GPUOperator

Metal is used for rendering graphics and performing parallel computations like image processing. But,

there are many boiler plates to use Metal normally.

• Creating Metal device
• Creating command queue
• Creating library, taking caring for which bundle includes it.
• PipelineState, CommandBuffer, Threadgroup ......... 😱

This library simplifies these steps.

Examples

Graphics Shader

Implementation

Thundershower	Fourier Series
Reference	Concept

• Reference: http://glslsandbox.com/

Realtime Video Processing

Implementation

Edge Detection	Color Conversion
Prewitt	Monochrome

Image Processing: Two Images Difference

Implementation

Before	After	Difference

This infers

• Bold font was changed to regular font.
• The last processors. word was removed.
• The border disappeared.

Getting Started

1. Define kernel function and kernel class

#include <metal_stdlib>
using namespace metal;

kernel void monochrome(texture2d<half, access::read_write> dest [[ texture(0) ]],
                       texture2d<half, access::read_write> source [[ texture(1) ]],
                       uint2 gid [[ thread_position_in_grid ]]) {
    half3 color = source.read(gid).rgb;
    half max_color = fmax3(color.r, color.g, color.b);

    dest.write(half4(half3(max_color), 1), gid);
}

import GPUOperator

final class Monochrome: Kernel {
    static let functionName: String = "monochrome"
}

2. Setup GPUOperator instance

let gpuOperator = try? GPUOperator()
try? gpuOperator?.install(kernel: Monochrome())

3. Configure Rendering Process

let renderingView = RenderingView(frame: .zero)
renderingView.gpuOperator = gpuOperator
renderingView.run()

The run() function just starts displaylink process inside RenderingView. If you want to use MTLView (Metal Standard class), following example would be helpful.

import MetalKit
extension ViewController: MTKViewDelegate {
    func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {}

    func draw(in view: MTKView) {
        autoreleasepool {
            guard let drawable = view.currentDrawable else { return }
            gpuOperator?.commit(drawable: drawable)
        }
    }
}

Requirements

• Swift 5.0
• iOS 12.0+
• Any simulators are unsupported.

Installation

Cocoapods

pod 'GPUOperator'

Carthage

github "horita-yuya/GPUOperator"

License

GPUOperator is available under the MIT license.