updateProjectionMatrix() {

		const near = this.near;
		let top = near * Math.tan( DEG2RAD * 0.5 * this.fov ) / this.zoom;
		let height = 2 * top;
		let width = this.aspect * height;
		let left = -0.5 * width;
		const view = this.view;

		if ( this.view !== null && this.view.enabled ) {

			const fullWidth = view.fullWidth,
				fullHeight = view.fullHeight;

			left += view.offsetX * width / fullWidth;
			top -= view.offsetY * height / fullHeight;
			width *= view.width / fullWidth;
			height *= view.height / fullHeight;

		}

		const skew = this.filmOffset;
		if ( skew !== 0 ) left += near * skew / this.getFilmWidth();

		this.projectionMatrix.makePerspective( left, left + width, top, top - height, near, this.far, this.coordinateSystem );

		this.projectionMatrixInverse.copy( this.projectionMatrix ).invert();

	}
Updates the camera's projection matrix. Must be called after any change of
camera properties.