/*
     *  Actor move to the step
     */
    protected void MoveTo(Step nextStep)
    {
        if( step.floorGimicOnStep != null ) {
            step.floorGimicOnStep.ActorLeaveFloorAction(this);
        }

        nextStep.actorOnStep = this;
        step.actorOnStep = null;
        step = nextStep;
        transform.position = nextStep.GetActorPos();

        if( nextStep.floorGimicOnStep != null ) {
            nextStep.floorGimicOnStep.ActorEnterFloorAction(this);
        }
    }