void updateInputDirection(); /**< if controller was pressed, update input_direction */
void tryStartWalking(); /**< try starting to walk in input_direction */
void tryContinueWalking(float elapsed_time); /**< try to continue walking in current direction */
void updateInputDirection(); /**< if controller was pressed, update input_direction */
void tryStartWalking(); /**< try starting to walk in input_direction */
void tryContinueWalking(float elapsed_time); /**< try to continue walking in current direction */