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Complete migrating the algorithm implementation to the Algorithm object

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This commit is contained in:
Eryn Wells 2018-11-10 16:03:53 -05:00
parent e50a36f7d1
commit dce01100cc
1 changed files with 46 additions and 50 deletions
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96
Terrain2/Algorithms.swift
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@ -129,6 +129,15 @@ public class DiamondSquareAlgorithm: TerrainGenerator {
public struct Point {
let x: Int
let y: Int
init() {
self.init(x: 0, y: 0)
}
init(x: Int, y: Int) {
self.x = x
self.y = y
}
}
public struct Size {
@ -223,10 +232,33 @@ public class DiamondSquareAlgorithm: TerrainGenerator {
}
/// Run the algorithm and return the genreated height map.
// func render() -> [Float] {
// var heightMap = [Float](repeating: 0, count: grid.size.w * grid.size.h)
// return heightMap
// }
func render() -> [Float] {
var heightMap = [Float](repeating: 0, count: grid.size.w * grid.size.h)
// 0. Set the corners to initial values if they haven't been set yet.
for p in grid.corners {
let idx = convert(pointToIndex: p)
heightMap[idx] = Float.random(in: 0...1)
}
grid.breadthFirstSearch { (box: Box) in
// 1. Diamond step. Find the midpoint of the square defined by `box` and set its value.
let midpoint = box.midpoint
let cornerValues = box.corners.map { heightMap[self.convert(pointToIndex: $0)] }
let midpointValue = Float.random(in: 0...1) + self.average(ofPoints: cornerValues)
heightMap[convert(pointToIndex: midpoint)] = midpointValue
// 2. Square step. For each of the side midpoints of this box, compute its value.
for pt in box.sideMidpoints {
let corners = diamondCorners(forPoint: pt, diamondSize: box.size)
let cornerValues = corners.map { heightMap[self.convert(pointToIndex: $0)] }
let ptValue = Float.random(in: 0...1) + self.average(ofPoints: cornerValues)
heightMap[convert(pointToIndex: pt)] = ptValue
}
}
return heightMap
}
/// Find our diamond's corners, wrapping around the grid if needed.
func diamondCorners(forPoint pt: Point, diamondSize: Size) -> [Point] {
@ -250,6 +282,11 @@ public class DiamondSquareAlgorithm: TerrainGenerator {
}
}
func average(ofPoints pts: [Float]) -> Float {
let scale: Float = 1.0 / Float(pts.count)
return scale * pts.reduce(0) { return $0 + $1 }
}
func convert(pointToIndex pt: Point) -> Int {
return pt.y * grid.size.w + pt.x
}
@ -262,6 +299,7 @@ public class DiamondSquareAlgorithm: TerrainGenerator {
return MTLSize(width: 513, height: 513, depth: 1)
}
var algorithm: Algorithm
let texture: MTLTexture
let textureSemaphore = DispatchSemaphore(value: 1)
@ -275,55 +313,13 @@ public class DiamondSquareAlgorithm: TerrainGenerator {
return nil
}
texture = tex
algorithm = Algorithm(grid: Box(origin: Point(), size: Size(w: DiamondSquareAlgorithm.textureSize.width, h: DiamondSquareAlgorithm.textureSize.height)))
}
func render() {
let size = DiamondSquareAlgorithm.textureSize
func ptToIndex(_ pt: Point) -> Int {
return pt.y * size.width + pt.x
}
var heightMap = [Float](repeating: 0, count: size.width * size.height)
// 0. Set the corners to initial values if they haven't been set yet.
let box = Box(origin: Point(x: 0, y: 0), size: Size(w: size.width, h: size.height))
for p in box.corners {
let idx = ptToIndex(p)
if heightMap[idx] == 0.0 {
heightMap[idx] = Float.random(in: 0...1)
}
}
box.breadthFirstSearch { (box: Box) in
let halfSize = (w: box.size.w / 2 + 1, h: box.size.h / 2 + 1)
// 1. Diamond. Average the corners, add a random value. Set the midpoint.
let midpoint = box.midpoint
let cornerAverage = Float.random(in: 0...1) + 0.25 * box.corners.reduce(0.0) { (acc, pt) -> Float in
let index = ptToIndex(pt)
let value = heightMap[index]
return acc + value
}
let midptIdx = ptToIndex(midpoint)
heightMap[midptIdx] = cornerAverage
// 2. Square. Find the midpoints of the sides of this box. These four points are the origins of the new subdivided boxes.
for p in box.sideMidpoints {
// TODO.
let diamondCorners = [Point]()
let idx = ptToIndex(p)
let value = Float.random(in: 0...1) + 0.25 * diamondCorners.reduce(0) { (acc, pt) -> Float in
let idx = ptToIndex(pt)
let value = heightMap[idx]
return acc + value
}
heightMap[idx] = value
}
}
let region = MTLRegion(origin: MTLOrigin(), size: size)
let heightMap = algorithm.render()
let region = MTLRegion(origin: MTLOrigin(), size: DiamondSquareAlgorithm.textureSize)
texture.replace(region: region, mipmapLevel: 0, withBytes: heightMap, bytesPerRow: MemoryLayout<Float>.stride * size.width)
}