   iface->get_redraw_clip_bounds = clutter_stage_cogl_get_redraw_clip_bounds;
   iface->redraw = clutter_stage_cogl_redraw;
-  iface->get_dirty_pixel = clutter_stage_cogl_get_dirty_pixel;
 }
 
 static void

clutter/clutter/deprecated/clutter-texture.c

@@ -572,83 +572,6 @@ gen_texcoords_and_draw_cogl_rectangle (ClutterActor    *self,
                                             0, 0, t_w, t_h);
 }
 
-static CoglPipeline *
-create_pick_pipeline (ClutterActor *self)
-{
-  ClutterTexture *texture = CLUTTER_TEXTURE (self);
-  ClutterTexturePrivate *priv = texture->priv;
-  CoglPipeline *pick_pipeline = cogl_pipeline_copy (texture_template_pipeline);
-  GError *error = NULL;
-
-  if (!cogl_pipeline_set_layer_combine (pick_pipeline, 0,
-                                        "RGBA = "
-                                        "  MODULATE (CONSTANT, TEXTURE[A])",
-                                        &error))
-    {
-      if (!priv->seen_create_pick_pipeline_warning)
-        g_warning ("Error setting up texture combine for shaped "
-                   "texture picking: %s", error->message);
-      priv->seen_create_pick_pipeline_warning = TRUE;
-      g_error_free (error);
-      cogl_object_unref (pick_pipeline);
-      return NULL;
-    }
-
-  cogl_pipeline_set_blend (pick_pipeline,
-                           "RGBA = ADD (SRC_COLOR[RGBA], 0)",
-                           NULL);
-
-  cogl_pipeline_set_alpha_test_function (pick_pipeline,
-                                         COGL_PIPELINE_ALPHA_FUNC_EQUAL,
-                                         1.0);
-
-  return pick_pipeline;
-}
-
-static void
-clutter_texture_pick (ClutterActor       *self,
-                      const ClutterColor *color)
-{
-  ClutterTexture *texture = CLUTTER_TEXTURE (self);
-  ClutterTexturePrivate *priv = texture->priv;
-  CoglFramebuffer *framebuffer = cogl_get_draw_framebuffer ();
-
-  if (!clutter_actor_should_pick_paint (self))
-    return;
-
-  if (G_LIKELY (priv->pick_with_alpha_supported) && priv->pick_with_alpha)
-    {
-      CoglColor pick_color;
-
-      if (priv->pick_pipeline == NULL)
-        priv->pick_pipeline = create_pick_pipeline (self);
-
-      if (priv->pick_pipeline == NULL)
-        {
-          priv->pick_with_alpha_supported = FALSE;
-          CLUTTER_ACTOR_CLASS (clutter_texture_parent_class)->pick (self,
-                                                                    color);
-          return;
-        }
-
-      if (priv->fbo_handle != NULL)
-        update_fbo (self);
-
-      cogl_color_init_from_4ub (&pick_color,
-                                color->red,
-                                color->green,
-                                color->blue,
-                                0xff);
-      cogl_pipeline_set_layer_combine_constant (priv->pick_pipeline,
-                                                0, &pick_color);
-      cogl_pipeline_set_layer_texture (priv->pick_pipeline, 0,
-                                       clutter_texture_get_cogl_texture (texture));
-      gen_texcoords_and_draw_cogl_rectangle (self, priv->pick_pipeline, framebuffer);
-    }
-  else
-    CLUTTER_ACTOR_CLASS (clutter_texture_parent_class)->pick (self, color);
-}
-
 static void
 clutter_texture_paint (ClutterActor *self)
 {
@@ -767,12 +690,6 @@ clutter_texture_dispose (GObject *object)
       priv->pipeline = NULL;
     }
 
-  if (priv->pick_pipeline != NULL)
-    {
-      cogl_object_unref (priv->pick_pipeline);
-      priv->pick_pipeline = NULL;
-    }
-
   G_OBJECT_CLASS (clutter_texture_parent_class)->dispose (object);
 }
 
@@ -944,7 +861,6 @@ clutter_texture_class_init (ClutterTextureClass *klass)
   GParamSpec *pspec;
 
   actor_class->paint            = clutter_texture_paint;
-  actor_class->pick             = clutter_texture_pick;
   actor_class->get_paint_volume = clutter_texture_get_paint_volume;
   actor_class->realize          = clutter_texture_realize;
   actor_class->unrealize        = clutter_texture_unrealize;
@@ -1261,11 +1177,9 @@ clutter_texture_init (ClutterTexture *self)
   priv->repeat_y          = FALSE;
   priv->sync_actor_size   = TRUE;
   priv->fbo_handle        = NULL;
-  priv->pick_pipeline     = NULL;
   priv->keep_aspect_ratio = FALSE;
   priv->pick_with_alpha   = FALSE;
   priv->pick_with_alpha_supported = TRUE;
-  priv->seen_create_pick_pipeline_warning = FALSE;
 
   if (G_UNLIKELY (texture_template_pipeline == NULL))
     {
@@ -3048,13 +2962,8 @@ clutter_texture_set_pick_with_alpha (ClutterTexture *texture,
   if (priv->pick_with_alpha == pick_with_alpha)
     return;
 
