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Reduce randomness spread every time Diamond-Squre reduces the grid size

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Eryn Wells 2018-11-23 13:18:05 -07:00
parent ac7ae15ceb
commit 240499ced8
1 changed files with 12 additions and 4 deletions
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16
Terrain2/Algorithms/DiamondSquare.swift
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@ -124,7 +124,7 @@ public class DiamondSquareGenerator: TerrainGenerator {
} }
} }
private var randomRange = Float(0)...Float(1) private var randomRange = Float(-1)...Float(1)
init(grid: Box) { init(grid: Box) {
// TODO: Assert log2(w) and log2(h) are integral values. // TODO: Assert log2(w) and log2(h) are integral values.
@ -137,12 +137,14 @@ public class DiamondSquareGenerator: TerrainGenerator {
os_signpost(.begin, log: Log, name: "DiamondSquare.render") os_signpost(.begin, log: Log, name: "DiamondSquare.render")
var boxSize = grid.size
var spread = randomRange
var heightMap = [Float](repeating: 0, count: grid.size.w * grid.size.h) 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. // 0. Set the corners to initial values if they haven't been set yet.
for p in grid.corners { for p in grid.corners {
let idx = convert(pointToIndex: p) let idx = convert(pointToIndex: p)
heightMap[idx] = Float.random(in: randomRange) heightMap[idx] = Float.random(in: spread)
} }
renderProgress.completedUnitCount += 1 renderProgress.completedUnitCount += 1
@ -153,7 +155,7 @@ public class DiamondSquareGenerator: TerrainGenerator {
let idx = self.convert(pointToIndex: pt) let idx = self.convert(pointToIndex: pt)
return heightMap[idx] return heightMap[idx]
} }
let midpointValue = Float.random(in: randomRange) + self.average(ofPoints: cornerValues) let midpointValue = Float.random(in: spread) + self.average(ofPoints: cornerValues)
heightMap[convert(pointToIndex: midpoint)] = midpointValue heightMap[convert(pointToIndex: midpoint)] = midpointValue
// 2. Square step. For each of the side midpoints of this box, compute its value. // 2. Square step. For each of the side midpoints of this box, compute its value.
@ -163,9 +165,15 @@ public class DiamondSquareGenerator: TerrainGenerator {
let idx = self.convert(pointToIndex: pt) let idx = self.convert(pointToIndex: pt)
return heightMap[idx] return heightMap[idx]
} }
let ptValue = Float.random(in: randomRange) + self.average(ofPoints: cornerValues) let ptValue = Float.random(in: spread) + self.average(ofPoints: cornerValues)
heightMap[convert(pointToIndex: pt)] = ptValue heightMap[convert(pointToIndex: pt)] = ptValue
} }
if box.size != boxSize {
// Reduce the spread as we recurse down to smaller squares.
spread = -(spread.lowerBound * 0.5)...(spread.upperBound * 0.5)
boxSize = box.size
}
} }
os_signpost(.end, log: Log, name: "DiamondSquare.render") os_signpost(.end, log: Log, name: "DiamondSquare.render")