resetPlaneStacks() {
        // clear the plane stacks
        this.stacks.pingPong = [];
        this.stacks.renderTargets = [];
        this.stacks.opaque = [];
        this.stacks.transparent = [];

        // rebuild them with the new plane indexes
        for(let i = 0; i < this.renderer.planes.length; i++) {
            this.addPlane(this.renderer.planes[i]);
        }
    }
Reset the plane stacks (used when disposing a plane)
*