There is no need to make CoglJournal a CoglObject, nor any kind of
object for that matter, since it doesn't require refcounting at all.
CoglJournal is entirely private to, and managed by, CoglFramebuffer,
and it only needs to create and destroy it.
Make CoglJournal a free-form struct, and adjust CoglFramebuffer to
call _cogl_journal_free() instead of cogl_object_unref().
Related: https://gitlab.gnome.org/GNOME/mutter/-/issues/2087
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2355>
CoglJournal tracks a few OpenGL states so that they can
be batch-applied if necessary. It also has a nice property
of allowing purely CPU-based glReadPixels() when the scene
is composed of simple rectangles.
However, the current journal implementation leaves various
other GL states out, such as dithering and the viewport.
In Clutter, that causes the journal to be flushed when
picking, touching the GPU when we didn't really need to.
Track the viewport of the framebuffer in the journal so that
we can avoid flushing the journal so often.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/402
This basically reverts commit 54735dec, which tried to avoid the
GLib-defined types in favor the standard C ones. One exception to this
is the bool type, for which the commit introduces a new type CoglBool.
Let's just get rid of this type in favor of having consistency with the
GLib types. Note by the way that neither CoglBool nor gboolean (which
has a size of `int`) are completely compatible with bool (size `char`).
https://gitlab.gnome.org/GNOME/mutter/merge_requests/321
