71 lines
No EOL
2.2 KiB
GLSL
71 lines
No EOL
2.2 KiB
GLSL
#version 330
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// Permute
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vec3 permute(vec3 x) { return mod(((x*34.0)+1.0)*x, 289.0); }
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vec4 permute(vec4 x){return mod(((x*34.0)+1.0)*x, 289.0);}
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// Classic Perlin 2D Noise
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// by Stefan Gustavson
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vec2 fade(vec2 t) {return t*t*t*(t*(t*6.0-15.0)+10.0);}
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float ClassicPerlinNoise(vec2 P){
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vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
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vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
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Pi = mod(Pi, 289.0); // To avoid truncation effects in permutation
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vec4 ix = Pi.xzxz;
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vec4 iy = Pi.yyww;
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vec4 fx = Pf.xzxz;
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vec4 fy = Pf.yyww;
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vec4 i = permute(permute(ix) + iy);
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vec4 gx = 2.0 * fract(i * 0.0243902439) - 1.0; // 1/41 = 0.024...
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vec4 gy = abs(gx) - 0.5;
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vec4 tx = floor(gx + 0.5);
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gx = gx - tx;
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vec2 g00 = vec2(gx.x,gy.x);
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vec2 g10 = vec2(gx.y,gy.y);
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vec2 g01 = vec2(gx.z,gy.z);
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vec2 g11 = vec2(gx.w,gy.w);
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vec4 norm = 1.79284291400159 - 0.85373472095314 *
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vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11));
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g00 *= norm.x;
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g01 *= norm.y;
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g10 *= norm.z;
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g11 *= norm.w;
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float n00 = dot(g00, vec2(fx.x, fy.x));
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float n10 = dot(g10, vec2(fx.y, fy.y));
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float n01 = dot(g01, vec2(fx.z, fy.z));
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float n11 = dot(g11, vec2(fx.w, fy.w));
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vec2 fade_xy = fade(Pf.xy);
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vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
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float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
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return 2.3 * n_xy;
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}
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// Simplex 2D noise
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float SimplexNoise(vec2 v){
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const vec4 C = vec4(0.211324865405187, 0.366025403784439,
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-0.577350269189626, 0.024390243902439);
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vec2 i = floor(v + dot(v, C.yy) );
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vec2 x0 = v - i + dot(i, C.xx);
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vec2 i1;
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i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0);
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vec4 x12 = x0.xyxy + C.xxzz;
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x12.xy -= i1;
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i = mod(i, 289.0);
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vec3 p = permute( permute( i.y + vec3(0.0, i1.y, 1.0 ))
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+ i.x + vec3(0.0, i1.x, 1.0 ));
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vec3 m = max(0.5 - vec3(dot(x0,x0), dot(x12.xy,x12.xy),
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dot(x12.zw,x12.zw)), 0.0);
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m = m*m ;
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m = m*m ;
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vec3 x = 2.0 * fract(p * C.www) - 1.0;
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vec3 h = abs(x) - 0.5;
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vec3 ox = floor(x + 0.5);
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vec3 a0 = x - ox;
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m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h );
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vec3 g;
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g.x = a0.x * x0.x + h.x * x0.y;
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g.yz = a0.yz * x12.xz + h.yz * x12.yw;
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return 130.0 * dot(m, g);
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} |