64 lines
2.1 KiB
Swift
64 lines
2.1 KiB
Swift
//
|
|
// MarchingSquares.swift
|
|
// Metaballs
|
|
//
|
|
// Created by Eryn Wells on 10/11/18.
|
|
// Copyright © 2018 Eryn Wells. All rights reserved.
|
|
//
|
|
|
|
import Foundation
|
|
import Metal
|
|
|
|
class MarchingSquares {
|
|
private var field: Field
|
|
private var sampleGridSize: Size
|
|
|
|
/// Samples of the field's current state.
|
|
private(set) var samples: MTLTexture?
|
|
/// Indexes of geometry to render.
|
|
private(set) var indexes: MTLTexture?
|
|
|
|
init(field: Field) {
|
|
self.field = field
|
|
sampleGridSize = Size(16)
|
|
}
|
|
|
|
func setupMetal(withDevice device: MTLDevice) {
|
|
let xSamples = Int(field.size.x / sampleGridSize.x)
|
|
let ySamples = Int(field.size.y / sampleGridSize.y)
|
|
|
|
let samplesDesc = MTLTextureDescriptor()
|
|
samplesDesc.textureType = .type2D
|
|
samplesDesc.width = xSamples
|
|
samplesDesc.height = ySamples
|
|
samplesDesc.pixelFormat = .depth32Float
|
|
samples = device.makeTexture(descriptor: samplesDesc)
|
|
|
|
let indexesDesc = MTLTextureDescriptor()
|
|
indexesDesc.textureType = .type2D
|
|
indexesDesc.width = xSamples - 1
|
|
indexesDesc.height = ySamples - 1
|
|
indexesDesc.pixelFormat = .a8Unorm
|
|
indexes = device.makeTexture(descriptor: indexesDesc)
|
|
}
|
|
|
|
func sampleField() {
|
|
guard let samples = samples else { return }
|
|
|
|
let xSamples = Int(field.size.x / sampleGridSize.x)
|
|
let ySamples = Int(field.size.y / sampleGridSize.y)
|
|
for xSample in 0..<xSamples {
|
|
let x = Float(xSample * Int(sampleGridSize.x))
|
|
for ySample in 0..<ySamples {
|
|
let y = Float(ySample * Int(sampleGridSize.y))
|
|
let sample = [field.sample(at: Float2(x: x, y: y))]
|
|
|
|
let origin = MTLOrigin(x: xSample, y: ySample, z: 0)
|
|
let size = MTLSize(width: 1, height: 1, depth: 1)
|
|
let region = MTLRegion(origin: origin, size: size)
|
|
let bytesPerRow = samples.width * MemoryLayout<Float>.stride
|
|
samples.replace(region: region, mipmapLevel: 0, withBytes: sample, bytesPerRow: bytesPerRow)
|
|
}
|
|
}
|
|
}
|
|
}
|