Alloy

A Swift Metal framework for GPU-accelerated image processing. Chain shader operations with a builder pattern to build computer vision pipelines that run entirely on the GPU.

Zero external dependencies. macOS 14.0+. Swift 5.9+.

Usage

import Alloy

// Initialize the engine
guard let engine = CommonMetalEngine() else { return }

// Process raw Bayer sensor data
let result = try engine
    .withRawData(width: 1024, height: 1024, bitDepth: 16)
    .debayerRGGB()
    .grayscale(strategy: .luminance)
    .blur(radius: 3)
    .execute(data: rawSensorData)

// Or start from RGBA data
let cropped = try engine
    .withRGBAData(width: 512, height: 512)
    .squareCrop(center: (x: 256, y: 256), sideLength: 200)
    .donutMask(innerRadius: 20)
    .execute(data: rgbaData)

// Access results
let texture = result.texture
let image = result.asNSImage()

Shader Operations

Operation	Description
Debayer	RGGB Bayer pattern demosaicing (8-bit and 16-bit)
Grayscale	Luminance conversion with 8 strategies
Blur	Gaussian blur with configurable radius
Erosion	Morphological erosion (4 or 8-connectivity, 1-20 iterations)
Invert	Color inversion
Noise	Random noise injection
Peak Detection	Local intensity maxima detection with threshold filtering
Square Crop	Region extraction around a center point
Donut Mask	Circular mask with configurable inner/outer radii
HSV Position	HSV-to-position mapping for visualization
Color Sampling	GPU-accelerated color extraction at arbitrary positions
Connected Components	Blob detection with centroid calculation

Installation

Add as a Swift Package dependency:

.package(path: "../alloy/Alloy")

Then add "Alloy" to your target's dependencies.

Architecture

• CommonMetalEngine -- Builder-pattern entry point that chains operations and manages execution
• MetalEngine -- Base class handling Metal device, command queue, and pipeline state caching
• ShaderOperation -- Protocol each GPU operation conforms to
• Metal shaders -- 12 compute kernels in Sources/Alloy/Shaders/

Each operation has three parts: a parameter model (Models/), a Metal compute kernel (Shaders/), and a Swift builder extension (Extensions/).

Building

cd Alloy
swift build
swift test

License

Private repository.