/** Returns zero if a unisolid tile is non-solid due to the movement
* direction, non-zero if the tile is solid due to direction. */
- bool check_movement_unisolid (const Vector movement) const;
+ bool check_movement_unisolid (const Vector& movement) const;
/** Returns zero if a unisolid tile is non-solid due to the position of the
* tile and the object, non-zero if the tile is solid. */