Draw Tree Function
==================

Goals
-----
- Draw a tree
- Draw two trees
- Reference every position to single ``(x, y)`` point
- Define the ``draw_tree`` function
- Vary the ``y`` position. Need to create a list *outside* the game loop.

Starter code
------------

- :doc:`pygame-template`

What you need to do
-------------------

- Make a blue background
- Move the trees down and draw a single cloud (composed of multiple circles)
- Extract an x and y coordinate for the cloud and have every circle reference that point.
- Define a draw_cloud function that takes an x and y value.
- Draw multiple clouds in the sky
- Create a list for the cloud locations. And use this list to draw the clouds (with a for loop).
- In the game updates section, loop through the cloud locations and update only the x component (+= 3).
  Also in this loop, to prevent the clouds from traveling too far off screen, reset the x position if
  it goes too far.

Final Code
----------

.. code-block:: python
    :linenos:
    :emphasize-lines: 7-9, 53

    import random

    import pygame
    from pygame.locals import K_ESCAPE, KEYDOWN, QUIT


    def draw_tree(x: int, y: int):
        pygame.draw.rect(screen, (150,75,0), (x, y, 25, 150))          # trunk
        pygame.draw.circle(screen, (0, 175, 0), (x + 12, y - 50), 75)  # leaves


    pygame.init()

    WIDTH = 640
    HEIGHT = 480
    SIZE = (WIDTH, HEIGHT)

    screen = pygame.display.set_mode(SIZE)
    clock = pygame.time.Clock()

    # ---------------------------
    # Initialize global variables

    tree_locations = []

    for x in range(50, WIDTH, 50):
        y = 200 + random.randrange(-20, 20)
        location = [x, y]
        tree_locations.append(location)

    # ---------------------------

    running = True
    while running:
        # EVENT HANDLING
        for event in pygame.event.get():
            if event.type == KEYDOWN:
                if event.key == K_ESCAPE:
                    running = False
            elif event.type == QUIT:
                running = False
        
        # GAME STATE UPDATES

        # DRAWING
        screen.fill((255, 255, 255))  # always the first drawing command

        
        for location in tree_locations:
            x = location[0]
            y = location[1]

            draw_tree(x, y)


        # Must be the last two lines
        # of the game loop
        pygame.display.flip()
        clock.tick(30)
        #---------------------------


    pygame.quit()