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- import { tslFn, vec2, vec4 } from '../../shadernode/ShaderNode.js';
- // Analytical approximation of the DFG LUT, one half of the
- // split-sum approximation used in indirect specular lighting.
- // via 'environmentBRDF' from "Physically Based Shading on Mobile"
- // https://www.unrealengine.com/blog/physically-based-shading-on-mobile
- const DFGApprox = tslFn( ( { roughness, dotNV } ) => {
- const c0 = vec4( - 1, - 0.0275, - 0.572, 0.022 );
- const c1 = vec4( 1, 0.0425, 1.04, - 0.04 );
- const r = roughness.mul( c0 ).add( c1 );
- const a004 = r.x.mul( r.x ).min( dotNV.mul( - 9.28 ).exp2() ).mul( r.x ).add( r.y );
- const fab = vec2( - 1.04, 1.04 ).mul( a004 ).add( r.zw );
- return fab;
- } ).setLayout( {
- name: 'DFGApprox',
- type: 'vec2',
- inputs: [
- { name: 'roughness', type: 'float' },
- { name: 'dotNV', type: 'vec3' }
- ]
- } );
- export default DFGApprox;
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