The function _clutter_paint_volume_get_stage_paint_box() actually
doesn't modify the paint volume that's passed to it, so make that a bit
more clear by passing a const paint volume as the argument.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1492>
Instead of 4 planes, use a graphene_frustum_t to store the clipping
planes.
The cautious reviewer might noticed that we are now setting up 6
planes: the 4 planes we were doing before, plus 2 extra planes in
the Z axis. These extra planes simulate an "infinite" Z far, and
an "on-camera" Z near.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1489
CoglMatrix already is a typedef to graphene_matrix_t. This commit
simply drops the CoglMatrix type, and align parameters. There is
no functional change here, it's simply a find-and-replace commit.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1439
