Shader Noise
Procedural noise creates natural-looking randomness. Unlike random(), noise is coherent—nearby inputs produce nearby outputs.
Quick Start // Simple usage float n = snoise(uv * 5.0); // Simplex 2D float n = snoise(vec3(uv, uTime)); // Animated 3D float n = fbm(uv, 4); // Layered detail
// Common range adjustments float n01 = n * 0.5 + 0.5; // [-1,1] → [0,1] float sharp = step(0.0, n); // Binary threshold float smooth = smoothstep(-0.2, 0.2, n); // Soft threshold
Noise Types Comparison Type Speed Quality Use Case Value Fastest Blocky Quick prototypes Perlin Fast Good General purpose Simplex Fast Best Modern default Worley Slower Cellular Cells, cracks, scales Value Noise
Interpolated random values at grid points. Simple but blocky.
float random(vec2 st) { return fract(sin(dot(st.xy, vec2(12.9898, 78.233))) * 43758.5453123); }
float valueNoise(vec2 st) { vec2 i = floor(st); vec2 f = fract(st);
// Smoothstep interpolation vec2 u = f * f * (3.0 - 2.0 * f);
// Four corners float a = random(i); float b = random(i + vec2(1.0, 0.0)); float c = random(i + vec2(0.0, 1.0)); float d = random(i + vec2(1.0, 1.0));
// Bilinear interpolation return mix(mix(a, b, u.x), mix(c, d, u.x), u.y); }
Simplex Noise (Recommended)
Best quality-to-performance ratio. Use this as default.
2D Simplex vec3 permute(vec3 x) { return mod(((x34.0)+1.0)x, 289.0); }
float snoise(vec2 v) { const vec4 C = vec4(0.211324865405187, 0.366025403784439, -0.577350269189626, 0.024390243902439); vec2 i = floor(v + dot(v, C.yy)); vec2 x0 = v - i + dot(i, C.xx); vec2 i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0); vec4 x12 = x0.xyxy + C.xxzz; x12.xy -= i1; i = mod(i, 289.0); vec3 p = permute(permute(i.y + vec3(0.0, i1.y, 1.0)) + i.x + vec3(0.0, i1.x, 1.0)); vec3 m = max(0.5 - vec3(dot(x0,x0), dot(x12.xy,x12.xy), dot(x12.zw,x12.zw)), 0.0); m = mm; m = mm; vec3 x = 2.0 * fract(p * C.www) - 1.0; vec3 h = abs(x) - 0.5; vec3 ox = floor(x + 0.5); vec3 a0 = x - ox; m = 1.79284291400159 - 0.85373472095314 * (a0a0 + h*h); vec3 g; g.x = a0.x * x0.x + h.x * x0.y; g.yz = a0.yz * x12.xz + h.yz * x12.yw; return 130.0 * dot(m, g); }
3D Simplex vec4 permute(vec4 x) { return mod(((x34.0)+1.0)x, 289.0); } vec4 taylorInvSqrt(vec4 r) { return 1.79284291400159 - 0.85373472095314 * r; }
float snoise(vec3 v) { const vec2 C = vec2(1.0/6.0, 1.0/3.0); const vec4 D = vec4(0.0, 0.5, 1.0, 2.0);
vec3 i = floor(v + dot(v, C.yyy)); vec3 x0 = v - i + dot(i, C.xxx);
vec3 g = step(x0.yzx, x0.xyz); vec3 l = 1.0 - g; vec3 i1 = min(g.xyz, l.zxy); vec3 i2 = max(g.xyz, l.zxy);
vec3 x1 = x0 - i1 + C.xxx; vec3 x2 = x0 - i2 + C.yyy; vec3 x3 = x0 - D.yyy;
i = mod(i, 289.0); vec4 p = permute(permute(permute( i.z + vec4(0.0, i1.z, i2.z, 1.0)) + i.y + vec4(0.0, i1.y, i2.y, 1.0)) + i.x + vec4(0.0, i1.x, i2.x, 1.0));
float n_ = 0.142857142857; vec3 ns = n_ * D.wyz - D.xzx;
vec4 j = p - 49.0 * floor(p * ns.z * ns.z);
vec4 x_ = floor(j * ns.z); vec4 y_ = floor(j - 7.0 * x_);
vec4 x = x_ ns.x + ns.yyyy; vec4 y = y_ ns.x + ns.yyyy; vec4 h = 1.0 - abs(x) - abs(y);
vec4 b0 = vec4(x.xy, y.xy); vec4 b1 = vec4(x.zw, y.zw);
vec4 s0 = floor(b0)2.0 + 1.0; vec4 s1 = floor(b1)2.0 + 1.0; vec4 sh = -step(h, vec4(0.0));
vec4 a0 = b0.xzyw + s0.xzywsh.xxyy; vec4 a1 = b1.xzyw + s1.xzywsh.zzww;
vec3 p0 = vec3(a0.xy, h.x); vec3 p1 = vec3(a0.zw, h.y); vec3 p2 = vec3(a1.xy, h.z); vec3 p3 = vec3(a1.zw, h.w);
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;
vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0); m = m * m; return 42.0 * dot(m*m, vec4(dot(p0,x0), dot(p1,x1), dot(p2,x2), dot(p3,x3))); }
Worley (Cellular) Noise
Creates cell-like patterns. Great for scales, cracks, caustics.
