Stopping a Sprite Walking Past Platform Edges

[Jonathan Cauldwell]

For some ladders and levels games where the player cannot jump, you might want to stop the player moving past the edge of a platform. That can be done like this:

IF KEY 1
 IF CANGOLEFT
   SUBTRACT 16 FROM Y
   IF CANGODOWN
     ADD 16 TO Y
   ELSE
     ADD 14 TO Y
     ANIMATE
   ENDIF
 ENDIF
ENDIF
IF KEY 0
 IF CANGORIGHT
   ADD 16 TO Y
   IF CANGODOWN
     SUBTRACT 16 FROM Y
   ELSE
     SUBTRACT 14 FROM Y
     ANIMATE
   ENDIF
 ENDIF
ENDIF