Pseudorandom number generator for noise

Question

I\'m trying to make the Perlin noise algorithm described at http://freespace.virgin.net/hugo.elias/models/m_perlin.htm using Lua. However, it doesn\'t work properly since Lu

Answer 1

It is easy to make a linear congruential random number generator in Lua. A simple one is Park-Miller

function pmrng (x) return math.fmod(x * 16807, 2147483647) end

This will give you the next random integer [1..2147483646] after x, the seed. Use this integer to make a float by dividing by the modulus, 2147483647 in this case.

prng_seed = 13579
function upmrng () prng_seed = pmrng(prng_seed); return prng_seed / 2147483647 end

To scale this to -1 .. +1 do

upmrng() * 2 - 1