s1ddok/alloy

Other Alloy-specific types

Other types that are introduces my Alloy are

• MTLOffscreenRenderer: this is a class that lets you create simple off-screen renderers to draw something into arbitary MTLTextures
• ComputeCommand: this is an experimental class that does a reflection over Metal kernels and lets you assign arguments by name instead of index. This is a subject for improvements.
• BlendingMode: this type contains the enumeration of eight Alloy's built-in blending modes. You can easily setup one of them just by calling setup(blending:) function.

``swift let renderPipelineDescriptor = MTLRenderPipelineDescriptor() renderPipelineDescriptor.colorAttachments[0].setup(blending: .alpha) ``

MTLContext minimal usage example

MTLContext is usually being injected in the class, as you usually do with MTLDevice, you should cache the context and all heavy-weighted objects so you can reuse them lates, i.e.:

import Alloy

public class BrightnessEncoder {
    public let context: MTLContext
    fileprivate let pipelineState: MTLComputePipelineState

    /**
     * This variable controls the brightness factor. Should be in range of -1.0...1.0
     */
    public var intensity: Float = 1.0

    public init(context: MTLContext) {
        self.context = context

        guard let lib = context.shaderLibrary(for: BrightnessEncoder.self),
              let state = try? lib.computePipelineState(function: "brightness")
        else { fatalError("Error during shader loading") }

        self.pipelineState = state
    }

    public func encode(input: MTLTexture,
                       in commandBuffer: MTLCommandBuffer) {
        commandBuffer.compute { encoder in
            encoder.set(textures: [input])
            encoder.set(self.intensity, at: 0)

            encoder.dispatch2d(state: self.pipelineState,
                               covering: input.size)
        }
    }

}

Note how simple it is to kick off a kernel with Alloy, no more tedious thredgroup size calculations, multiple encoder initialization with balancing .endEncoding() calls.

Then somewhere else you just do

context.scheduleAndWait { buffer in
    self.brightnessEncoder.intensity = sender.floatValue
    self.brightnessEncoder.encode(input: texture,
                                  in: buffer)

    // For Mac applications
    if case .managed = texture.storageMode {
        buffer.blit { encoder in
            encoder.synchronize(resource: texture)
        }
    }
}

With this approach you can easily stack and build your GPU pipeline layers, group blit, compute and render command encodings with Swift closures, while maintaing full flexibility of Metal API.

Installation

CocoaPods

CocoaPods is a dependency manager for Cocoa projects. For usage and installation instructions, visit their website. To integrate Alloy into your Xcode project using CocoaPods, specify it in your Podfile:

# Optionally add version, i.e. '~> 0.9.0'
pod 'Alloy'

License

MIT

Package Metadata

Repository: s1ddok/alloy

Default branch: master

README: README.md