-  if (!pick_with_alpha && priv->pick_pipeline != NULL)
-    {
-      cogl_object_unref (priv->pick_pipeline);
-      priv->pick_pipeline = NULL;
-    }
+  g_assert (!pick_with_alpha);  /* No longer supported */
 
-  /* NB: the pick pipeline is created lazily when we first pick */
   priv->pick_with_alpha = pick_with_alpha;
 
   /* NB: actors are expected to call clutter_actor_queue_redraw when

src/compositor/meta-surface-actor.c

@@ -147,38 +147,23 @@ meta_surface_actor_pick (ClutterActor       *actor,
   else
     {
       int n_rects;
-      float *rectangles;
       int i;
-      CoglPipeline *pipeline;
-      CoglContext *ctx;
-      CoglFramebuffer *fb;
-      CoglColor cogl_color;
 
       n_rects = cairo_region_num_rectangles (priv->input_region);
-      rectangles = g_alloca (sizeof (float) * 4 * n_rects);
 
       for (i = 0; i < n_rects; i++)
         {
           cairo_rectangle_int_t rect;
-          int pos = i * 4;
+          ClutterActorBox box;
 
           cairo_region_get_rectangle (priv->input_region, i, &rect);
 
-          rectangles[pos + 0] = rect.x;
-          rectangles[pos + 1] = rect.y;
-          rectangles[pos + 2] = rect.x + rect.width;
-          rectangles[pos + 3] = rect.y + rect.height;
+          box.x1 = rect.x;
+          box.y1 = rect.y;
+          box.x2 = rect.x + rect.width;
+          box.y2 = rect.y + rect.height;
+          clutter_actor_pick_box (actor, &box);
         }
-
-      ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
-      fb = cogl_get_draw_framebuffer ();
-
-      cogl_color_init_from_4ub (&cogl_color, color->red, color->green, color->blue, color->alpha);
-
-      pipeline = cogl_pipeline_new (ctx);
-      cogl_pipeline_set_color (pipeline, &cogl_color);
-      cogl_framebuffer_draw_rectangles (fb, pipeline, rectangles, n_rects);
-      cogl_object_unref (pipeline);
     }
 
   clutter_actor_iter_init (&iter, actor);

src/tests/clutter/conform/actor-pick.c

@@ -7,7 +7,6 @@
 #define STAGE_HEIGHT 480
 #define ACTORS_X 12
 #define ACTORS_Y 16
-#define SHIFT_STEP STAGE_WIDTH / ACTORS_X
 
 typedef struct _State State;
 
@@ -22,84 +21,11 @@ struct _State
   gboolean pass;
 };
 
-struct _ShiftEffect
-{
-  ClutterShaderEffect parent_instance;
-};
-
-struct _ShiftEffectClass
-{
-  ClutterShaderEffectClass parent_class;
-};
-
-typedef struct _ShiftEffect       ShiftEffect;
-typedef struct _ShiftEffectClass  ShiftEffectClass;
-
-#define TYPE_SHIFT_EFFECT        (shift_effect_get_type ())
-
-GType shift_effect_get_type (void);
-
-G_DEFINE_TYPE (ShiftEffect,
-               shift_effect,
-               CLUTTER_TYPE_SHADER_EFFECT);
-
-static void
-shader_paint (ClutterEffect           *effect,
-              ClutterEffectPaintFlags  flags)
-{
-  ClutterShaderEffect *shader = CLUTTER_SHADER_EFFECT (effect);
-  float tex_width;
-  ClutterActor *actor =
-    clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (effect));
-
-  if (g_test_verbose ())
-    g_debug ("shader_paint");
-
-  clutter_shader_effect_set_shader_source (shader,
-    "uniform sampler2D tex;\n"
-    "uniform float step;\n"
-    "void main (void)\n"
-    "{\n"
-    "  cogl_color_out = texture2D(tex, vec2 (cogl_tex_coord_in[0].s + step,\n"
-    "                                        cogl_tex_coord_in[0].t));\n"
-    "}\n");
-
-  tex_width = clutter_actor_get_width (actor);
-
-  clutter_shader_effect_set_uniform (shader, "tex", G_TYPE_INT, 1, 0);
-  clutter_shader_effect_set_uniform (shader, "step", G_TYPE_FLOAT, 1,
-                                     SHIFT_STEP / tex_width);
-
-  CLUTTER_EFFECT_CLASS (shift_effect_parent_class)->paint (effect, flags);
-}
-
-static void
-shader_pick (ClutterEffect           *effect,
-             ClutterEffectPaintFlags  flags)
-{
-  shader_paint (effect, flags);
-}
-
-static void
-shift_effect_class_init (ShiftEffectClass *klass)
-{
-  ClutterEffectClass *shader_class = CLUTTER_EFFECT_CLASS (klass);
-
-  shader_class->paint = shader_paint;
-  shader_class->pick = shader_pick;
-}
-
-static void
-shift_effect_init (ShiftEffect *self)
-{
-}
-
 static const char *test_passes[] = {
   "No covering actor",
   "Invisible covering actor",
   "Clipped covering actor",
   "Blur effect",
-  "Shift effect",
 };
 
