You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
19 lines
629 B
19 lines
629 B
2 years ago
|
import { ShaderNode, add, sub, mul, exp2 } from '../../shadernode/ShaderNodeBaseElements.js';
|
||
|
|
|
||
|
|
const F_Schlick = new ShaderNode( ( inputs ) => {
|
||
|
|
|
||
|
|
const { f0, f90, dotVH } = inputs;
|
||
|
|
|
||
|
|
// Original approximation by Christophe Schlick '94
|
||
|
|
// float fresnel = pow( 1.0 - dotVH, 5.0 );
|
||
|
|
|
||
|
|
// Optimized variant (presented by Epic at SIGGRAPH '13)
|
||
|
|
// https://cdn2.unrealengine.com/Resources/files/2013SiggraphPresentationsNotes-26915738.pdf
|
||
|
|
const fresnel = exp2( mul( sub( mul( - 5.55473, dotVH ), 6.98316 ), dotVH ) );
|
||
|
|
|
||
|
|
return add( mul( f0, sub( 1.0, fresnel ) ), mul( f90, fresnel ) );
|
||
|
|
|
||
|
|
} ); // validated
|
||
|
|
|
||
|
|
export default F_Schlick;
|