import { tslFn } from '../shadernode/ShaderNode.js'; export const getDistanceAttenuation = tslFn( ( inputs ) => { const { lightDistance, cutoffDistance, decayExponent } = inputs; // based upon Frostbite 3 Moving to Physically-based Rendering // page 32, equation 26: E[window1] // https://seblagarde.files.wordpress.com/2015/07/course_notes_moving_frostbite_to_pbr_v32.pdf const distanceFalloff = lightDistance.pow( decayExponent ).max( 0.01 ).reciprocal(); return cutoffDistance.greaterThan( 0 ).cond( distanceFalloff.mul( lightDistance.div( cutoffDistance ).pow4().oneMinus().clamp().pow2() ), distanceFalloff ); } ); // validated