Slang Shader Development

Work with the Slang shader language: configure builds, format code, write tests, debug instructions, and follow contribution guidelines.

Build Configuration

Slang is pre-built in debug configuration. Targets like `slangc`, `slang-test`, and `slangi` are ready to run.

**To rebuild after changes:**

1. Configure CMake:

```bash

cmake --preset default

```

2. Build debug workflow:

```bash

cmake --workflow --preset debug

```

3. Consult `docs/building.md` for detailed build instructions.

Code Formatting

**CRITICAL: Format before committing.**

Run the formatting script before submitting any PR:

```bash

./extras/formatting.sh

```

All PRs must adhere to the project's coding style. Unformatted code will not be accepted.

Pull Request Labels

Every PR requires one of these labels:

- Public API changes break ABI compatibility

- Language changes cause existing Slang code to error

Breaking changes are rare. Default to non-breaking unless certain.

Debugging Instructions

When debugging problematic instructions, trace their creation using `_debugUID`.

**Example:** If instruction `_debugUID=1234` is buggy:

```bash

python3 ./extras/insttrace.py 1234 ./build/Debug/bin/slangc tests/my-test.slang -target spirv

```

This prints the callstack where the instruction was created.

Writing Tests

All bug fixes and features should include regression tests.

**Test location:** `tests/` directory (`.slang` files)

**Run tests:**

```bash

slang-test tests/path/to/your-new-test.slang

```

Build `slang-test` target first if needed.

CPU-Based Tests (No GPU Required)

For non-GPU-specific features, run tests on CPU:

```slang

//TEST:COMPARE_COMPUTE(filecheck-buffer=CHECK):-output-using-type -cpu

```

**Example:** `tests/language-feature/lambda/lambda-0.slang`

Interpreter Tests (Bytecode)

Use `slangi` for logic validation:

```slang

//TEST:INTERPRET(filecheck=CHECK):

void main()

{

//CHECK: hello!

printf("hello!");

}

```

GPU-Specific Tests

Cannot run locally (D3D12, Vulkan, Metal, WGSL). Submit PR and let CI verify.

Important Notes