python Perlin Noise

perlin.py

class Perlin (object):
    def __init__(self, seed=0):
        self.seed = seed
        self.hash = [208,34,231,213,32,248,233,56,161,78,24,140,71,48,140,254,245,255,247,247,40,
                     185,248,251,245,28,124,204,204,76,36,1,107,28,234,163,202,224,245,128,167,204,
                     9,92,217,54,239,174,173,102,193,189,190,121,100,108,167,44,43,77,180,204,8,81,
                     70,223,11,38,24,254,210,210,177,32,81,195,243,125,8,169,112,32,97,53,195,13,
                     203,9,47,104,125,117,114,124,165,203,181,235,193,206,70,180,174,0,167,181,41,
                     164,30,116,127,198,245,146,87,224,149,206,57,4,192,210,65,210,129,240,178,105,
                     228,108,245,148,140,40,35,195,38,58,65,207,215,253,65,85,208,76,62,3,237,55,89,
                     232,50,217,64,244,157,199,121,252,90,17,212,203,149,152,140,187,234,177,73,174,
                     193,100,192,143,97,53,145,135,19,103,13,90,135,151,199,91,239,247,33,39,145,
                     101,120,99,3,186,86,99,41,237,203,111,79,220,135,158,42,30,154,120,67,87,167,
                     135,176,183,191,253,115,184,21,233,58,129,233,142,39,128,211,118,137,139,255,
                     114,20,218,113,154,27,127,246,250,1,8,198,250,209,92,222,173,21,88,102,219]

    def _noise2(self, x, y):
        tmp = self.hash[int(y + self.seed) % 256]
        return self.hash[int(tmp + x) % 256]

    def _lin_inter(self, x, y, s):
        return x + s * (y-x)

    def _smooth_inter(self, x, y, s):
        return self._lin_inter(x, y, s * s * (3-2*s))
    
    def _noise2d(self, x, y):
        x_int = x
        y_int = y
        x_frac = x - x_int
        y_frac = y - y_int
        s = self._noise2(x_int, y_int)
        t = self._noise2(x_int+1, y_int)
        u = self._noise2(x_int, y_int+1)
        v = self._noise2(x_int+1, y_int+1)
        low = self._smooth_inter(s, t, x_frac)
        high = self._smooth_inter(u, v, x_frac)
        return self._smooth_inter(low, high, y_frac)

    def perlin2d(self, x, y, freq, depth):
        xa = x*freq
        ya = y*freq
        amp = 1.0
        fin = 0
        div = 0.0

        for i in range(depth):
            div += 256 * amp
            fin += self._noise2d(xa, ya) * amp
            amp /= 2
            xa *= 2
            ya *= 2

        return fin/div


if __name__ == '__main__':
    per = Perlin()
    for y in range(32):
        for x in range(32):            
            print per.perlin2d(x, y, 0.1, 4)