17 lines
549 B
JavaScript
17 lines
549 B
JavaScript
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import { tslFn } from '../../shadernode/ShaderNode.js';
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const F_Schlick = tslFn( ( { f0, f90, dotVH } ) => {
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// Original approximation by Christophe Schlick '94
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// float fresnel = pow( 1.0 - dotVH, 5.0 );
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// Optimized variant (presented by Epic at SIGGRAPH '13)
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// https://cdn2.unrealengine.com/Resources/files/2013SiggraphPresentationsNotes-26915738.pdf
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const fresnel = dotVH.mul( - 5.55473 ).sub( 6.98316 ).mul( dotVH ).exp2();
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return f0.mul( fresnel.oneMinus() ).add( f90.mul( fresnel ) );
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} ); // validated
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export default F_Schlick;
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