4_3_noiseQuality

Code 4.5, Figure 4.6:

4_3_noiseQuality.frag

#version 300 es precision highp float; precision highp int; out vec4 fragColor; uniform float u_time; uniform vec2 u_resolution; int channel; vec2[4] diag = vec2[]( // 0.70710678 = 1.0 / sqrt(2.0) vec2(0.70710678,0.70710678), vec2(-0.70710678,0.70710678), vec2(0.70710678,-0.70710678), vec2(-0.70710678,-0.70710678) ); vec2[4] axis = vec2[]( vec2(1, 0), vec2(-1, 0), vec2(0, 1), vec2(0, -1) ); uvec3 k = uvec3(0x456789abu, 0x6789ab45u, 0x89ab4567u); uvec3 u = uvec3(1, 2, 3); const uint UINT_MAX = 0xffffffffu; uvec2 uhash22(uvec2 n){ n ^= (n.yx << u.xy); n ^= (n.yx >> u.xy); n *= k.xy; n ^= (n.yx << u.xy); return n * k.xy; } float gnoise21(vec2 p){ vec2 n = floor(p); vec2 f = fract(p); float[4] v; for (int j = 0; j < 2; j ++){ for (int i = 0; i < 2; i++){ uvec2 m = floatBitsToUint(n + vec2(i, j)); uint ind = (uhash22(m).x >> 30); if (channel == 0){ v[i+2*j] = dot(diag[ind], f - vec2(i, j)); } else { v[i+2*j] = dot(axis[ind], f - vec2(i, j)); } } } f = f * f * f * (10.0 - 15.0 * f + 6.0 * f * f); return 0.5 * mix(mix(v[0], v[1], f[0]), mix(v[2], v[3], f[0]), f[1]) + 0.5; } void main(){ vec2 pos = gl_FragCoord.xy / min(u_resolution.x, u_resolution.y); channel = int(gl_FragCoord.x * 2.0 / u_resolution.x); pos = 10.0 * pos + u_time; float v = gnoise21(pos); if (v > 0.85 || v < 0.15){ fragColor.rgb = vec3(1.,0.,0.); } else { fragColor.rgb = vec3(v); } fragColor.a = 1.0; }

#version 300 es
precision highp float;
precision highp int;
out vec4 fragColor;
uniform float u_time;
uniform vec2 u_resolution;
int channel;

vec2[4] diag = vec2[](  // 0.70710678 = 1.0 / sqrt(2.0)
  vec2(0.70710678,0.70710678),
  vec2(-0.70710678,0.70710678),
  vec2(0.70710678,-0.70710678),
  vec2(-0.70710678,-0.70710678)
);

vec2[4] axis = vec2[](
  vec2(1, 0),
  vec2(-1, 0),
  vec2(0, 1),
  vec2(0, -1)
);

uvec3 k = uvec3(0x456789abu, 0x6789ab45u, 0x89ab4567u);
uvec3 u = uvec3(1, 2, 3);
const uint UINT_MAX = 0xffffffffu;

uvec2 uhash22(uvec2 n){
  n ^= (n.yx << u.xy);
  n ^= (n.yx >> u.xy);
  n *= k.xy;
  n ^= (n.yx << u.xy);
  return n * k.xy;
}

float gnoise21(vec2 p){
  vec2 n = floor(p);
  vec2 f = fract(p);
  float[4] v;
  for (int j = 0; j < 2; j ++){
    for (int i = 0; i < 2; i++){
      uvec2 m = floatBitsToUint(n + vec2(i, j));
      uint ind = (uhash22(m).x >> 30);
      if (channel == 0){
        v[i+2*j] = dot(diag[ind], f - vec2(i, j));
      } else {
        v[i+2*j] = dot(axis[ind], f - vec2(i, j));
      }
    }
  }
  f = f * f * f * (10.0 - 15.0 * f + 6.0 * f * f);
  return 0.5 * mix(mix(v[0], v[1], f[0]), mix(v[2], v[3], f[0]), f[1]) + 0.5;
}

void main(){
  vec2 pos = gl_FragCoord.xy / min(u_resolution.x, u_resolution.y);
  channel = int(gl_FragCoord.x * 2.0 / u_resolution.x);
  pos = 10.0 * pos + u_time;
  float v = gnoise21(pos);
  if (v > 0.85 || v < 0.15){
    fragColor.rgb = vec3(1.,0.,0.);
  }   else {
    fragColor.rgb = vec3(v);
  }
  fragColor.a = 1.0;
}