第 1 课：Random 1D

实现

uniform vec2 iResolution;

float random(float x) {
  float r = fract(sin(x * 12.34) * 1234.5678);
  return r * 2.0 - 1.0;
}

void main() {
  vec2 uv = gl_FragCoord.xy / iResolution.xy;

  float noiseValue = random(uv.x);
  noiseValue = noiseValue * 0.5 + 0.5;

  gl_FragColor = vec4(vec3(noiseValue), 1.0);
}