# Overview
Fixes https://github.com/bevyengine/bevy/issues/17869.
# Summary
`WGPU_SETTINGS_PRIO` changes various limits on `RenderDevice`. This is
useful to simulate platforms with lower limits.
However, some plugins only check the limits on `RenderAdapter` (the
actual GPU) - these limits are not affected by `WGPU_SETTINGS_PRIO`. So
the plugins try to use features that are unavailable and wgpu says "oh
no". See https://github.com/bevyengine/bevy/issues/17869 for details.
The PR adds various checks on `RenderDevice` limits. This is enough to
get most examples working, but some are not fixed (see below).
# Testing
- Tested native, with and without "WGPU_SETTINGS=webgl2".
Win10/Vulkan/Nvidia".
- Also WebGL. Win10/Chrome/Nvidia.
```
$env:WGPU_SETTINGS_PRIO = "webgl2"
cargo run --example testbed_3d
cargo run --example testbed_2d
cargo run --example testbed_ui
cargo run --example deferred_rendering
cargo run --example many_lights
cargo run --example order_independent_transparency # Still broken, see below.
cargo run --example occlusion_culling # Still broken, see below.
```
# Not Fixed
While testing I found a few other cases of limits being broken.
"Compatibility" settings (WebGPU minimums) breaks native in various
examples.
```
$env:WGPU_SETTINGS_PRIO = "compatibility"
cargo run --example testbed_3d
In Device::create_bind_group_layout, label = 'build mesh uniforms GPU early occlusion culling bind group layout'
Too many bindings of type StorageBuffers in Stage ShaderStages(COMPUTE), limit is 8, count was 9. Check the limit `max_storage_buffers_per_shader_stage` passed to `Adapter::request_device`
```
`occlusion_culling` breaks fake webgl.
```
$env:WGPU_SETTINGS_PRIO = "webgl2"
cargo run --example occlusion_culling
thread '<unnamed>' panicked at C:\Projects\bevy\crates\bevy_render\src\render_resource\pipeline_cache.rs:555:28:
index out of bounds: the len is 0 but the index is 2
Encountered a panic in system `bevy_render::renderer::render_system`!
```
`occlusion_culling` breaks real webgl.
```
cargo run --example occlusion_culling --target wasm32-unknown-unknown
ERROR app: panicked at C:\Users\T\.cargo\registry\src\index.crates.io-1949cf8c6b5b557f\glow-0.16.0\src\web_sys.rs:4223:9:
Tex storage 2D multisample is not supported
```
OIT breaks fake webgl.
```
$env:WGPU_SETTINGS_PRIO = "webgl2"
cargo run --example order_independent_transparency
In Device::create_bind_group, label = 'mesh_view_bind_group'
Number of bindings in bind group descriptor (28) does not match the number of bindings defined in the bind group layout (25)
```
OIT breaks real webgl
```
cargo run --example order_independent_transparency --target wasm32-unknown-unknown
In Device::create_render_pipeline, label = 'pbr_oit_mesh_pipeline'
Error matching ShaderStages(FRAGMENT) shader requirements against the pipeline
Shader global ResourceBinding { group: 0, binding: 34 } is not available in the pipeline layout
Binding is missing from the pipeline layout
```
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