60 lines
2.0 KiB
JavaScript
60 lines
2.0 KiB
JavaScript
import F_Schlick from './F_Schlick.js';
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import V_GGX_SmithCorrelated from './V_GGX_SmithCorrelated.js';
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import V_GGX_SmithCorrelated_Anisotropic from './V_GGX_SmithCorrelated_Anisotropic.js';
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import D_GGX from './D_GGX.js';
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import D_GGX_Anisotropic from './D_GGX_Anisotropic.js';
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import { transformedNormalView } from '../../accessors/NormalNode.js';
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import { positionViewDirection } from '../../accessors/PositionNode.js';
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import { iridescence, alphaT, anisotropyT, anisotropyB } from '../../core/PropertyNode.js';
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import { tslFn, defined } from '../../shadernode/ShaderNode.js';
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// GGX Distribution, Schlick Fresnel, GGX_SmithCorrelated Visibility
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const BRDF_GGX = tslFn( ( inputs ) => {
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const { lightDirection, f0, f90, roughness, f, USE_IRIDESCENCE, USE_ANISOTROPY } = inputs;
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const normalView = inputs.normalView || transformedNormalView;
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const alpha = roughness.pow2(); // UE4's roughness
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const halfDir = lightDirection.add( positionViewDirection ).normalize();
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const dotNL = normalView.dot( lightDirection ).clamp();
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const dotNV = normalView.dot( positionViewDirection ).clamp(); // @ TODO: Move to core dotNV
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const dotNH = normalView.dot( halfDir ).clamp();
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const dotVH = positionViewDirection.dot( halfDir ).clamp();
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let F = F_Schlick( { f0, f90, dotVH } );
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let V, D;
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if ( defined( USE_IRIDESCENCE ) ) {
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F = iridescence.mix( F, f );
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}
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if ( defined( USE_ANISOTROPY ) ) {
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const dotTL = anisotropyT.dot( lightDirection );
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const dotTV = anisotropyT.dot( positionViewDirection );
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const dotTH = anisotropyT.dot( halfDir );
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const dotBL = anisotropyB.dot( lightDirection );
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const dotBV = anisotropyB.dot( positionViewDirection );
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const dotBH = anisotropyB.dot( halfDir );
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V = V_GGX_SmithCorrelated_Anisotropic( { alphaT, alphaB: alpha, dotTV, dotBV, dotTL, dotBL, dotNV, dotNL } );
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D = D_GGX_Anisotropic( { alphaT, alphaB: alpha, dotNH, dotTH, dotBH } );
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} else {
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V = V_GGX_SmithCorrelated( { alpha, dotNL, dotNV } );
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D = D_GGX( { alpha, dotNH } );
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}
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return F.mul( V ).mul( D );
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} ); // validated
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export default BRDF_GGX;
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