CrunkLord420
72 lines
2.1 KiB
HolyC
72 lines
2.1 KiB
HolyC
#ifndef PERLIN_HC
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#define PERLIN_HC
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#define PERLIN_SEED 1985
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U8 PerlinHash[256] = {
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208,34,231,213,32,248,233,56,161,78,24,140,71,48,140,254,245,255,247,247,40,
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185,248,251,245,28,124,204,204,76,36,1,107,28,234,163,202,224,245,128,167,204,
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9,92,217,54,239,174,173,102,193,189,190,121,100,108,167,44,43,77,180,204,8,81,
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70,223,11,38,24,254,210,210,177,32,81,195,243,125,8,169,112,32,97,53,195,13,
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203,9,47,104,125,117,114,124,165,203,181,235,193,206,70,180,174,0,167,181,41,
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164,30,116,127,198,245,146,87,224,149,206,57,4,192,210,65,210,129,240,178,105,
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228,108,245,148,140,40,35,195,38,58,65,207,215,253,65,85,208,76,62,3,237,55,89,
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232,50,217,64,244,157,199,121,252,90,17,212,203,149,152,140,187,234,177,73,174,
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193,100,192,143,97,53,145,135,19,103,13,90,135,151,199,91,239,247,33,39,145,
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101,120,99,3,186,86,99,41,237,203,111,79,220,135,158,42,30,154,120,67,87,167,
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135,176,183,191,253,115,184,21,233,58,129,233,142,39,128,211,118,137,139,255,
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114,20,218,113,154,27,127,246,250,1,8,198,250,209,92,222,173,21,88,102,219
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};
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I64 Noise2(I64 x, I64 y) {
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I64 yindex = (y + PERLIN_SEED) % 256;
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if (yindex < 0)
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yindex += 256;
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I64 xindex = (PerlinHash[yindex] + x) % 256;
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if (xindex < 0)
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xindex += 256;
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I64 result = PerlinHash[xindex];
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return result;
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}
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F64 lin_inter(F64 x, F64 y, F64 s) {
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return x + s * (y-x);
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}
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F64 smooth_inter(F64 x, F64 y, F64 s) {
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return lin_inter( x, y, s * s * (3-2*s) );
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}
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F64 noise2d(F64 x, F64 y) {
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I64 x_int = Floor(x);
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I64 y_int = Floor(y);
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F64 x_frac = x - x_int;
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F64 y_frac = y - y_int;
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I64 s = Noise2(x_int, y_int);
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I64 t = Noise2(x_int+1, y_int);
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I64 u = Noise2(x_int, y_int+1);
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I64 v = Noise2(x_int+1, y_int+1);
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F64 low = smooth_inter(s, t, x_frac);
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F64 high = smooth_inter(u, v, x_frac);
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F64 result = smooth_inter(low, high, y_frac);
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return result;
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}
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F64 Perlin_Get2d(F64 x, F64 y, F64 freq, I64 depth) {
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F64 xa = x*freq;
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F64 ya = y*freq;
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F64 amp = 1.0;
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F64 fin = 0;
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F64 div = 0.0;
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I64 i;
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for (i=0; i<depth; i++) {
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div += 256 * amp;
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fin += noise2d( xa, ya ) * amp;
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amp /= 2;
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xa *= 2;
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ya *= 2;
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}
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return fin/div;
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}
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#endif |