How to show a "Moves preview"?

I’m building a module about a car racing game i’m developing with some friend.
Car are rectangle pawns (a la “Car Wars”) and they cannot move “freely”, but have to choose from a set of “maneuvers” (30°, 45° or 90° bends, drifts, etc.).
So i’d like to show a “move preview”, and then the user “confirms” the choosen maneuver.

The way i’m seeing to do that is to draw semi/transparent “moves” pngs to be used as layers: The user should press the keys to see where the car will go (thus activating the related layer) … and then just press “Enter”.
This last part is the one i can’t figure… how to “know” , at the Enter key event, what was the choosen move, hide that layer, and move the car to that point?
How to switch off a layer and turn on another each time the user press one “move key”?
All this “layering” will result in a looooonng chain of undo commands? If yes, this will be a very bad method…

Now, i may just have got a wrong “global” vision and maybe there’s a better way to do that…
I’m hoping in suggestions.


You can use the Trigger trait on a piece to combine multiple actions in one action. Sounds like in this case, you will need to use multiple trigger traits.