bevy/crates/bevy_sprite
charlotte 🌸 e6ba9a6d18
Type erased materials (#19667)
# Objective

Closes #18075

In order to enable a number of patterns for dynamic materials in the
engine, it's necessary to decouple the renderer from the `Material`
trait.

This opens the possibility for:
- Materials that aren't coupled to `AsBindGroup`.
- 2d using the underlying 3d bindless infrastructure.
- Dynamic materials that can change their layout at runtime.
- Materials that aren't even backed by a Rust struct at all.

## Solution

In short, remove all trait bounds from render world material systems and
resources. This means moving a bunch of stuff onto `MaterialProperties`
and engaging in some hacks to make specialization work. Rather than
storing the bind group data in `MaterialBindGroupAllocator`, right now
we're storing it in a closure on `MaterialProperties`. TBD if this has
bad performance characteristics.

## Benchmarks

- `many_cubes`:
`cargo run --example many_cubes --release --features=bevy/trace_tracy --
--vary-material-data-per-instance`:
![Screenshot 2025-06-26
235426](https://github.com/user-attachments/assets/10a0ee29-9932-4f91-ab43-33518b117ac5)

- @DGriffin91's Caldera
`cargo run --release --features=bevy/trace_tracy -- --random-materials`

![image](https://github.com/user-attachments/assets/ef91ba6a-8e88-4922-a73f-acb0af5b0dbc)


- @DGriffin91's Caldera with 20 unique material types (i.e.
`MaterialPlugin<M>`) and random materials per mesh
`cargo run --release --features=bevy/trace_tracy -- --random-materials`
![Screenshot 2025-06-27
000425](https://github.com/user-attachments/assets/9561388b-881d-46cf-8c3d-b15b3e9aedc7)


### TODO

- We almost certainly lost some parallelization from removing the type
params that could be gained back from smarter iteration.
- Test all the things that could have broken.
- ~Fix meshlets~

## Showcase

See [the
example](https://github.com/bevyengine/bevy/pull/19667/files#diff-9d768cfe1c3aa81eff365d250d3cbe5a63e8df63e81dd85f64c3c3cd993f6d94)
for a custom material implemented without the use of the `Material`
trait and thus `AsBindGroup`.


![image](https://github.com/user-attachments/assets/e3fcca7c-e04e-4a4e-9d89-39d697a9e3b8)

---------

Co-authored-by: IceSentry <IceSentry@users.noreply.github.com>
Co-authored-by: IceSentry <c.giguere42@gmail.com>
2025-06-27 22:57:24 +00:00
..
src Type erased materials (#19667) 2025-06-27 22:57:24 +00:00
Cargo.toml Update derive_more requirement from 1 to 2 (#19671) 2025-06-24 11:13:04 +00:00
LICENSE-APACHE Cleanup publish process (#17728) 2025-02-09 17:46:19 +00:00
LICENSE-MIT Cleanup publish process (#17728) 2025-02-09 17:46:19 +00:00
README.md Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00

Bevy Sprite

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