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An implementation of the Squirrel3 Noise-based RNG
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| // Based on the GDC 2017 talk "Math for Game Programmers: Noise-Based RNG" | |
| // https://www.youtube.com/watch?v=LWFzPP8ZbdU&ab_channel=GDC | |
| const BIT_NOISE1 = 0xB5297A4D | |
| const BIT_NOISE2 = 0x68E31DA4 | |
| const BIT_NOISE3 = 0x1B56C4E9 | |
| const PRIME1 = 198491317 | |
| const PRIME2 = 6542989 | |
| class Squirrel3 { | |
| constructor() { | |
| } | |
| // get1d(), get2d() and get3d() each return an integer | |
| get1d(x=0, seed=0) { | |
| let mangled = x | |
| mangled *= BIT_NOISE1 | |
| mangled += seed | |
| mangled ^= (mangled >> 8) | |
| mangled += BIT_NOISE2 | |
| mangled ^= (mangled << 8) | |
| mangled *= BIT_NOISE3 | |
| mangled ^= (mangled >> 8) | |
| return mangled | |
| } | |
| get2d(x=0, y=0, seed=0) { | |
| return this.get1d(x + (PRIME1 * y), seed) | |
| } | |
| get3d(x=0, y=0, z=0, seed=0) { | |
| return this.get1d(x + (PRIME1 * y) + (PRIME2 * z), seed) | |
| } | |
| // get1df(), get2df() and get3df() each return a float between 0 and 1 | |
| // (assumes we're working with int32's) | |
| get1df(x=0, seed=0) { | |
| return this.get1d(x, seed) / 0xFFFFFFFF | |
| } | |
| get2df(x=0, y=0, seed=0) { | |
| return this.get2d(x, y, seed) / 0xFFFFFFFF | |
| } | |
| get3df(x=0, y=0, z=0, seed=0) { | |
| return this.get3d(x, y, z, seed) / 0xFFFFFFFF | |
| } | |
| } |
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