Fix bloom wasm support

[vallrand]

Objective

• Fixes WASM does not work with HDR #7352

Solution

GLES doesn't support binding specific mip levels for sampling. Fallback to using separate textures instead.

• wgpu-hal/src/gles/device.rs

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[mockersf]

Nice, thank you for doing this!

Could you set wasm to true in https://github.com/vallrand/bevy/blob/wasm-bloom/Cargo.toml#L277 and https://github.com/vallrand/bevy/blob/wasm-bloom/Cargo.toml#L538?

[JMS55]

Needs a comment in the code explaining why we need a fallback for webgl2 and how the fallback is multiple textures instead of mips.

Also, did you test that this works ok in practice? Iirc there are problems with HDR on wasm (maybe only when used with MSAA?), regardless of bloom.

[mockersf]

works for me in WebGL2

[JMS55]

This shouldn't work? See https://docs.rs/bevy/latest/bevy/prelude/struct.Camera.html#structfield.hdr

Turning hdr on uses Rgba16Float textures for the ViewTarget, which shouldn't work with MSAA, and supposedly should outright crash with MSAA + WebGL2.

EDIT: Tried it myself, works fine 👀. Guess it got fixed on wgpu's end. I'll open a PR to update the docs.

[JMS55]

#8634

[MAG-AdrianMeredith]

just out of interest, does this workaround apply to webgpu version of wasm?

[mockersf]

No, bloom already works in WebGPU, you can check it here on a compatible browser: https://bevyengine.org/examples-webgpu/2D%20Rendering/bloom-2d/

This fix is only for WebGL2