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