These are poorly documented, but from looking at OpenFL
and AGALMiniAssembler, they allow performing loads of the
form `vc[va0.x + offset]` - that is, computing a dynamic register
number, instead of using the register number present in the opcode.
In a previous PR, I introduced an optimization that used
`copy_texture_to_texture` to copy directly from a BitmapData GPU
texture to a Stage3D GPU texture.
Unfortunately, this optimization is incorrect. A BitmapData GPU
texture can be modified at any time by normal AVM2 code - in
particular, in might be modified before we submit the encoded
`copy_texture_to_texture` command. This shows up in Sniper Team,
which re-uses BitmapData objects for multiple distinct textures.
The previous 'optimization' resulted in the wrong BitmapData contents
getting uploaded to a texture (since it was changed before the copy
command was submitted).
When multisampling is enabled, we should create a new multisampled texture,
and use the existing texture as the resolve buffer. We also need to
call `update_has_depth_texture` to keep our pipeline aware of whether
or not we currently have a depth buffer attached.
Makes progress on #10641 (it has a stack overflow after
this PR, due to an unrelated issue).
wgpu requires buffer copy sizes and offsets to be 4-byte aligned.
Unfortunately, ActionScript can perform 2-byte aligned uploads
into an IndexBuffer3D.
To support this, we now keep a copy of the IndexBuffer3D on the CPU.
When performing an upload to the buffer, we round the offset down
and the size up to the nearest 4-byte aligned value. The cpu buffer
is used to fill out the write with existing data, so that we don't
corrupt the contents of the GPU buffer.
To avoid introducing a new RefCell, I've changed IndexBuffer3D
to use a `Box` instead of an `Rc` to store the trait object.
This allows us to pass a mutable reference down to the backend.
Generally, when transforming a difference between two points, `p1`
and `p2`, with a matrix `m`, we would like the following property
to hold:
```
m * (p1 - p2) == m * p1 - m * p2
```
Unfortunately, it wasn't like this before, because matrices have a
translation component, which is non-linear. In `m * p1 - m * p2`,
the translations of `m * p1` and `m * p2` are the same and therefore
cancel out each other. However, in `m * (p1 - p2)` the translation
stays.
In order to preserve this property, introduce a new `PointDelta`
type which is not subject to translation when transformed by a matrix.
For now, the following operations are supported:
* `Point - Point -> PointDelta`
* `Point + PointDelta -> Point`
* `Point += PointDelta`
* `Point - PointDelta -> Point`
* `Point -= PointDelta`
As a consequence, the expression `position + global_to_local_matrix * mouse_delta`
in `update_drag()` now ignores translation, which fixes#817.
renovate[bot]