mirror of
https://github.com/Refactorio/RedMew.git
synced 2024-12-14 10:13:13 +02:00
128 lines
4.2 KiB
Lua
128 lines
4.2 KiB
Lua
--[[
|
|
Implemented as described here:
|
|
http://flafla2.github.io/2014/08/09/perlinnoise.html
|
|
]]--
|
|
|
|
perlin = {}
|
|
perlin.p = {}
|
|
|
|
-- Hash lookup table as defined by Ken Perlin
|
|
-- This is a randomly arranged array of all numbers from 0-255 inclusive
|
|
local 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
|
|
}
|
|
|
|
-- p is used to hash unit cube coordinates to [0, 255]
|
|
for i=0,255 do
|
|
-- Convert to 0 based index table
|
|
perlin.p[i] = permutation[i+1]
|
|
-- Repeat the array to avoid buffer overflow in hash function
|
|
perlin.p[i+256] = permutation[i+1]
|
|
end
|
|
|
|
-- Return range: [-1, 1]
|
|
function perlin:noise(x, y, z)
|
|
y = y or 0
|
|
z = z or 0
|
|
|
|
-- Calculate the "unit cube" that the point asked will be located in
|
|
local xi = bit32.band(math.floor(x),255)
|
|
local yi = bit32.band(math.floor(y),255)
|
|
local zi = bit32.band(math.floor(z),255)
|
|
|
|
-- Next we calculate the location (from 0 to 1) in that cube
|
|
x = x - math.floor(x)
|
|
y = y - math.floor(y)
|
|
z = z - math.floor(z)
|
|
|
|
-- We also fade the location to smooth the result
|
|
local u = self.fade(x)
|
|
local v = self.fade(y)
|
|
local w = self.fade(z)
|
|
|
|
-- Hash all 8 unit cube coordinates surrounding input coordinate
|
|
local p = self.p
|
|
local A, AA, AB, AAA, ABA, AAB, ABB, B, BA, BB, BAA, BBA, BAB, BBB
|
|
A = p[xi ] + yi
|
|
AA = p[A ] + zi
|
|
AB = p[A+1 ] + zi
|
|
AAA = p[ AA ]
|
|
ABA = p[ AB ]
|
|
AAB = p[ AA+1 ]
|
|
ABB = p[ AB+1 ]
|
|
|
|
B = p[xi+1] + yi
|
|
BA = p[B ] + zi
|
|
BB = p[B+1 ] + zi
|
|
BAA = p[ BA ]
|
|
BBA = p[ BB ]
|
|
BAB = p[ BA+1 ]
|
|
BBB = p[ BB+1 ]
|
|
|
|
-- Take the weighted average between all 8 unit cube coordinates
|
|
return self.lerp(w,
|
|
self.lerp(v,
|
|
self.lerp(u,
|
|
self:grad(AAA,x,y,z),
|
|
self:grad(BAA,x-1,y,z)
|
|
),
|
|
self.lerp(u,
|
|
self:grad(ABA,x,y-1,z),
|
|
self:grad(BBA,x-1,y-1,z)
|
|
)
|
|
),
|
|
self.lerp(v,
|
|
self.lerp(u,
|
|
self:grad(AAB,x,y,z-1), self:grad(BAB,x-1,y,z-1)
|
|
),
|
|
self.lerp(u,
|
|
self:grad(ABB,x,y-1,z-1), self:grad(BBB,x-1,y-1,z-1)
|
|
)
|
|
)
|
|
)
|
|
end
|
|
|
|
-- Gradient function finds dot product between pseudorandom gradient vector
|
|
-- and the vector from input coordinate to a unit cube vertex
|
|
perlin.dot_product = {
|
|
[0x0]=function(x,y,z) return x + y end,
|
|
[0x1]=function(x,y,z) return -x + y end,
|
|
[0x2]=function(x,y,z) return x - y end,
|
|
[0x3]=function(x,y,z) return -x - y end,
|
|
[0x4]=function(x,y,z) return x + z end,
|
|
[0x5]=function(x,y,z) return -x + z end,
|
|
[0x6]=function(x,y,z) return x - z end,
|
|
[0x7]=function(x,y,z) return -x - z end,
|
|
[0x8]=function(x,y,z) return y + z end,
|
|
[0x9]=function(x,y,z) return -y + z end,
|
|
[0xA]=function(x,y,z) return y - z end,
|
|
[0xB]=function(x,y,z) return -y - z end,
|
|
[0xC]=function(x,y,z) return y + x end,
|
|
[0xD]=function(x,y,z) return -y + z end,
|
|
[0xE]=function(x,y,z) return y - x end,
|
|
[0xF]=function(x,y,z) return -y - z end
|
|
}
|
|
function perlin:grad(hash, x, y, z)
|
|
return self.dot_product[bit32.band(hash,0xF)](x,y,z)
|
|
end
|
|
|
|
-- Fade function is used to smooth final output
|
|
function perlin.fade(t)
|
|
return t * t * t * (t * (t * 6 - 15) + 10)
|
|
end
|
|
|
|
function perlin.lerp(t, a, b)
|
|
return a + t * (b - a)
|
|
end
|