Anodize

Type safety for Metal. 🤘

Used in Sculptura

Suppose we've got the following MSL kernel:

kernel void MyCoolKernel(device float* buffer,
                         constant float& value,
                         uint tid [[thread_position_in_grid]]) {
    buffer[tid] += value;
}

Running swift run Anodize MyCoolKernel.metal -o Anodized.swift generates the file Anodized.swift which contains wrappers for our kernel(s).

And then call the kernel from Swift with type safety, without worrying about binding indices. 😎

let device = MTLCreateSystemDefaultDevice()!
let kernel = MyCoolKernel(device: device)

let array = try MutableGPUArray<Float>(data: [1,2,3])

let queue = device.makeCommandQueue()!
let buf = queue.makeCommandBuffer()!

try kernel
    .begin(buf)
    .buffer(array)
    .value(bytes: 1)
    .dispatch(threads: 3, threadsPerThreadgroup: 1)
    .end()

buf.commit()
buf.waitUntilCompleted()

print("array: \(array.array)") // prints [2.0, 3.0, 4.0]
        

Notes

• Type safety is limited by Metal's reflection API. For user-defined types, we can only check the size is what is expected (this seems reasonably good).
• You can adopt Anodize gradually in your codebase (as I'm doing in Sculptura).
• You don't have to use GPUArray, you can make another class that conforms to GPUBufferProvider.
• You can pass a raw MTLBuffer but you'll lose type safety (at least the binding indices will be correct).
• Vertex and fragment functions aren't yet supported.