c156fa9ad3
A single `Writer` can be reused to convert any number of Naga IR modules to SPIR-V. This lets us reuse the heap allocations, but makes us responsible for resetting the state of the `Writer` fully between modules. The old code neglected to clear several different fields: logical_layout (all fields), lookup_type, and cached_constants. This commit uses Rust struct literal expressions to construct the re-initialized `Writer`, which makes the compiler check that each field has been handled. It also introduces a policy limiting how much storage will be retained, so that processing the occasional whale doesn't leave us with leviathan buffers permanently.
Naga
The shader translation library for the needs of wgpu and gfx-rs projects.
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 | Fully validated |
| GLSL | 🆗 | glsl-in |
| Back-end | Status | Feature | Notes |
|---|---|---|---|
| SPIR-V | ✅ | spv-out | |
| WGSL | 🆗 | wgsl-out | |
| Metal | ✅ | msl-out | |
| HLSL | 🚧 | hlsl-out | Shader Model 5.0+ (DirectX 11+) |
| 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, which allows to test the conversion of different code paths.
cargo run my_shader.wgsl # validate only
cargo run my_shader.spv my_shader.txt # dump the IR module into a file
cargo run 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 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 --workspace,
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
make validate-wgsl # for WGSL shaders
make validate-hlsl # for HLSL shaders. Note: this Make target makes use of the "sh" shell. This is not the default shell in Windows.