GdDirection gd_direction_from_keypress(boolean up, boolean down, boolean left, boolean right);
void gd_cave_iterate(GdCave *cave, GdDirection player_move, boolean player_fire, boolean suicide);
void set_initial_cave_speed(GdCave *cave);
GdDirection gd_direction_from_keypress(boolean up, boolean down, boolean left, boolean right);
void gd_cave_iterate(GdCave *cave, GdDirection player_move, boolean player_fire, boolean suicide);
void set_initial_cave_speed(GdCave *cave);