`BitmapHandle` now holds `Arc<dyn BitmapHandleImpl>`.
This allows us to move all of the per-bitmap backend data into
`BitmapHandle`, instead of holding an id to a backend-specific
hashmap.
This fixes the memory leak issue with bitmaps. Once the AVM side of a
bitmap (`Bitmap`/`BitmapData`) gets garbage-collected, the
`BitmapHandle` will get dropped, freeing all of the GPU resources
assoicated with the bitmap.
We only called `get_bitmap_pixels` when creating a `BitmapData`
for an SWF-provided `Bitmap`. We now store the initial pixels
in `Character::Bitmap`, and use them to initialize a `BitmapData`
when needed.
This lets us simplify the wgpu backend, which no longer needs
to store a `Bitmap` object. In addition to saving space for
`BitmapData` objects that lack an SWF `Bitmap`, this will make
it easier to move data from `bitmap_registry` into `BitmapHandle`
itself.
Currently, we rely on ShapeTessellator being able to get a BitmapHandle
without a RenderBackend. With the upcoming BitmapData refactor,
we will always need a RenderBackend to get a BitmapHandle, which creates
borrow-checker issues in ShapeTessellator (which is stored in a
RenderBackend).
To solve this, we split BitmapSource.bitmap into two methods -
BitmapSource.bitmap and BitmapSource.bitmap_handle. ShapeTessellator
continues to use BitmapSource.bitmap, and uses the u16 bitmap id
instead of a BitmapHandle. The BitmapSource.bitmap_handle method
is used inside each render backend to convert the id to a BitmapHandle,
avoiding borrow-checker issues.
We now check if a BitmapData has been disposed by checking
for a zero width or height (which cannot happen otherwise).
As a result, we no longer need the 'disposed' field on the AVM1
BitmapData object.
It was only used to make structs `#[derive(gc_arena::Collect)]`, and
generally it doesn't make much sense that `render` needs to be GC-aware.
So instead annotate `render` fields in `core` with `#[collect(require_static)]`.
Aaron Hill