Previously, we were scaling down the source image to fit into
the smaller sourceRect, instead of cropping at the original scale.
This broke the background textures in Fancy Pants World 4 Part 2,
as the scaled-down output image resulted in a smaller rectangle
being returned from 'getColorBoundsRect'
We now crop the image by properly constructing the UV-coordinate
transformation matrix. We were also using the wrong value for the
'destPoint' y coordinate, which I fixed.
This slightly changes the image output of two tests - the new images
now more closely match the Flash output.
When rendering to an offscreen texture for `Bitmapdata.draw`,
we first render to a temporary frame buffer, and then copy the contents
of the frame buffer back to the target texture. However, this results
in blend modes being incorrectly applied - for example, rendering with
BlendMode.SUBTRACT will subtract against the framebuffer (which starts
with each pixel as 0x00000000), instead of the previous BitmapData
contents.
To fix this, we now use our texture target as the frame buffer
when performing `render_offscreen`. This ensure that we blend
over existing pixels (taking into account the `blendMode` provided
in the `BitmapData.draw` call).
When multisampling is enabled, we use a copy pipeline to copy
the existing contents of our texture to a fresh multisampled frame
buffer (the non-multisampled texture target becomes our resolve buffer).
`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.