reset( renderTarget ) {

		if ( renderTarget === undefined ) {

			const size = this.renderer.getSize( new Vector2() );
			this._pixelRatio = this.renderer.getPixelRatio();
			this._width = size.width;
			this._height = size.height;

			renderTarget = this.renderTarget1.clone();
			renderTarget.setSize( this._width * this._pixelRatio, this._height * this._pixelRatio );

		}

		this.renderTarget1.dispose();
		this.renderTarget2.dispose();
		this.renderTarget1 = renderTarget;
		this.renderTarget2 = renderTarget.clone();

		this.writeBuffer = this.renderTarget1;
		this.readBuffer = this.renderTarget2;

	}
Resets the internal state of the EffectComposer.

@param {WebGLRenderTarget} [renderTarget] - This render target has the same purpose like
the one from the constructor. If set, it is used to setup the read and write buffers.