copy( source ) {

		this.name = source.name;

		this.blending = source.blending;
		this.side = source.side;
		this.vertexColors = source.vertexColors;

		this.opacity = source.opacity;
		this.transparent = source.transparent;

		this.blendSrc = source.blendSrc;
		this.blendDst = source.blendDst;
		this.blendEquation = source.blendEquation;
		this.blendSrcAlpha = source.blendSrcAlpha;
		this.blendDstAlpha = source.blendDstAlpha;
		this.blendEquationAlpha = source.blendEquationAlpha;
		this.blendColor.copy( source.blendColor );
		this.blendAlpha = source.blendAlpha;

		this.depthFunc = source.depthFunc;
		this.depthTest = source.depthTest;
		this.depthWrite = source.depthWrite;

		this.stencilWriteMask = source.stencilWriteMask;
		this.stencilFunc = source.stencilFunc;
		this.stencilRef = source.stencilRef;
		this.stencilFuncMask = source.stencilFuncMask;
		this.stencilFail = source.stencilFail;
		this.stencilZFail = source.stencilZFail;
		this.stencilZPass = source.stencilZPass;
		this.stencilWrite = source.stencilWrite;

		const srcPlanes = source.clippingPlanes;
		let dstPlanes = null;

		if ( srcPlanes !== null ) {

			const n = srcPlanes.length;
			dstPlanes = new Array( n );

			for ( let i = 0; i !== n; ++ i ) {

				dstPlanes[ i ] = srcPlanes[ i ].clone();

			}

		}

		this.clippingPlanes = dstPlanes;
		this.clipIntersection = source.clipIntersection;
		this.clipShadows = source.clipShadows;

		this.shadowSide = source.shadowSide;

		this.colorWrite = source.colorWrite;

		this.precision = source.precision;

		this.polygonOffset = source.polygonOffset;
		this.polygonOffsetFactor = source.polygonOffsetFactor;
		this.polygonOffsetUnits = source.polygonOffsetUnits;

		this.dithering = source.dithering;

		this.alphaTest = source.alphaTest;
		this.alphaHash = source.alphaHash;
		this.alphaToCoverage = source.alphaToCoverage;
		this.premultipliedAlpha = source.premultipliedAlpha;
		this.forceSinglePass = source.forceSinglePass;

		this.visible = source.visible;

		this.toneMapped = source.toneMapped;

		this.userData = JSON.parse( JSON.stringify( source.userData ) );

		return this;

	}
Copies the values of the given material to this instance.

@param {Material} source - The material to copy.
@return {Material} A reference to this instance.