67 lines
2.9 KiB
Text
67 lines
2.9 KiB
Text
local permutation <const> = {
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151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225,
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140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148,
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247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32,
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57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175,
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74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122,
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60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54,
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65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169,
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200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64,
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52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212,
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207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213,
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119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
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129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104,
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218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241,
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81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,
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184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93,
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222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180
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}
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local p = range(0, 511):map(|i| -> i < 256 ? permutation[i + 1] : permutation[i - 255])
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local fade = |t| -> t * t * t * (t * (t * 6 - 15) + 10)
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local lerp = |t, a, b| -> a + t * (b - a)
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local function grad(hash, x, y, z)
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-- Convert low 4 bits of hash code into 12 gradient directions.
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local h = hash & 15
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local u = (h < 8) ? x : y
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local v = (h < 4) ? y : (h == 12 or h == 14) ? x : z
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return (((h & 1) == 0) ? u : -u) + (((h & 2) == 0) ? v : -v)
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end
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local function noise(x, y, z)
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-- Find unit cube that contains point.
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local xi = math.floor(x) & 255
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local yi = math.floor(y) & 255
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local zi = math.floor(z) & 255
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-- Find relative x, y, z of point in cube.
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local xx = x - math.floor(x)
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local yy = y - math.floor(y)
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local zz = z - math.floor(z)
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-- Compute fade curves for each of xx, yy, zz.
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local u = fade(xx)
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local v = fade(yy)
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local w = fade(zz)
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-- Hash co-ordinates of the 8 cube corners
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-- and add blended results from 8 corners of cube.
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local a = p[xi + 1] + yi
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local aa = p[a + 1] + zi
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local ab = p[a + 2] + zi
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local b = p[xi + 2] + yi
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local ba = p[b + 1] + zi
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local bb = p[b + 2] + zi
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return lerp(w,
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lerp(v, lerp(u, grad(p[aa + 1], xx, yy, zz), grad(p[ba + 1], xx - 1, yy, zz)),
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lerp(u, grad(p[ab + 1], xx, yy - 1, zz), grad(p[bb + 1], xx - 1, yy - 1, zz))),
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lerp(v, lerp(u, grad(p[aa + 2], xx, yy, zz - 1), grad(p[ba + 2], xx - 1, yy, zz - 1)),
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lerp(u, grad(p[ab + 2], xx, yy - 1, zz - 1), grad(p[bb + 2], xx - 1, yy - 1, zz - 1)))
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)
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end
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print(noise(3.14, 42, 7))
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