Been looking into terrain generation as an experiment, but don't know how to actually do it.
http://www.google.com/search?q=perlin+noise
Found some code on this page:
http://freespace.virgin.net/hugo.elias/ ... perlin.htm
But I can't figure out how to convert the 2D functions to Lua. There are some methods on there I don't know how to translate to Lua. My first hurdle was 7fffffff. I don't know what that is or how it applies.
I dunno. I have no idea where to begin. Or whether I should try.
Perlin noise generation in Lua/Löve?
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- tentus
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Re: Perlin noise generation in Lua/Löve?
That's a random function he's writing, to generate the points in the line graphs. You can use this to achieve the same thing (If I read it right):Jasoco wrote:But I can't figure out how to convert the 2D functions to Lua. There are some methods on there I don't know how to translate to Lua. My first hurdle was 7fffffff. I don't know what that is or how it applies.
Code: Select all
function intNoise()
return ((math.random() * 2) - 1)
end
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- Jasoco
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Re: Perlin noise generation in Lua/Löve?
I dunno. His noise function receives a variable and bases the returned value on it. I'm more interested in the 2D version also. The 1D version wouldn't be useful for terrain.
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Re: Perlin noise generation in Lua/Löve?
Ah, you're right. Looks like that function takes in a number and returns a random-seeming float between 1 and -1. Interesting.
I've been thinking about doing some perlin stuff recently too, thanks to Shamus Young.
I've been thinking about doing some perlin stuff recently too, thanks to Shamus Young.
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Re: Perlin noise generation in Lua/Löve?
That's hexadecimal (base 16). It's just a different way of writing 2147483647, a prime number. Lua has a random number generator in the math library so you shouldn't have to make your own. Also you'll want to understand the 1D function before trying to grasp 2d because it's the same but applied in two dimensions.Jasoco wrote: My first hurdle was 7fffffff. I don't know what that is or how it applies.
I don't know why you would need several random number generators though. Just alter your seed input slightly but deterministically for each function:
Code: Select all
function random1(val)
math.randomseed(val)
-- get random numbers
end
function random2(val)
math.randomseed(val+1)
-- get random numbers
end
-- etc
- slime
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Re: Perlin noise generation in Lua/Löve?
As seen in this post, there is a fast perlin/simplex noise generator for LuaJIT: http://staffwww.itn.liu.se/~stegu/simpl ... /Noise.lua
Re: Perlin noise generation in Lua/Löve?
I did implement that noise function for the 4KB explosion contest.
They key is that you get the same random value depending on the x- and y-coordinates you are going to write. The tutorial uses that weird noise function, which is fast in C, but not in Lua. I created an image data full of random values where the random value for given x and y can be retrieved by ImageData:getPixel.
The relevant code is in the function value_noise in loader.lua.
They key is that you get the same random value depending on the x- and y-coordinates you are going to write. The tutorial uses that weird noise function, which is fast in C, but not in Lua. I created an image data full of random values where the random value for given x and y can be retrieved by ImageData:getPixel.
The relevant code is in the function value_noise in loader.lua.
Re: Perlin noise generation in Lua/Löve?
That's funny, I just sat down with the intention of experimenting with Perlin noise for a game I want to make. I have a glance at the Löve forums, and see this thread.
Re: Perlin noise generation in Lua/Löve?
This will do the job:
For generating a 2d map you would do something like that:
Where map.dx/dy is the offset and map.scale the zoom factor
Code: Select all
function noise( x, y, z)
local X = math.floor(x % 255)
local Y = math.floor(y % 255)
local Z = math.floor(z % 255)
x = x - math.floor(x)
y = y - math.floor(y)
z = z - math.floor(z)
local u = fade(x)
local v = fade(y)
local w = fade(z)
A = p[X ]+Y
AA = p[A]+Z
AB = p[A+1]+Z
B = p[X+1]+Y
BA = p[B]+Z
BB = p[B+1]+Z
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 )))
)
end
function fade (t)
return t * t * t * (t * (t * 6 - 15) + 10)
end
function lerp(t,a,b)
return a + t * (b - a)
end
function grad(hash,x,y,z)
local h = hash % 16
local u
local v
if (h<8) then u = x else u = y end
if (h<4) then v = y elseif (h==12 or h==14) then v=x else v=z end
local r
if ((h%2) == 0) then r=u else r=-u end
if ((h%4) == 0) then r=r+v else r=r-v end
return r
end
p = {}
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
}
for i=0,255 do
p[i] = permutation[i+1]
p[256+i] = permutation[i+1]
end
Code: Select all
-- generate noise
for x=1,map.sizeX do
for y=1,map.sizeY do
map.elevation[x][y] = noise(x/map.scale + map.dx, y/map.scale + map.dy,0)
end
end
Re: Perlin noise generation in Lua/Löve?
By the way ... here is a little island generator based on my previous code snipplet:
(Press "g" for a new random island)
(Press "g" for a new random island)
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