Character getting stuck when colliding from the top

Question

when my character goes onto a box that I am trying to make him collide with he gets stuck. The way I have it configured is that at the end of every frame, the characters x and y values are stored in old x and old y, and if he is colliding with the box his x and y are reverted to old x and old y. This seems to work when walking into the box, but when the character jumps on the box he gets stuck and can't move. I think this has something to do with his x and y being infinitely pushed to oldX and oldY, but I don't know how to fix this. Thanks for the help!

 for(int x = 0; x < collidables.length; x++){
        if(collidables[x] instanceof QuestionBox){
            collidables[x].bottomCollision(mario);
        }


        if(mario.intersects(collidables[x].boxRectangle)){
            mario.setMarioX(mario.oldX);
            mario.setMarioY(mario.oldY);

        }
    }

        mario.oldX = mario.getMarioX();
        mario.oldY = mario.getMarioY();

Here is the code for what happens upon a collision. Thanks for the help!

Answer 1

Short Answer: you're going to have to treat "falling" and "moving" each as a separate action, each with the ability to be undone separately, instead of combining them into a single undo action.

Long Answer: Lets just simulate it out: o is current position, x is our saved position, _ is a wall, . is empty space.

  ...o.......
  ___________

okay, we're holding down the "move right" button, so lets move Mario right.

  ...x..o....
  ___________

okay, now gravity moves Mario down

  ...x.......
  ______o____

uh wait, Mario's intersecting the wall! lets move back to our old location

  ...o.......
  ___________

Wait... where did my "move right" go?