tonemapping.ts

import { Fn, float } from 'three/tsl'

/**
 * Applies Reinhard tonemapping to a color vector.
 * @param {vec3} _color Input color vector
 * @returns {vec3} Tonemapped color
 */
export const reinhardTonemap = Fn(([_color]) => {
  return _color.div(_color.add(1.0))
})

/**
 * Applies Uncharted2 filmic tonemapping to a color vector.
 * @param {vec3} color Input color vector
 * @returns {vec3} Tonemapped color
 */
export const uncharted2Tonemap = Fn(([color]) => {
  const _color = color
  _color.mulAssign(16.0)

  const a = float(0.15)
  const b = float(0.5)
  const c = float(0.1)
  const d = float(0.2)
  const e = float(0.02)
  const f = float(0.3)

  return _color
    .mul(a.mul(_color).add(c.mul(b)))
    .add(d.mul(e))
    .div(_color.mul(a.mul(_color).add(b)).add(d.mul(f)))
    .sub(e.div(f))
})

/**
 * Applies ACES tonemapping to a color vector.
 * @param {vec3} _color Input color vector
 * @returns {vec3} Tonemapped color
 */
export const acesTonemap = Fn(([_color]) => {
  const a = float(2.51)
  const b = float(0.03)
  const c = float(2.43)
  const d = float(0.59)
  const e = float(0.14)

  return _color.mul(a.mul(_color).add(b)).div(_color.mul(c.mul(_color).add(d)).add(e))
})