Monday 20:00 Python Practice 20.12.21.

Question 1:
Continue modify the program we made in the class:

1. 1. to use spritecollide to let the fighter collect energy crystals,
   2. Create a variable score, if the energy crystal is collected, the score will increase

Question 2:

In the class Laser and Explosion. We showed you how to load different image to switch costumes. 

1. 1.  Please made a class Planet, it will contains following methods:

      __init__(self) - It initials the Planet from a random centerx position, and top = -1000
      Since planets has 3 possible images(you could down load planet images from the following link, http://www.torontokidscomputer.com/code/pygame/
      you need initialize the planet with a random image.
      
      update(self) - It will move down by 2px every time call the update method. 
      If Bottom of the image reaches 1000, the new random planet will starts from a random centerx position, and top = -1000

   2. create planet sprite and call the update() method in the main program. so planet can appear on the screen and start move down.