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.
Each render backend keeps track of a stack of BlenModes,
which are pushed and popped by 'core' as we render objects
in the displaay tree. For now, I've just implemented BlendMode.ADD,
which maps directly onto blend mode supported by each backend.
All other blend modes (besides 'NORMAL') will produce a warning
when we try to render using them. This may produce a very large amount
of log output, but it's simpler than emitting each warning only once,
and will help to point developers in the right direction when they
get otherwise inexplicable rendering issues (due to a blend mode
not being implemented).
The wgpu implementation is by far the most complicated, as we need
to construct a `RenderPipeline` for each possible
`(BlendMode, MaskState)`. I haven't been able to find any documentation
about the maximum supported number of (simultaneous) WebGPU render
pipelines - if this becomes an issue, we may need to register them
on-demand when a particular blend mode is requested.
A zero 'index' does not have a subsequent 'kind' field in the
written SWF. The 'index' field is not actually used for
true/false/undefined/null, so it can be anything as long
as it's non-zero.
This PR implements the 'DisplayObject.transform' getters/setters,
and most of the getters/setters in the `Transform` class
From testing in FP, it appears that each call to the
'DisplayObject.transform' property produces a new
'Transform' instance, which is permanently tied to the
owner 'DisplayObject'. All of the getters/setters in
`Transform` operate directly on owner `DisplayObject`.
However, note that the `Matrix` and `ColorTransform`
valuse *produced* the getter are plain ActionScript objects,
and have no further tie to the `DisplayObject`.
Using the `DisplayObject.transform` setter results in
values being *copied* from the input `Transform` object.
The input object retains its original owner `DisplayObject`.
Not implemented:
* Transform.concatenatedColorTransform
* Transform.pixelBounds
When a DisplayObject is not a descendant of the stage,
the `concatenatedMatrix` property produces a bizarre matrix:
a scale matrix that the depends on the global state quality.
Any DisplayObject that *is* a descendant of the stage has
a `concatenatedMatrix` that does not depend on the stage quality.
I'm not sure why the behavior occurs - for now, I just manually
mimic the values prdduced by FP. However, these values may indicate
that we need to do some internal scaling based on stage quality values,
and then 'undo' this in certain circumstances when constructing
an ActionScript matrix.
Unfortunately, some of the computed 'concatenatedMatrix' values
are off by f32::EPSILON. This is likely due to us storing some
internal values in pixels rather than twips (the rounding introduced
by round-trip twips conversions could cause this slight difference0.
For now, I've opted to mark these tests as 'approximate'.
To support this, I've extended our test framework to support providing
a regex that matches floating-point values in the output. This allows
us to print out 'Matrix.toString()' and still perform approximate
comparisons between strings of the format
'(a=0, b=0, c=0, d=0, tx=0, ty=0)'
Daniel Jacobs