vec2 random2(vec2 st) { st = vec2(dot(st, vec2(127.1, 311.7)), dot(st, vec2(269.5, 183.3))); return fract(sin(st) * 43758.5453123); }
float worley(vec2 st) { vec2 i_st = floor(st); vec2 f_st = fract(st);
float minDist = 1.0;
// Check 3x3 neighborhood for (int y = -1; y <= 1; y++) { for (int x = -1; x <= 1; x++) { vec2 neighbor = vec2(float(x), float(y)); vec2 point = random2(i_st + neighbor);
// Animate points
// point = 0.5 + 0.5 * sin(uTime + 6.2831 * point);
vec2 diff = neighbor + point - f_st;
float dist = length(diff);
minDist = min(minDist, dist);
}
}
return minDist; }
// F2 - F1 variant (cracks/veins) vec2 worley2(vec2 st) { vec2 i_st = floor(st); vec2 f_st = fract(st);
float f1 = 1.0; // Closest float f2 = 1.0; // Second closest
for (int y = -1; y <= 1; y++) { for (int x = -1; x <= 1; x++) { vec2 neighbor = vec2(float(x), float(y)); vec2 point = random2(i_st + neighbor); vec2 diff = neighbor + point - f_st; float dist = length(diff);
if (dist < f1) {
f2 = f1;
f1 = dist;
} else if (dist < f2) {
f2 = dist;
}
}
}
return vec2(f1, f2); }
FBM (Fractal Brownian Motion)
Layer multiple noise octaves for natural detail at all scales.
float fbm(vec2 st, int octaves) { float value = 0.0; float amplitude = 0.5; float frequency = 1.0;
for (int i = 0; i < octaves; i++) { value += amplitude * snoise(st * frequency); frequency = 2.0; // Lacunarity amplitude = 0.5; // Gain/Persistence }
return value; }
// Configurable FBM float fbm(vec2 st, int octaves, float lacunarity, float gain) { float value = 0.0; float amplitude = 0.5; float frequency = 1.0;
for (int i = 0; i < octaves; i++) { value += amplitude * snoise(st * frequency); frequency = lacunarity; amplitude = gain; }
return value; }
FBM Variants // Ridged FBM (mountains, lightning) float ridgedFbm(vec2 st, int octaves) { float value = 0.0; float amplitude = 0.5; float frequency = 1.0;
for (int i = 0; i < octaves; i++) { float n = snoise(st * frequency); n = 1.0 - abs(n); // Ridge n = n * n; // Sharpen value += amplitude * n; frequency = 2.0; amplitude = 0.5; }
return value; }
// Turbulence (absolute value, always positive) float turbulence(vec2 st, int octaves) { float value = 0.0; float amplitude = 0.5; float frequency = 1.0;
for (int i = 0; i < octaves; i++) { value += amplitude * abs(snoise(st * frequency)); frequency = 2.0; amplitude = 0.5; }
return value; }
Domain Warping
Distort the input coordinates with noise for organic shapes.
// Simple domain warp float warpedNoise(vec2 st) { vec2 q = vec2( snoise(st), snoise(st + vec2(5.2, 1.3)) );
return snoise(st + q * 2.0); }
// Double domain warp (more complex) float doubleWarp(vec2 st) { vec2 q = vec2( fbm(st, 4), fbm(st + vec2(5.2, 1.3), 4) );
vec2 r = vec2( fbm(st + q * 4.0 + vec2(1.7, 9.2), 4), fbm(st + q * 4.0 + vec2(8.3, 2.8), 4) );
return fbm(st + r * 4.0, 4); }
// Animated warp float animatedWarp(vec2 st, float time) { vec2 q = vec2( fbm(st + vec2(0.0, 0.0), 4), fbm(st + vec2(5.2, 1.3), 4) );
vec2 r = vec2( fbm(st + q * 4.0 + vec2(1.7, 9.2) + 0.15 * time, 4), fbm(st + q * 4.0 + vec2(8.3, 2.8) + 0.126 * time, 4) );
return fbm(st + r * 4.0, 4); }
Common Use Cases Terrain Height float terrainHeight(vec2 pos) { float height = 0.0;
// Base terrain height += fbm(pos * 0.01, 6) * 100.0;
// Mountains (ridged) height += ridgedFbm(pos * 0.005, 4) * 200.0;
// Detail height += snoise(pos * 0.1) * 5.0;
return height; }
Clouds float clouds(vec2 uv, float time) { vec2 motion = vec2(time * 0.1, 0.0);
float density = fbm(uv * 3.0 + motion, 5); density = smoothstep(0.0, 0.5, density);
return density; }
Fire/Flames float fire(vec2 uv, float time) { // Upward motion uv.y -= time * 2.0;
// Turbulent distortion float turb = turbulence(uv * 4.0, 4);
// Fade out at top float fade = 1.0 - uv.y;
return turb * fade; }
Water Caustics float caustics(vec2 uv, float time) { vec2 w = worley2(uv * 8.0 + time * 0.5); return pow(1.0 - w.x, 3.0); }
Marble/Stone float marble(vec2 uv) { float n = fbm(uv * 2.0, 4); float veins = sin(uv.x * 10.0 + n * 10.0); return veins * 0.5 + 0.5; }
Performance Tips Technique Impact Fewer octaves in FBM Major speedup 2D vs 3D noise 2D ~2x faster Bake to texture Massive speedup for static Lower frequency = fewer samples Faster File Structure shader-noise/ ├── SKILL.md ├── references/ │ ├── noise-comparison.md # Visual comparison of types │ └── optimization.md # Performance techniques └── scripts/ ├── noise/ │ ├── simplex2d.glsl # Copy-paste simplex 2D │ ├── simplex3d.glsl # Copy-paste simplex 3D │ ├── worley.glsl # Copy-paste Worley │ └── fbm.glsl # FBM variants └── examples/ ├── terrain.glsl # Terrain generation ├── clouds.glsl # Cloud shader └── fire.glsl # Fire effect
Reference references/noise-comparison.md — Visual comparison of noise types references/optimization.md — Performance optimization techniques