#define IS_NEXT_FRAME(f, g) (IS_NEW_FRAME(f, g) && (f) > 0)
#define IS_LOOP_SOUND(s) (sound_info[s].loop)
+#define IS_LOOP_MUSIC(s) (music_info[s].loop)
#define IS_SPECIAL_GFX_ARG(a) ((a) >= 0 && (a) < NUM_SPECIAL_GFX_ARGS)
boolean can_pass_to_walkable; /* player can pass to empty or walkable tile */
boolean grow_into_diggable; /* amoeba can grow into anything diggable */
boolean auto_exit_sokoban; /* automatically finish solved Sokoban levels */
+ boolean solved_by_one_player; /* level is solved if one player enters exit */
boolean continuous_snapping; /* repeated snapping without releasing key */
boolean block_snap_field; /* snapping blocks field to show animation */