@openhps/core
Version:
Open Hybrid Positioning System - Core component
26 lines (23 loc) • 672 B
JavaScript
import { Fn } from '../../tsl/TSLBase.js';
// Microfacet Models for Refraction through Rough Surfaces - equation (33)
// http://graphicrants.blogspot.com/2013/08/specular-brdf-reference.html
// alpha is "roughness squared" in Disney’s reparameterization
const D_GGX = /*@__PURE__*/Fn(({
alpha,
dotNH
}) => {
const a2 = alpha.pow2();
const denom = dotNH.pow2().mul(a2.oneMinus()).oneMinus(); // avoid alpha = 0 with dotNH = 1
return a2.div(denom.pow2()).mul(1 / Math.PI);
}).setLayout({
name: 'D_GGX',
type: 'float',
inputs: [{
name: 'alpha',
type: 'float'
}, {
name: 'dotNH',
type: 'float'
}]
}); // validated
export default D_GGX;