three.js/src/renderers/shaders/ShaderChunk/lights_physical_fragment.glsl.js

export default /* glsl */`
PhysicalMaterial material;
material.diffuseColor = diffuseColor.rgb * ( 1.0 - metalnessFactor );
material.specularRoughness = clamp( roughnessFactor, 0.04, 1.0 );

#ifdef REFLECTIVITY

	material.specularColor = mix( vec3( MAXIMUM_SPECULAR_COEFFICIENT * pow2( reflectivity ) ), diffuseColor.rgb, metalnessFactor );

#else

	material.specularColor = mix( vec3( DEFAULT_SPECULAR_COEFFICIENT ), diffuseColor.rgb, metalnessFactor );

#endif

#ifdef CLEARCOAT
	material.clearCoat = saturate( clearCoat ); // Burley clearcoat model
	material.clearCoatRoughness = clamp( clearCoatRoughness, 0.04, 1.0 );
#endif
`;