/*{
  "DESCRIPTION": "Wet neon — a few neon signs smeared into dark rippling water, wavering and broken by the surface waves.",
  "CREDIT": "claude-opus-4-8",
  "INPUTS": [
    { "NAME": "ripple", "TYPE": "float", "DEFAULT": 0.5, "MIN": 0.0, "MAX": 1.5 },
    { "NAME": "waves",  "TYPE": "float", "DEFAULT": 34.0, "MIN": 12.0, "MAX": 70.0 },
    { "NAME": "glow",   "TYPE": "float", "DEFAULT": 0.8, "MIN": 0.2, "MAX": 1.6 },
    { "NAME": "speed",  "TYPE": "float", "DEFAULT": 1.0, "MIN": 0.0, "MAX": 3.0 }
  ]
}*/

float hash(vec2 p){ p = fract(p * vec2(123.34, 456.21)); p += dot(p, p + 45.32); return fract(p.x * p.y); }
float noise(vec2 p){
  vec2 i = floor(p), f = fract(p); f = f * f * (3.0 - 2.0 * f);
  float a = hash(i), b = hash(i + vec2(1.0, 0.0)), c = hash(i + vec2(0.0, 1.0)), d = hash(i + vec2(1.0, 1.0));
  return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);
}

// a soft neon column of colour `col` centred at x = cx
vec3 bar(float x, float cx, float w, vec3 col){
  float d = (x - cx) / w;
  return col * exp(-d * d);
}

vec3 lights(float x){
  vec3 c = vec3(0.0);
  c += bar(x, 0.20, 0.045, vec3(1.0, 0.10, 0.65));   // magenta
  c += bar(x, 0.40, 0.030, vec3(0.10, 0.95, 1.0));   // cyan
  c += bar(x, 0.58, 0.055, vec3(0.45, 1.0, 0.20));   // green
  c += bar(x, 0.80, 0.035, vec3(1.0, 0.55, 0.05));   // amber
  return c;
}

void main(){
  vec2 uv = gl_FragCoord.xy / RENDERSIZE;
  float t = TIME * speed;
  float depth = 1.0 - uv.y;                 // 0 at top, 1 at bottom (deeper into reflection)

  // multi-octave horizontal wander (the reflection sways with the swell), stronger deeper down
  float wob = 0.055 * sin(uv.y * 9.0 - t * 1.3)
            + 0.030 * sin(uv.y * 21.0 + t * 0.8)
            + 0.025 * (noise(vec2(uv.y * 7.0, t * 0.7)) - 0.5);
  wob *= ripple * (0.25 + 1.1 * depth);
  float x = uv.x + wob;

  // horizontal smear — neon bleeds sideways on the wet surface
  vec3 col = lights(x) * 0.5 + lights(x - 0.018) * 0.25 + lights(x + 0.018) * 0.25;

  // ripple bands break the columns into wavy horizontal streaks
  float band = sin(uv.y * waves + 4.5 * sin(uv.x * 2.5 + t * 0.6) - t * 2.0);
  band += 0.5 * sin(uv.y * waves * 2.3 - t * 3.0);   // finer secondary ripple
  band = 0.5 + 0.5 * clamp(band, -1.0, 1.0);
  col *= 0.18 + 1.2 * pow(band, 2.2);
  col *= 0.45 + 0.55 * depth;

  // specular glints where the surface crests catch the light
  float crest = pow(band, 8.0);
  col += col * crest * 0.8;

  col *= glow;
  col += (lights(x) * 0.5 + lights(x - 0.018) * 0.25 + lights(x + 0.018) * 0.25) * 0.07;  // faint core
  col = col / (1.0 + 0.5 * col);
  col = pow(max(col, 0.0), vec3(0.85));
  gl_FragColor = vec4(col, 1.0);
}