Skip to content

Instantly share code, notes, and snippets.

Show Gist options
  • Save damienmortini/ebce30cddfa78f2ecc43 to your computer and use it in GitHub Desktop.
Save damienmortini/ebce30cddfa78f2ecc43 to your computer and use it in GitHub Desktop.
// http://www.iquilezles.org/www/articles/morenoise/morenoise.htm
// Hector Arellano
float rand(vec2 co){
return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
}
const float inv289 = 0.00346020761;
vec4 mod289(vec4 x) {
return x - floor(x * (inv289)) * 289.0;
}
float mod289(float x) {
return x - floor(x * (inv289)) * 289.0;
}
vec4 permute(vec4 x) {
return mod289(((x * 34.0) + 1.0) * x);
}
float permute(float x) {
return mod289(((x * 34.0) + 1.0) * x);
}
vec4 taylorInvSqrt(vec4 r) {
return 1.79284291400159 - 0.85373472095314 * r;
}
float taylorInvSqrt(float r) {
return 1.79284291400159 - 0.85373472095314 * r;
}
vec4 grad4(float j, vec4 ip) {
const vec4 ones = vec4(1.0, 1.0, 1.0, -1.0);
vec4 p;
vec4 s;
p.xyz = floor( fract (vec3(j) * ip.xyz) * 7.0) * ip.z - 1.0;
p.w = 1.5 - dot(abs(p.xyz), ones.xyz);
s = vec4(lessThan(p, vec4(0.0)));
p.xyz = p.xyz + (s.xyz * 2.0 - 1.0) * s.www;
return p;
}
#define F4 0.309016994374947451
vec4 simplexNoiseDerivatives (vec4 v) {
const vec4 C = vec4(0.138196601125011, 0.276393202250021, 0.414589803375032, -0.447213595499958);
vec4 i = floor(v + dot(v, vec4(F4)));
vec4 x0 = v - i + dot(i, C.xxxx);
vec4 i0;
vec3 isX = step(x0.yzw, x0.xxx);
vec3 isYZ = step(x0.zww, x0.yyz);
i0.x = isX.x + isX.y + isX.z;
i0.yzw = 1.0 - isX;
i0.y += isYZ.x + isYZ.y;
i0.zw += 1.0 - isYZ.xy;
i0.z += isYZ.z;
i0.w += 1.0 - isYZ.z;
vec4 i3 = clamp(i0, 0.0, 1.0);
vec4 i2 = clamp(i0 - 1.0, 0.0, 1.0);
vec4 i1 = clamp(i0 - 2.0, 0.0, 1.0);
vec4 x1 = x0 - i1 + C.xxxx;
vec4 x2 = x0 - i2 + C.yyyy;
vec4 x3 = x0 - i3 + C.zzzz;
vec4 x4 = x0 + C.wwww;
i = mod289(i);
float j0 = permute( permute( permute( permute(i.w) + i.z) + i.y) + i.x);
vec4 j1 = permute( permute( permute( permute (
i.w + vec4(i1.w, i2.w, i3.w, 1.0))
+ i.z + vec4(i1.z, i2.z, i3.z, 1.0))
+ i.y + vec4(i1.y, i2.y, i3.y, 1.0))
+ i.x + vec4(i1.x, i2.x, i3.x, 1.0));
// 1/294 1/49 1/7
vec4 ip = vec4(0.00340136054, 0.02040816326, 0.14285714285, 0.0) ;
vec4 p0 = grad4(j0, ip);
vec4 p1 = grad4(j1.x, ip);
vec4 p2 = grad4(j1.y, ip);
vec4 p3 = grad4(j1.z, ip);
vec4 p4 = grad4(j1.w, ip);
vec4 norm = taylorInvSqrt(vec4(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3)));
p0 *= norm.x;
p1 *= norm.y;
p2 *= norm.z;
p3 *= norm.w;
p4 *= taylorInvSqrt(dot(p4, p4));
//value of contributions from each corner at point
vec3 values0 = vec3(dot(p0, x0), dot(p1, x1), dot(p2, x2));
vec2 values1 = vec2(dot(p3, x3), dot(p4, x4));
//(0.5 - x^2) where x is the distance
vec3 m0 = max(0.5 - vec3(dot(x0, x0), dot(x1, x1), dot(x2, x2)), 0.0);
vec2 m1 = max(0.5 - vec2(dot(x3, x3), dot(x4, x4)), 0.0);
vec3 temp0 = -6.0 * m0 * m0 * values0 + m0 * values0;
vec2 temp1 = -6.0 * m1 * m1 * values1 + m1 * values1;
vec3 mmm0 = m0 * m0 * m0;
vec2 mmm1 = m1 * m1 * m1;
float dx = temp0[0] * x0.x + temp0[1] * x1.x + temp0[2] * x2.x + temp1[0] * x3.x + temp1[1] * x4.x + mmm0[0] * p0.x + mmm0[1] * p1.x + mmm0[2] * p2.x + mmm1[0] * p3.x + mmm1[1] * p4.x;
float dy = temp0[0] * x0.y + temp0[1] * x1.y + temp0[2] * x2.y + temp1[0] * x3.y + temp1[1] * x4.y + mmm0[0] * p0.y + mmm0[1] * p1.y + mmm0[2] * p2.y + mmm1[0] * p3.y + mmm1[1] * p4.y;
float dz = temp0[0] * x0.z + temp0[1] * x1.z + temp0[2] * x2.z + temp1[0] * x3.z + temp1[1] * x4.z + mmm0[0] * p0.z + mmm0[1] * p1.z + mmm0[2] * p2.z + mmm1[0] * p3.z + mmm1[1] * p4.z;
float dw = temp0[0] * x0.w + temp0[1] * x1.w + temp0[2] * x2.w + temp1[0] * x3.w + temp1[1] * x4.w + mmm0[0] * p0.w + mmm0[1] * p1.w + mmm0[2] * p2.w + mmm1[0] * p3.w + mmm1[1] * p4.w;
return vec4(dx, dy, dz, dw) * 49.0;
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment