> Follow up to #11600 and #10588
@mockersf expressed some [valid
concerns](https://github.com/bevyengine/bevy/pull/11600#issuecomment-1932796498)
about the current system this PR attempts to fix:
The `ComputedTextureSlices` reacts to asset change in both `bevy_sprite`
and `bevy_ui`, meaning that if the `ImageScaleMode` is inserted by
default in the bundles, we will iterate through most 2d items every time
an asset is updated.
# Solution
- `ImageScaleMode` only has two variants: `Sliced` and `Tiled`. I
removed the `Stretched` default
- `ImageScaleMode` is no longer part of any bundle, but the relevant
bundles explain that this additional component can be inserted
This way, the *absence* of `ImageScaleMode` means the image will be
stretched, and its *presence* will include the entity to the various
slicing systems
Optional components in bundles would make this more straigthfoward
# Additional work
Should I add new bundles with the `ImageScaleMode` component ?
> Replaces #5213
# Objective
Implement sprite tiling and [9 slice
scaling](https://en.wikipedia.org/wiki/9-slice_scaling) for
`bevy_sprite`.
Allowing slice scaling and texture tiling.
Basic scaling vs 9 slice scaling:
Slicing example:
<img width="481" alt="Screenshot 2022-07-05 at 15 05 49"
src="https://user-images.githubusercontent.com/26703856/177336112-9e961af0-c0af-4197-aec9-430c1170a79d.png">
Tiling example:
<img width="1329" alt="Screenshot 2023-11-16 at 13 53 32"
src="https://github.com/bevyengine/bevy/assets/26703856/14db39b7-d9e0-4bc3-ba0e-b1f2db39ae8f">
# Solution
- `SpriteBundlue` now has a `scale_mode` component storing a
`SpriteScaleMode` enum with three variants:
- `Stretched` (default)
- `Tiled` to have sprites tile horizontally and/or vertically
- `Sliced` allowing 9 slicing the texture and optionally tile some
sections with a `Textureslicer`.
- `bevy_sprite` has two extra systems to compute a
`ComputedTextureSlices` if necessary,:
- One system react to changes on `Sprite`, `Handle<Image>` or
`SpriteScaleMode`
- The other listens to `AssetEvent<Image>` to compute slices on sprites
when the texture is ready or changed
- I updated the `bevy_sprite` extraction stage to extract potentially
multiple textures instead of one, depending on the presence of
`ComputedTextureSlices`
- I added two examples showcasing the slicing and tiling feature.
The addition of `ComputedTextureSlices` as a cache is to avoid querying
the image data, to retrieve its dimensions, every frame in a extract or
prepare stage. Also it reacts to changes so we can have stuff like this
(tiling example):
https://github.com/bevyengine/bevy/assets/26703856/a349a9f3-33c3-471f-8ef4-a0e5dfce3b01
# Related
- [ ] Once #5103 or #10099 is merged I can enable tiling and slicing for
texture sheets as ui
# To discuss
There is an other option, to consider slice/tiling as part of the asset,
using the new asset preprocessing but I have no clue on how to do it.
Also, instead of retrieving the Image dimensions, we could use the same
system as the sprite sheet and have the user give the image dimensions
directly (grid). But I think it's less user friendly
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
