115 lines
4.4 KiB
GLSL
115 lines
4.4 KiB
GLSL
int[512] permutations = {151,160,137,91,90,15,
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131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
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190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
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88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
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77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
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102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
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135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
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5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
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223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
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129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
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251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
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49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
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138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
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151,160,137,91,90,15,
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131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
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190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
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88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
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77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
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102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
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135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
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5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
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223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
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129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
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251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
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49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
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138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
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};
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float grad(int hash, vec3 pos) {
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switch (hash & 0xF) {
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case 0x0: return pos.x + pos.y;
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case 0x1: return -pos.x + pos.y;
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case 0x2: return pos.x - pos.y;
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case 0x3: return -pos.x - pos.y;
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case 0x4: return pos.x + pos.z;
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case 0x5: return -pos.x + pos.z;
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case 0x6: return pos.x - pos.z;
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case 0x7: return -pos.x - pos.z;
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case 0x8: return pos.y + pos.z;
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case 0x9: return -pos.y + pos.z;
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case 0xA: return pos.y - pos.z;
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case 0xB: return -pos.y - pos.z;
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case 0xC: return pos.y + pos.x;
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case 0xD: return -pos.y + pos.z;
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case 0xE: return pos.y - pos.x;
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case 0xF: return -pos.y - pos.z;
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default: return 0.0;
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}
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}
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int hash(ivec3 pos) {
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return permutations[pos.z + permutations[pos.y + permutations[pos.x]]];
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}
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float fade(float t) {
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return t * t * t * (t * (6.0 * t - 15.0) + 10.0);
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}
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float singlePerlin(int seed, vec3 pos) {
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ivec3 posInt = ivec3(floor(pos)) + seed;
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posInt.x &= 255;
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posInt.y &= 255;
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posInt.z &= 255;
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vec3 posDec = fract(pos);
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float g0 = grad(hash(posInt), posDec);
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float g1 = grad(hash(posInt + ivec3(1, 0, 0)), posDec - vec3(1.0, 0.0, 0.0));
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float g2 = grad(hash(posInt + ivec3(0, 1, 0)), posDec - vec3(0.0, 1.0, 0.0));
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float g3 = grad(hash(posInt + ivec3(1, 1, 0)), posDec - vec3(1.0, 1.0, 0.0));
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float g4 = grad(hash(posInt + ivec3(0, 0, 1)), posDec - vec3(0.0, 0.0, 1.0));
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float g5 = grad(hash(posInt + ivec3(1, 0, 1)), posDec - vec3(1.0, 0.0, 1.0));
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float g6 = grad(hash(posInt + ivec3(0, 1, 1)), posDec - vec3(0.0, 1.0, 1.0));
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float g7 = grad(hash(posInt + ivec3(1, 1, 1)), posDec - vec3(1.0, 1.0, 1.0));
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float u = fade(posDec.x);
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float v = fade(posDec.y);
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float w = fade(posDec.z);
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float x1 = mix(g0, g1, u);
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float x2 = mix(g2, g3, u);
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float x3 = mix(g4, g5, u);
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float x4 = mix(g6, g7, u);
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float y1 = mix(x1, x2, v);
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float y2 = mix(x3, x4, v);
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return mix(y1, y2, w);
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}
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float perlin(int seed, int octaves, float persistence, vec3 pos)
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{
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float amplitude = 1;
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float frequency = 1;
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float maxValue = 0;
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float total = 0;
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for (int i = 0; i < octaves; i++) {
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total += singlePerlin(seed, pos * frequency) * amplitude;
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maxValue += amplitude;
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amplitude *= persistence;
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frequency *= 2;
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}
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return total / maxValue;
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}
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float singleRidged(int seed, vec3 pos) {
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return 1 - abs(singlePerlin(seed, pos) - 0.5) * 2;
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}
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