122 lines
3.8 KiB
Swift
122 lines
3.8 KiB
Swift
//
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// MarchingSquares.swift
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// Metaballs
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//
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// Created by Eryn Wells on 10/11/18.
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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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class MarchingSquares {
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private var field: Field
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private var sampleGridSize = Size(16)
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private var semaphore: DispatchSemaphore
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/// Samples of the field's current state.
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private(set) var samplesBuffer: MTLBuffer?
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/// Indexes of geometry to render.
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private(set) var indexes: MTLTexture?
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private(set) var gridGeometry: MTLBuffer?
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private var xSamples: Int {
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return Int(field.size.x / sampleGridSize.x)
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}
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private var ySamples: Int {
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return Int(field.size.y / sampleGridSize.y)
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}
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private var lastSamplesCount = 0
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var samplesCount: Int {
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return xSamples * ySamples
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}
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init(field: Field) {
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self.field = field
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semaphore = DispatchSemaphore(value: 1)
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}
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func setupMetal(withDevice device: MTLDevice) {
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// let samplesDesc = MTLTextureDescriptor()
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// samplesDesc.textureType = .type2D
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// samplesDesc.width = xSamples
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// samplesDesc.height = ySamples
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// samplesDesc.pixelFormat = .r32Float
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// samples = device.makeTexture(descriptor: samplesDesc)
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//
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// let indexesDesc = MTLTextureDescriptor()
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// indexesDesc.textureType = .type2D
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// indexesDesc.width = xSamples - 1
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// indexesDesc.height = ySamples - 1
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// indexesDesc.pixelFormat = .a8Unorm
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// indexes = device.makeTexture(descriptor: indexesDesc)
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}
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func fieldDidResize() {
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guard let device = gridGeometry?.device else {
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return
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}
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populateGrid(withDevice: device)
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populateSamples(withDevice: device)
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lastSamplesCount = samplesCount
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}
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func populateGrid(withDevice device: MTLDevice) {
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guard lastSamplesCount != samplesCount else {
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return
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}
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print("Populating grid with (\(xSamples), \(ySamples)) samples")
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let gridSizeX = Float(sampleGridSize.x)
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let gridSizeY = Float(sampleGridSize.y)
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var grid = [Rect]()
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grid.reserveCapacity(samplesCount)
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for y in 0..<ySamples {
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for x in 0..<xSamples {
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let transform = Matrix4x4.translation(dx: Float(x) * gridSizeX, dy: Float(y) * gridSizeY, dz: 0.0) * Matrix4x4.scale(x: gridSizeX, y: gridSizeY, z: 1)
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let color = Float4(r: 0, g: 1, b: 0, a: 1)
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let rect = Rect(transform: transform, color: color)
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grid.append(rect)
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}
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}
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if let buffer = device.makeBuffer(length: MemoryLayout<Rect>.stride * samplesCount, options: .storageModeShared) {
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memcpy(buffer.contents(), grid, MemoryLayout<Rect>.stride * grid.count)
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gridGeometry = buffer
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} else {
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fatalError("Couldn't create buffer for grid rects")
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}
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}
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func populateSamples(withDevice device: MTLDevice) {
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print("Populating samples buffer with \(samplesCount) values")
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var samples = [Float]()
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samples.reserveCapacity(samplesCount)
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for ys in 0..<ySamples {
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let y = Float(ys * Int(sampleGridSize.y))
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for xs in 0..<xSamples {
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let x = Float(xs * Int(sampleGridSize.x))
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let sample = field.sample(at: Float2(x: x, y: y))
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samples.append(sample)
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}
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}
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let samplesLength = MemoryLayout<Float>.stride * samplesCount
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if let buffer = device.makeBuffer(length: MemoryLayout<Float>.stride * samples.count, options: .storageModeShared) {
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memcpy(buffer.contents(), samples, samplesLength)
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samplesBuffer = buffer
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} else {
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fatalError("Couldn't create buffer for samples")
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}
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}
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}
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