void set_terrain_blocked();
//short dist(location p1,location p2);
//short ex_sqrt(short val);
//short vdist(location p1,location p2) ;
bool adjacent(location p1,location p2);
bool point_onscreen(location center,location check);
short set_direction (location old_pt, location new_pt);
location global_to_local(location global);
location local_to_global(location local);
bool loc_off_world(location p1);
bool loc_off_act_area(location p1);
location get_cur_loc();
short short_can_see(shortloc p1,shortloc p2);
bool is_lava(short x,short y);
short can_see(location p1,location p2,short mode);
short get_obscurity(short x,short y);
unsigned short coord_to_ter(short x,short y);
bool is_container(location loc);
void update_explored(location dest);
bool is_blocked(location to_check);
bool monst_on_space(location loc,short m_num);
short monst_there(location where) ;
bool monst_can_be_there(location loc,short m_num);
bool monst_adjacent(location loc,short m_num);
bool monst_can_see(short m_num,location l);
bool party_can_see_monst(short m_num);
bool can_see_monst(location l,short m_num);
bool outd_is_blocked(location to_check);
bool special_which_blocks_monst(location to_check);
bool is_special(location to_check);
bool outd_is_special(location to_check);
bool impassable(unsigned short terrain_to_check);
short get_blockage(unsigned short terrain_type);
short light_radius();
bool pt_in_light(location from_where,location to_where) ;// Assumes, of course, in town or combat
bool combat_pt_in_light(location to_where);
bool party_sees_a_monst(); // Returns true is a hostile monster is in sight.
short party_can_see(location where);
location push_loc(location from_where,location to_where);
bool spot_impassable(short i,short  j);
void swap_ter(short i,short j,unsigned short ter1,unsigned short ter2);
void alter_space(short i,short j,unsigned short ter);