Twisty Little Maze

A simple Playdate game that demonstrates restricting the player's movement to the horizontal or vertical axis in the Pulp tile-based game engine.

The approach used here has four parts:

1. We store the "real" player location in two globals, player_x and player_y
2. We only update player_x when motion is allowed in the horizontal direction, and only update player_y when motion is allowed in the vertical direction.
3. Because the Pulp framework will automatically update the player's position, we have to immediately correct it back to player_x, player_y using goto.
4. Because an update even will be generated following the goto, we also have to suppress the update handler in that case. To do this, we set another global, goto_triggered, before executing the goto, and then, in the handler, when goto_triggered is set, we do nothing except clear goto_triggered.

None of the built-in solid object collision detection works when we do the above, so we also have to add our own checks for what the player is allowed to pass through. As you'll see in the game (and code!), this also opened the door ahem for some additional features.