Separate noise chunk generator code

src/app/preview/math/NormalNoise.ts

@@ -0,0 +1,35 @@
+import { PerlinNoise } from './PerlinNoise'
+
+export class NormalNoise {
+  private valueFactor: number
+  private first: PerlinNoise
+  private second: PerlinNoise
+
+  constructor(seed: string, firstOctave: number, amplitudes: number[]) {
+    this.first = new PerlinNoise(seed, firstOctave, amplitudes)
+    this.second = new PerlinNoise(seed + 'a', firstOctave, amplitudes)
+
+    let min = +Infinity
+    let max = -Infinity
+    for (let i = 0; i < amplitudes.length; i += 1) {
+      if (amplitudes[i] !== 0) {
+        min = Math.min(min, i)
+        max = Math.max(max, i)
+      }
+    }
+
+    const expectedDeviation = 0.1 * (1 + 1 / (max - min + 1))
+    this.valueFactor = (1/6) / expectedDeviation
+  }
+
+  getValue(x: number, y: number, z: number) {
+    const x2 = x * 1.0181268882175227
+    const y2 = y * 1.0181268882175227
+    const z2 = z * 1.0181268882175227
+    return (this.first.getValue(x, y, z) + this.second.getValue(x2, y2, z2)) * this.valueFactor
+  }
+
+  private wrap(value: number) {
+    return value - Math.floor(value / 3.3554432E7 + 0.5) * 3.3554432E7
+  }
+}