To detect a win condition, we're going to periodically check whether a racer is overlapping with the finish line item. When one of them is, we'll declare it the winner and offer the option to play again.
Collision detection between items is slightly awkward with the Tkinter Canvas widget. We have to pass a set of bounding box coordinates to find_overlapping(), which returns a tuple of item identifiers that overlap with the bounding box.
Let's create an overlapping() method for our Racer class:
def overlapping(self):
bbox = self.canvas.bbox(self.id)
overlappers = self.canvas.find_overlapping(*bbox)
return [x for x in overlappers if x!=self.id]
This method retrieves the bounding box of the Racer item ...
