clutter/actor: avoid transform node for identity matrix

If the transform matrix is an identity, then positioning wont change and
we can avoid creating the transform node altogether. This is based on
a similar find in GTK today while reducing temporary allocations.

This cuts the number of transforms created in clutter_actor_paint() by
about half under light testing of GNOME Shell from 6.8% to 2.4% of
allocations.

Before:

    ALLOCATED      TOTAL    FUNCTION
[   20.4 MiB] [  21.20%]    clutter_actor_paint
[   11.0 MiB] [  11.45%]      clutter_paint_node_paint
[    6.6 MiB] [   6.84%]      clutter_transform_node_new
[    2.5 MiB] [   2.61%]      clutter_actor_node_new

After:

    ALLOCATED      TOTAL    FUNCTION
[   33.4 MiB] [  24.12%]    clutter_actor_paint
[   26.2 MiB] [  18.91%]      clutter_paint_node_paint
[    3.4 MiB] [   2.43%]      clutter_actor_node_new
[    3.3 MiB] [   2.41%]      clutter_transform_node_new

Allocation amounts will have differed due to different amounts of running
time, but the % of allocations has now dropped below
clutter_actor_node_new() which should be expected.

https://gitlab.gnome.org/GNOME/mutter/issues/1056
This commit is contained in:
Christian Hergert 2020-02-20 06:41:34 +00:00 committed by Jonas Ådahl
parent 44ae38599f
commit d122b66abc

View File

@ -3997,11 +3997,14 @@ clutter_actor_paint (ClutterActor *self,
clutter_actor_get_transform (self, &transform);
if (!cogl_matrix_is_identity (&transform))
{
transform_node = clutter_transform_node_new (&transform);
clutter_paint_node_add_child (transform_node, root_node);
clutter_paint_node_unref (root_node);
root_node = g_steal_pointer (&transform_node);
}
#ifdef CLUTTER_ENABLE_DEBUG
/* Catch when out-of-band transforms have been made by actors not as part