Sound and Images - Invent Your Own Computer Games with Python - page 365

19 - Sound and Images
track of where and how big the player is. The player variable doesn't contain the
player's image, just the player's size and location. At the beginning of the program, the top
left corner of the player will be located at (300, 100) and the player will have a height and
width of 40 pixels to start.
The second variable that represents the player will be playerImage . The
pygame.image.load() function is passed a string of the filename of the image to
load. The return value of pygame.image.load() is a Surface object that has the
image in the image file drawn on its surface. We store this Surface object inside of
playerImage .
The pygame.transform.scale() Function
On line 20, we will use a new function in the pygame.transform module. The
pygame.transform.scale() function can shrink or enlarge a sprite. The first
argument is a pygame.Surface object with the image drawn on it. The second
argument is a tuple for the new width and height of the image in the first argument. The
pygame.transform.scale() function returns a pygame.Surface object with the
image drawn at a new size. We will store the original image in the playerImage
variable but the stretched image in the playerStretchedImage variable.
On line 21, we call pygame.image.load() again to create a Surface object with
the cherry image drawn on it.
Be sure that you have the player.png and cherry.png file in the same directory as the
spritesAndSounds.py file, otherwise Pygame will not be able to find them and will give an
error.
The Surface objects that are stored in playerImage and foodImage are the same
as the Surface object we use for the window. In our game, we will blit these surfaces
onto the window's surface to create the window that the user sees. This is exactly the same
as the when we got a Surface object returned from the render() method for Font
objects in our Hello World program. In order to actually display the text, we had to blit this
Surface object (which the text was drawn on) to the window's Surface object. (And
then, of course, call the update() method on the window's Surface object.)
Setting Up the Music and Sounds
37. # set up music
38. pickUpSound = pygame.mixer.Sound('pickup.wav')
39. pygame.mixer.music.load('background.mid')
40. pygame.mixer.music.play(-1, 0.0)
41. musicPlaying = True
Next we need to load the sound files. There are two modules for sound in Pygame. The