Keeping Score

Just like in the gem catcher program, we'll use a variable named score to keep track of our score.

score = 0

We'll increase our score each time the obstacle disappears off the left side of the screen. Inside update(), let's change this...

  for actor in obstacles:
    actor.x -= 8

...into this...

  for actor in obstacles:
    actor.x -= 8
    if actor.x < -50:
      score += 1

This is what each line means...

if actor.x < -50 : When the x position is less than -50, the actor is most probably outside of the screen. So we will...

obstacles.remove(actor) : Remove the actor from the obstacles list...

score += 1 : ...and increase score by 1. Remember to declare score as a global!.

Drawing Obstacles and Score

The obstacles won't appear on screen if we don't draw it inside the draw() function. So let's add in...

for actor in obstacles:

This will go through the list of obstacles and draw each one.

We should also display the score on screen using...

screen.draw.text('Score: ' + str(score), (15,10), color=(0,0,0), fontsize=30)

Feel free to change the color, position, or fontsize.