107 lines
3.2 KiB
Swift
107 lines
3.2 KiB
Swift
//
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// Algorithms.swift
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// Terrain2
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//
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// Created by Eryn Wells on 11/4/18.
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// Copyright © 2018 Eryn Wells. All rights reserved.
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//
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import Foundation
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import Metal
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import os
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let Log = OSLog(subsystem: "me.erynwells.Terrain2.Algorithms", category: "DiamondSquare")
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enum KernelError: Error {
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case badFunction
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case badSize
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case textureCreationFailed
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}
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protocol TerrainGenerator {
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var name: String { get }
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var needsGPU: Bool { get }
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var outTexture: MTLTexture { get }
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func encode(in encoder: MTLComputeCommandEncoder)
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func render(progress: Progress) -> [Float]
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}
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class Kernel {
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class var textureSize: MTLSize {
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return MTLSize(width: 512, height: 512, depth: 1)
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}
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class func buildTexture(device: MTLDevice, size: MTLSize) -> MTLTexture? {
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let desc = MTLTextureDescriptor.texture2DDescriptor(pixelFormat: .r32Float, width: size.width, height: size.height, mipmapped: false)
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desc.usage = [.shaderRead, .shaderWrite]
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let tex = device.makeTexture(descriptor: desc)
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return tex
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}
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let pipeline: MTLComputePipelineState
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let textures: [MTLTexture]
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let uniformBuffer: MTLBuffer?
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var outTexture: MTLTexture {
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return textures[textureIndexes.out]
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}
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private(set) var textureIndexes: (`in`: Int, out: Int) = (in: 0, out: 1)
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init(device: MTLDevice, library: MTLLibrary, functionName: String, uniformBuffer: MTLBuffer? = nil) throws {
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guard let computeFunction = library.makeFunction(name: functionName) else {
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throw KernelError.badFunction
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}
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self.pipeline = try device.makeComputePipelineState(function: computeFunction)
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// Create our input and output textures
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var textures = [MTLTexture]()
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for i in 0..<2 {
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guard let tex = Kernel.buildTexture(device: device, size: type(of: self).textureSize) else {
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print("Couldn't create heights texture i=\(i)")
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throw KernelError.textureCreationFailed
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}
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textures.append(tex)
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}
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self.textures = textures
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self.uniformBuffer = uniformBuffer
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}
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func encode(in encoder: MTLComputeCommandEncoder) {
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encoder.setComputePipelineState(pipeline)
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encoder.setTexture(textures[textureIndexes.in], index: textureIndexes.in)
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encoder.setTexture(textures[textureIndexes.out], index: textureIndexes.out)
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encoder.setBuffer(uniformBuffer, offset: 0, index: 0)
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encoder.dispatchThreads(type(of: self).textureSize, threadsPerThreadgroup: MTLSize(width: 8, height: 8, depth: 1))
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}
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}
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/// "Compute" zero for every value of the height map.
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class ZeroAlgorithm: Kernel, TerrainGenerator {
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let name = "Zero"
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let needsGPU: Bool = true
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init?(device: MTLDevice, library: MTLLibrary) {
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do {
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try super.init(device: device, library: library, functionName: "zeroKernel")
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} catch let e {
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print("Couldn't create compute kernel. Error: \(e)")
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return nil
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}
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}
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// MARK: Algorithm
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func render(progress: Progress) -> [Float] {
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return []
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}
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}
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/// Implementation of the Circles algorithm.
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//class CirclesAlgorithm: Algorithm {
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// static let name = "Circles"
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//}
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