Hash Grid Noise

Generate a random value per grid cell using a small hash function.

Overview

• Generate procedural noise and map it to color.

Learning Objectives

• Build a simple hash function
• Use floor() to create grid cells

Prerequisites

• uv-coordinates

Key Concepts

• Noise is built from random values on a grid plus smooth interpolation.

vec2 i = floor(p);
vec2 f = fract(p);
vec2 u = f*f*(3.0-2.0*f);
float n = mix(mix(a,b,u.x), mix(c,d,u.x), u.y);

• Map noise to color with mix or thresholds.

vec3 color = mix(colorA, colorB, n);

How To Implement (Step-by-step)

• Scale UV to control frequency (e.g. p = vUv * 6.0).
• Compute base noise (hash/valueNoise).
• Optionally sum octaves (FBM) for detail.
• Map noise to grayscale or color.

Self-check

• Does it compile without errors?
• Does the output match the goal?
• Are key values kept in [0,1]?

Common Mistakes

• Change frequency by scaling before fract().