setComponents( x, y, z, w ) {

		this.normal.set( x, y, z );
		this.constant = w;

		return this;

	}
Sets the plane components by defining `x`, `y`, `z` as the
plane normal and `w` as the constant.

@param {number} x - The value for the normal's x component.
@param {number} y - The value for the normal's y component.
@param {number} z - The value for the normal's z component.
@param {number} w - The constant value.
@return {Plane} A reference to this plane.