ImprovedNoise.gd

extends Node

#############################################################
# Improved Noise by Ken Perlin
# Ported from: https://mrl.nyu.edu/~perlin/noise/
#------------------------------------------------------------

var p = []
var permutation = [ 151,160,137,91,90,15,
    131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
    190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
    88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
    77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
    102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
    135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
    5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
    223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
    129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
    251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
    49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
    138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180]

func _init():
    for i in range(512):
        p.append(0)

    for i in range(256):
        p[i] = permutation[i]
        p[256+i] = p[i]

func noise(x, y, z): # float params
    # FIND UNIT CUBE THAT CONTAINS POINT.
    var X = int(floor(x)) & 255
    var Y = int(floor(y)) & 255
    var Z = int(floor(z)) & 255

    # FIND RELATIVE X,Y,Z OF POINT IN CUBE.
    x -= floor(x)
    y -= floor(y)
    z -= floor(z)

    # COMPUTE FADE CURVES FOR EACH OF X,Y,Z.
    var u = fade(x)
    var v = fade(y)
    var w = fade(z)

    # HASH COORDINATES OF THE 8 CUBE CORNERS
    var A  = p[X  ] + Y
    var AA = p[A  ] + Z
    var AB = p[A+1] + Z
    var B  = p[X+1] + Y
    var BA = p[B  ] + Z
    var BB = p[B+1] + Z

    # AND ADD BLENDED RESULTS FROM 8 CORNERS OF CUBE
    return lerp_(w, lerp_(v, lerp_(u, grad( p[AA  ], x  , y  , z   ),
                                      grad( p[BA  ], x-1, y  , z   )),
                             lerp_(u, grad( p[AB  ], x  , y-1, z   ),
                                      grad( p[BB  ], x-1, y-1, z   ))),
                    lerp_(v, lerp_(u, grad( p[AA+1], x  , y  , z-1 ),
                                      grad( p[BA+1], x-1, y  , z-1 )),
                             lerp_(u, grad( p[AB+1], x  , y-1, z-1 ),
                                      grad( p[BB+1], x-1, y-1, z-1 ))))

func fade(t): # float
    return t * t * t * (t * (t * 6 - 15) + 10)

func lerp_(t, a, b):
    # Ken Perlin used t (weight) as the first parameter to better organize
    # the blending statement above, I suppose, so a swap is needed here
    # return a + t * (b - a)
    return lerp(a, b, t)

func grad(hash_, x, y, z): # int, floats
    # CONVERT LO 4 BITS OF HASH CODE INTO 12 GRADIENT DIRECTIONS.
    var h = hash_ & 15
    var u = x if h < 8 else y
    var v = y if h < 4 else x if h == 12 or h == 14 else z

    return (u if (h & 1) == 0 else -u) + (v if (h & 2) == 0 else -v)