// Common color space and tone mapping functions.

// sRGB to Linear approximation
// Note: Assumes input is in sRGB color space.
fn sRGB(t: vec3<f32>) -> vec3<f32> {
  return mix(1.055 * pow(t, vec3<f32>(1.0/2.4)) - 0.055, 12.92 * t, step(t, vec3<f32>(0.0031308)));
}

// ACES Filmic Tone Mapping (Approximate)
// A common tone mapping algorithm used in games and film.
fn aces_approx(v_in: vec3<f32>) -> vec3<f32> {
  var v = max(v_in, vec3<f32>(0.0));
  v *= 0.6;
  let a = 2.51;
  let b = 0.03;
  let c = 2.43;
  let d = 0.59;
  let e = 0.14;
  return clamp((v * (a * v + b)) / (v * (c * v + d) + e), vec3<f32>(0.0), vec3<f32>(1.0));
}

// HSV to RGB conversion
const hsv2rgb_K = vec4<f32>(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
fn hsv2rgb(c: vec3<f32>) -> vec3<f32> {
  let p = abs(fract(c.xxx + hsv2rgb_K.xyz) * 6.0 - hsv2rgb_K.www);
  return c.z * mix(hsv2rgb_K.xxx, clamp(p - hsv2rgb_K.xxx, vec3<f32>(0.0), vec3<f32>(1.0)), c.y);
}