6701e2bf96
Non-exhaustive matches on `Expression` make it harder to review changes that add new enum variants, because the compiler can't tell you that you've missed a case. Although I believe Clippy is able to do so, I don't think we should make a blanket rule of forbidding wildcard match arms against `Expression`. There are a few matches that are only concerned with a handful of variants, or a single variant. For example, variant, naga::front::spv::Parser::next_block is only concerned with whether an expression is a constant or not. In principle, these sites should also be checked when adding a new variant, but it seems too burdensome to require them to list all the `Expression` variants they don't care about. The principle should be applied only to matches that are already handling most variants. At the moment, there is only one such match on `Expression` in the code base, and it's only missing a few variants, so this is quick to fix.
Naga
This is an experimental shader translation library for the needs of gfx-rs project and WebGPU.
Supported end-points
Everything is still work-in-progress, but some end-points are usable:
| Front-end | Status | Feature | Notes |
|---|---|---|---|
| SPIR-V (binary) | ✅ | spv-in | |
| WGSL | ✅ | wgsl-in | |
| GLSL | 🆗 | glsl-in | Vulkan flavor is expected |
| Rust |
| Back-end | Status | Feature | Notes |
|---|---|---|---|
| SPIR-V | ✅ | spv-out | |
| WGSL | |||
| Metal | ✅ | msl-out | |
| HLSL | 🚧 | hlsl-out | |
| GLSL | 🆗 | glsl-out | |
| AIR | |||
| DXIL/DXIR | |||
| DXBC | |||
| DOT (GraphViz) | 🆗 | dot-out | Not a shading language |
✅ = Primary support — 🆗 = Secondary support — 🚧 = Unsupported, but support in progress
Conversion tool
Naga includes a default binary target "convert", which allows to test the conversion of different code paths.
cargo run --features spv-in -- my_shader.spv # dump the IR module to debug output
cargo run --features spv-in,msl-out -- my_shader.spv my_shader.metal --flow-dir flow-dir # convert the SPV to Metal, also dump the SPIR-V flow graph to `flow-dir`
cargo run --features wgsl-in,glsl-out -- my_shader.wgsl my_shader.vert --profile es310 # convert the WGSL to GLSL vertex stage under ES 3.20 profile
Development workflow
The main instrument aiding the development is the good old cargo test --all-features,
which will run the unit tests, and also update all the snapshots. You'll see these
changes in git before committing the code.
If working on a particular front-end or back-end, it may be convenient to
enable the relevant features in Cargo.toml, e.g.
default = ["spv-out"] #TEMP!
This allows IDE basic checks to report errors there, unless your IDE is sufficiently configurable already.
Finally, when changes to the snapshots are made, we should verify that the produced shaders
are indeed valid for the target platforms they are compiled for. We automate this with Makefile:
make validate-spv # for Vulkan shaders, requires SPIRV-Tools installed
make validate-msl # for Metal shaders, requires XCode command-line tools installed
make validate-glsl # for OpenGL shaders, requires GLSLang installed
make validate-dot # for dot files, requires GraphViz installed