 static gboolean
@@ -167,30 +93,10 @@ on_timeout (gpointer data)
           if (g_test_verbose ())
             g_print ("With blur effect:\n");
         }
-      else if (test_num == 4)
-        {
-          if (!clutter_feature_available (CLUTTER_FEATURE_SHADERS_GLSL))
-            continue;
-
-          clutter_actor_hide (over_actor);
-          clutter_actor_remove_effect_by_name (CLUTTER_ACTOR (state->stage),
-                                               "blur");
-
-          clutter_actor_add_effect_with_name (CLUTTER_ACTOR (state->stage),
-                                              "shift",
-                                              g_object_new (TYPE_SHIFT_EFFECT,
-                                                            NULL));
-
-          if (g_test_verbose ())
-            g_print ("With shift effect:\n");
-        }
 
       for (y = 0; y < ACTORS_Y; y++)
         {
-          if (test_num == 4)
-            x = 1;
-          else
-            x = 0;
+          x = 0;
 
           for (; x < ACTORS_X; x++)
             {
@@ -200,9 +106,6 @@ on_timeout (gpointer data)
 
               pick_x = x * state->actor_width + state->actor_width / 2;
 
-              if (test_num == 4)
-                pick_x -= SHIFT_STEP;
-
               actor =
                 clutter_stage_get_actor_at_pos (CLUTTER_STAGE (state->stage),
                                                 CLUTTER_PICK_ALL,

src/tests/clutter/conform/meson.build

@@ -33,13 +33,13 @@ clutter_conform_tests_general_tests = [
   'interval',
   'script-parser',
   'units',
+  'point',
 ]
 
 clutter_conform_tests_deprecated_tests = [
   'behaviours',
   'group',
   'rectangle',
-  'texture',
 ]
 
 clutter_conform_tests = []

src/tests/clutter/conform/point.c

@@ -0,0 +1,84 @@
+#include "tests/clutter-test-utils.h"
+
+#include <clutter/clutter.h>
+
+static void
+point_on_nonempty_quadrilateral (void)
+{
+  int p;
+  static const ClutterPoint vertices[4] =
+    {
+      { 1.f, 2.f },
+      { 6.f, 3.f },
+      { 7.f, 6.f },
+      { 0.f, 5.f }
+    };
+  static const ClutterPoint points_inside[] =
+    {
+      { 2.f, 3.f },
+      { 1.f, 4.f },
+      { 5.f, 5.f },
+      { 4.f, 3.f },
+    };
+  static const ClutterPoint points_outside[] =
+    {
+      { 3.f, 1.f },
+      { 7.f, 4.f },
+      { 4.f, 6.f },
+      { 99.f, -77.f },
+      { -1.f, 3.f },
+      { -8.f, -8.f },
+      { 11.f, 4.f },
+      { -7.f, 4.f },
+    };
+
+  for (p = 0; p < G_N_ELEMENTS (points_inside); p++)
+    {
+      const ClutterPoint *point = &points_inside[p];
+
+      g_assert_true (clutter_point_inside_quadrilateral (point, vertices));
+    }
+
+  for (p = 0; p < G_N_ELEMENTS (points_outside); p++)
+    {
+      const ClutterPoint *point = &points_outside[p];
+
+      g_assert_false (clutter_point_inside_quadrilateral (point, vertices));
+    }
+}
+
+static void
+point_on_empty_quadrilateral (void)
+{
+  int p;
+  static const ClutterPoint vertices[4] =
+    {
+      { 5.f, 6.f },
+      { 5.f, 6.f },
+      { 5.f, 6.f },
+      { 5.f, 6.f },
+    };
+  static const ClutterPoint points_outside[] =
+    {
+      { 3.f, 1.f },
+      { 7.f, 4.f },
+      { 4.f, 6.f },
+      { 99.f, -77.f },
+      { -1.f, 3.f },
+      { -8.f, -8.f },
+    };
+
+  for (p = 0; p < G_N_ELEMENTS (points_outside); p++)
+    {
+      const ClutterPoint *point = &points_outside[p];
+
+      g_assert_false (clutter_point_inside_quadrilateral (point, vertices));
+    }
+
+  g_assert_false (clutter_point_inside_quadrilateral (&vertices[0], vertices));
+}
+
+CLUTTER_TEST_SUITE (
+  CLUTTER_TEST_UNIT ("/point/on_nonempty_quadrilateral", point_on_nonempty_quadrilateral)
+  CLUTTER_TEST_UNIT ("/point/on_empty_quadrilateral", point_on_empty_quadrilateral)
+)

