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| 1 | +// Based on https://github.com/stegu/webgl-noise/blob/22434e04d7753f7e949e8d724ab3da2864c17a0f/src/noise3D.glsl |
| 2 | +// MIT licensed, adapted for p5.strands |
| 3 | + |
| 4 | +vec3 mod289(vec3 x) { |
| 5 | + return x - floor(x * (1.0 / 289.0)) * 289.0; |
| 6 | +} |
| 7 | + |
| 8 | +vec4 mod289(vec4 x) { |
| 9 | + return x - floor(x * (1.0 / 289.0)) * 289.0; |
| 10 | +} |
| 11 | + |
| 12 | +vec4 permute(vec4 x) { |
| 13 | + return mod289(((x*34.0)+10.0)*x); |
| 14 | +} |
| 15 | + |
| 16 | +vec4 taylorInvSqrt(vec4 r) |
| 17 | +{ |
| 18 | + return 1.79284291400159 - 0.85373472095314 * r; |
| 19 | +} |
| 20 | + |
| 21 | +float baseNoise(vec3 v) |
| 22 | +{ |
| 23 | + const vec2 C = vec2(1.0/6.0, 1.0/3.0) ; |
| 24 | + const vec4 D = vec4(0.0, 0.5, 1.0, 2.0); |
| 25 | + |
| 26 | + // First corner |
| 27 | + vec3 i = floor(v + dot(v, C.yyy) ); |
| 28 | + vec3 x0 = v - i + dot(i, C.xxx) ; |
| 29 | + |
| 30 | + // Other corners |
| 31 | + vec3 g = step(x0.yzx, x0.xyz); |
| 32 | + vec3 l = 1.0 - g; |
| 33 | + vec3 i1 = min( g.xyz, l.zxy ); |
| 34 | + vec3 i2 = max( g.xyz, l.zxy ); |
| 35 | + |
| 36 | + // x0 = x0 - 0.0 + 0.0 * C.xxx; |
| 37 | + // x1 = x0 - i1 + 1.0 * C.xxx; |
| 38 | + // x2 = x0 - i2 + 2.0 * C.xxx; |
| 39 | + // x3 = x0 - 1.0 + 3.0 * C.xxx; |
| 40 | + vec3 x1 = x0 - i1 + C.xxx; |
| 41 | + vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y |
| 42 | + vec3 x3 = x0 - D.yyy; // -1.0+3.0*C.x = -0.5 = -D.y |
| 43 | + |
| 44 | + // Permutations |
| 45 | + i = mod289(i); |
| 46 | + vec4 p = permute( permute( permute( |
| 47 | + i.z + vec4(0.0, i1.z, i2.z, 1.0 )) |
| 48 | + + i.y + vec4(0.0, i1.y, i2.y, 1.0 )) |
| 49 | + + i.x + vec4(0.0, i1.x, i2.x, 1.0 )); |
| 50 | + |
| 51 | + // Gradients: 7x7 points over a square, mapped onto an octahedron. |
| 52 | + // The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294) |
| 53 | + float n_ = 0.142857142857; // 1.0/7.0 |
| 54 | + vec3 ns = n_ * D.wyz - D.xzx; |
| 55 | + |
| 56 | + vec4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p,7*7) |
| 57 | + |
| 58 | + vec4 x_ = floor(j * ns.z); |
| 59 | + vec4 y_ = floor(j - 7.0 * x_ ); // mod(j,N) |
| 60 | + |
| 61 | + vec4 x = x_ *ns.x + ns.yyyy; |
| 62 | + vec4 y = y_ *ns.x + ns.yyyy; |
| 63 | + vec4 h = 1.0 - abs(x) - abs(y); |
| 64 | + |
| 65 | + vec4 b0 = vec4( x.xy, y.xy ); |
| 66 | + vec4 b1 = vec4( x.zw, y.zw ); |
| 67 | + |
| 68 | + //vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0; |
| 69 | + //vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0; |
| 70 | + vec4 s0 = floor(b0)*2.0 + 1.0; |
| 71 | + vec4 s1 = floor(b1)*2.0 + 1.0; |
| 72 | + vec4 sh = -step(h, vec4(0.0)); |
| 73 | + |
| 74 | + vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ; |
| 75 | + vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ; |
| 76 | + |
| 77 | + vec3 p0 = vec3(a0.xy,h.x); |
| 78 | + vec3 p1 = vec3(a0.zw,h.y); |
| 79 | + vec3 p2 = vec3(a1.xy,h.z); |
| 80 | + vec3 p3 = vec3(a1.zw,h.w); |
| 81 | + |
| 82 | + //Normalise gradients |
| 83 | + vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3))); |
| 84 | + p0 *= norm.x; |
| 85 | + p1 *= norm.y; |
| 86 | + p2 *= norm.z; |
| 87 | + p3 *= norm.w; |
| 88 | + |
| 89 | + // Mix final noise value |
| 90 | + vec4 m = max(0.5 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0); |
| 91 | + m = m * m; |
| 92 | + return 105.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1), |
| 93 | + dot(p2,x2), dot(p3,x3) ) ); |
| 94 | +} |
| 95 | + |
| 96 | +float noise(vec3 st) { |
| 97 | + float result = 0.0; |
| 98 | + float amplitude = 1.0; |
| 99 | + float frequency = 1.0; |
| 100 | + |
| 101 | + for (int i = 0; i < 4; i++) { |
| 102 | + result += amplitude * baseNoise(st * frequency); |
| 103 | + frequency *= 2.0; |
| 104 | + amplitude *= 0.5; |
| 105 | + } |
| 106 | + |
| 107 | + return result; |
| 108 | +} |
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