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.
This PR implements core 'stage3D' APIs. We are now able
to render at least two demos from the Context3D docs - a simple
triangle render, and a rotating cube.
Implemented in this PR:
* Stage3D access and Context3D creation
* IndexBuffer3D and VertexBuffer3D creation, uploading, and usage
* Program3D uploading and usage (via `naga-agal`)
* Context3D: configureBackBuffer, clear, drawTriangles, and present
Not yet implemented:
* Any 'dispose()' methods
* Depth and stencil buffers
* Context3D texture apis
* Scissor rectangle
General implementation strategy:
A new `Object` variant is added for each of the Stage3D objects
(VertexBuffer3D, Program3D, etc). This stores a handle to the
parent `Context3D`, and (depending on the object) a handle
to the underlying native resource, via `Rc<dyn
SomeRenderBackendTrait>`).
Calling methods on Context3D does not usually result in an immediate
call to a `wgpu` method. Instead, we queue up commands in our
`Context3D` instance, and execute them all on a call to `present`.
This avoids some nasty wgpu lifetime issues, and is very similar
to the approah we use for normal rendering.
The actual rendering happens on a `Texture`, with dimensions
determined by `createBackBuffer`. During 'Stage' rendering,
we render all of these Stage3D textures *behind* the normal
stage (but in front of the overall stage background color).
When rendering offscreen, we want the resulting image to use
premultiplied alpha, since the image will be stored in a texture.
However, when capturing an image in the exporter or test framework,
we want to use straight alpha, so that the resulting image can
be saved as a PNG.
Previously, we incorrectly used straight alpha everywhere, resulting
in incorrect output when using BitmapData.draw with transparency.
* avm2: Implement `BitmapData.draw` for `wgpu` backend
This method requires us to have the ability to render directly to a
texture. Fortunately, the `wgpu` backend already supports this in
the form of `TextureTarget`. However, the rendering code required
some refactoring in order to avoid creating duplicate `wgpu` resources.
The current implementation blocks on copying the pixels back
from the GPU to the CPU, so that we can immediately set them in
the Ruffle `BitmapData`. This is likely very inefficient, but will
work for a first implementation.
In the future, we could explore allowing the CPU image data and GPU
texture to be out of sync, and only synchronized when explicitly
necessary (e.g. on `getPixel` or `setPixel` calls).
* Rename `with_offscreen_backend` to `render_offscreen` and use Bitmap
* Don't panic when backend doesn't implement `render_offscreen`
Previously, the viewport height and width were stored in
both `Stage` and the `RenderBackend`. Any changes to the viewport
dimensions (e.g. due to window resizing) needed to be updated in both
places to keep our handling of the viewport consistent.
This PR adds a new `ViewportDimensions` type, which holds the
width, height, and scale factor. It is stored inside the
`RenderBackend` impl, and is retrieved using the newly added
method `RenderBackend.get_viewport_dimensions`. After a `Player`
has been constructed, any code that needes access to the viewport
dimensions will ultimate go through this method.
Unfortunately, `Stage` needs to use the viewport dimensions
in `build_matrices`. Therefore, any code modifying the viewport
dimensions should go through `player.set_viewport_dimensions`,
which ensures that the stage matrices are rebuilt after the render
backend is updated.
The captured WGPU texture uses premultiplied alpha.
This image gets saved as a PNG, so it should use straight alpha.
Note that all of our current image tests have 'alpha = 1.0' for all
of the pixels, so this currently has no effect.
Based on the work in #6717, plus additional adaptions mentioned in
https://github.com/gfx-rs/wgpu/blob/master/CHANGELOG.md#wgpu-013-2022-06-30,
and more not-mentioned but required changes.
Also bump `wasm-bindgen` to `0.2.81` (along with its helper crates), as
required by the new `wgpu` version.
Note that I don't fully understand some of the required changes, notably:
* `wgpu::PresentMode::Mailbox` no longer works on my machine (Windows 11) -
The `wgpu` documentation says that `wgpu::PresentMode::Fifo` is the
only guaranteed to be supported, so I switched over to it instead.
* `self.staging_belt.recall()` doesn't return a `Future` anymore -
I assume it became synchronous so I simply removed the `executor`
from there.
Nathan Adams