src/tests/clutter/conform/texture.c

@@ -1,86 +0,0 @@
-#define CLUTTER_DISABLE_DEPRECATION_WARNINGS
-#include <clutter/clutter.h>
-#include <string.h>
-
-#include "tests/clutter-test-utils.h"
-
-static CoglHandle
-make_texture (void)
-{
-  guint32 *data = g_malloc (100 * 100 * 4);
-  int x;
-  int y;
-
-  for (y = 0; y < 100; y ++)
-    for (x = 0; x < 100; x++)
-      {
-        if (x < 50 && y < 50)
-          data[y * 100 + x] = 0xff00ff00;
-        else
-          data[y * 100 + x] = 0xff00ffff;
-      }
-  return cogl_texture_new_from_data (100,
-                                     100,
-                                     COGL_TEXTURE_NONE,
-                                     COGL_PIXEL_FORMAT_ARGB_8888,
-                                     COGL_PIXEL_FORMAT_ARGB_8888,
-                                     400,
-                                     (guchar *)data);
-}
-
-static void
-texture_pick_with_alpha (void)
-{
-  ClutterTexture *tex = CLUTTER_TEXTURE (clutter_texture_new ());
-  ClutterStage *stage = CLUTTER_STAGE (clutter_test_get_stage ());
-  ClutterActor *actor;
-
-  clutter_texture_set_cogl_texture (tex, make_texture ());
-
-  clutter_actor_add_child (CLUTTER_ACTOR (stage), CLUTTER_ACTOR (tex));
-
-  clutter_actor_show (CLUTTER_ACTOR (stage));
-
-  if (g_test_verbose ())
-    {
-      g_print ("\nstage = %p\n", stage);
-      g_print ("texture = %p\n\n", tex);
-    }
-
-  clutter_texture_set_pick_with_alpha (tex, TRUE);
-  if (g_test_verbose ())
-    g_print ("Testing with pick-with-alpha enabled:\n");
-
-  /* This should fall through and hit the stage: */
-  actor = clutter_stage_get_actor_at_pos (stage, CLUTTER_PICK_ALL, 10, 10);
-  if (g_test_verbose ())
-    g_print ("actor @ (10, 10) = %p\n", actor);
-  g_assert (actor == CLUTTER_ACTOR (stage));
-
-  /* The rest should hit the texture */
-  actor = clutter_stage_get_actor_at_pos (stage, CLUTTER_PICK_ALL, 90, 10);
-  if (g_test_verbose ())
-    g_print ("actor @ (90, 10) = %p\n", actor);
-  g_assert (actor == CLUTTER_ACTOR (tex));
-  actor = clutter_stage_get_actor_at_pos (stage, CLUTTER_PICK_ALL, 90, 90);
-  if (g_test_verbose ())
-    g_print ("actor @ (90, 90) = %p\n", actor);
-  g_assert (actor == CLUTTER_ACTOR (tex));
-  actor = clutter_stage_get_actor_at_pos (stage, CLUTTER_PICK_ALL, 10, 90);
-  if (g_test_verbose ())
-    g_print ("actor @ (10, 90) = %p\n", actor);
-  g_assert (actor == CLUTTER_ACTOR (tex));
-
-  clutter_texture_set_pick_with_alpha (tex, FALSE);
-  if (g_test_verbose ())
-    g_print ("Testing with pick-with-alpha disabled:\n");
-
-  actor = clutter_stage_get_actor_at_pos (stage, CLUTTER_PICK_ALL, 10, 10);
-  if (g_test_verbose ())
-    g_print ("actor @ (10, 10) = %p\n", actor);
-  g_assert (actor == CLUTTER_ACTOR (tex));
-}
-
-CLUTTER_TEST_SUITE (
-  CLUTTER_TEST_UNIT ("/texture/pick-with-alpha", texture_pick_with_alpha)
-)