setup( builder ) {

		if ( this._sampleRenderTarget === null ) {

			this._sampleRenderTarget = this.renderTarget.clone();

		}

		let sampleTexture;

		const passMRT = this.getMRT();

		if ( passMRT !== null ) {

			const outputs = {};

			for ( const name in passMRT.outputNodes ) {

				const index = getTextureIndex( this._sampleRenderTarget.textures, name );

				if ( index >= 0 ) {

					outputs[ name ] = texture( this._sampleRenderTarget.textures[ index ] ).mul( this.sampleWeight );

				}

			}

			sampleTexture = mrt( outputs );

		} else {

			sampleTexture = texture( this._sampleRenderTarget.texture ).mul( this.sampleWeight );

		}

		this._quadMesh.material = new NodeMaterial();
		this._quadMesh.material.fragmentNode = unpremultiplyAlpha( sampleTexture );
		this._quadMesh.material.transparent = true;
		this._quadMesh.material.depthTest = false;
		this._quadMesh.material.depthWrite = false;
		this._quadMesh.material.premultipliedAlpha = true;
		this._quadMesh.material.blending = AdditiveBlending;
		this._quadMesh.material.name = 'SSAA';

		return super.setup( builder );

	}
This method is used to setup the effect's MRT configuration and quad mesh.

@param {NodeBuilder} builder - The current node builder.
@return {PassTextureNode}