The fix in #5218 wasn't sufficient; 30-bit arithmetic should be used
along all the way when calculating an effective sound transform.
For example, a sound transform composited by volumes `-0x80000000` and
`25` should end up as effectively 0, whereas previously it would have
been calculated as `-0x80000000 * 25 / 100 = -0x20000000`, which is a
30-bit integer that hasn't been truncated.
Fixes#5655.
This also necessitated removing the `impl_display_object` family of macros, as you cannot name a field of a field in a macro expression. I tried. So instead I've reverted to standard default method inheritance, in the same way we did with AVM2 objects.
`handle_clip_event` is now a default trait method that calls three methods in order:
* `filter_clip_event`, to determine which events that either this object or it's children may handle
* `propagate_to_children`, to check if any children of this object want to handle an event. (This also includes AVM2 button states, which are not technically "children" in the usual sense...)
* `event_dispatch`, which does the actual "object reacts to an event" bit if no child handles the object.
These roughly correspond to phases of existing event-handling objects pre-`InteractiveObject`.
* Rename movie_clip::ClipAction to movie_clip::ClipEventHandler.
* Store the swf::ClipEventFlag event flags that trigger the event
directly in the event handler. Previously we split up any event
that had multiple event flags into separate events. Now these
can be kept as a single event.
* Remove `MovieClip::has_button_event`, and instead store the
union of all event flags in `MovieClip::clip_event_flags`. This
will be useful for other cases in the future.
A `PlaceObjectAction::Replace` signals that a shape should
be swapped with a different shape. Previously we instantiated a
completely new `Graphic`, but this is incorrect; instead the
underlying shape handle should be swapped out, but the outer object
remains. This is visible in AVM2 where you can access `Shape` as
a normal display object.
Matrices in an SWF file store their scale/skew components in
in 16.16 format (fbits).
Split `ruffle_core::Matrix` and `swf::Matrix`. `swf::Matrix` now
stores its data as `Fixed16` instead of immediately converting to
`f32`.
Mike Welsh