Creating a Noise Loop

In PyGame, you can load several sounds at once. In this program (see Figure 9-2), you’ll create a loop that plays sounds. Every fourth time the loop repeats it will play a different sound. By adapting the program, you can make music or drum loops.

1. Open IDLE and create a new file with File⇒New Window.
2. Save the program as noiseLoop.py in the Adventure 9 folder.
3. First add these two statements to allow the program to use PyGame:

   import pygame
pygame.init()

4. The next statement creates the clock. Although the program doesn’t use a window or animations, it still uses the clock. The clock will determine how fast the sounds play later in the program. Add this to your program:

   clock = pygame.time.Clock()

5. You’re going to use two sounds in this program, crash.wav and hit.wav. The program now needs to load these sounds:

   crash = pygame.mixer.Sound('crash.wav')
hit = pygame.mixer.Sound('hit.wav')

6. The next part of the program creates the count and the loop. The loop limits the number of times it repeats so that it only plays 200 sounds before closing:

   count = 0
while count < 200:

7. As the loop repeats, the crash sound will play every fourth repeat in the loop. The next bit of code controls this:

       if count % 4 == 0:
        crash.play()

8. The hit sound will play whenever the crash sound doesn’t play—in other words, three times every loop:

       else:
        hit.play()

9. The last lines of the code increase the count every time the loop repeats and limit the speed that the loop repeats. In this case, it will repeat twice a second:

       count += 1
    clock.tick(2)

10. Save the program and run it using Run⇒Run Module.
11. When the program starts running it plays the sounds in a loop. What does it sound like? Every fourth sound should be a crash, and the other three should be hit sounds.

Making Keyboard Sound Effects

In this program, you’ll use the keyboard to control sounds (see Figure 9-3). When you press the a or s key, it will play a sound. You can add your own sounds and keys by extending the program.

Adding sounds when keys are pressed is used in many video games. For example, in fantasy adventure games characters make a noise when they swing their sword, fire their bow or cast a spell.

1. Open IDLE and create a new file with File⇒New Window.
2. Save the program as keyboardSounds.py in the Adventure 9 folder.
3. Add the first two lines to the program that allow it to use PyGame in the program:

   import pygame
pygame.init()

4. This program uses a window, as it also uses the keyboard, so set up the window now with this code:

   windowSize = [400, 300]
pygame.display.set_mode(windowSize)

5. Now you’re ready to load the sounds:

   hit = pygame.mixer.Sound("hit.wav")
crash = pygame.mixer.Sound("crash.wav")

6. This code starts the game loop:

   done = False
while not done:

7. The next bit of code checks if keys are pressed and plays the sounds if they are:

       keys = pygame.key.get_pressed()

    if keys[pygame.K_a]:
        hit.play()

    if keys[pygame.K_s]:
        crash.play()

8. Now add the code to manage the closing of the window:

       for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True
pygame.quit()

9. Save the program and run it using Run⇒Run Module.
10. When the window opens, click on it and press the a and s keys. You should hear the hit and crash sounds. Have some fun with that, but watch out—if you press the keys really quickly, sometimes the sound won’t play.

Playing Music

This first program will get you used to using music with PyGame and Python (see Figure 9-4). It will play a single music file. Like the sound programs you created earlier, it won’t open a window when the program runs.

1. Open IDLE and create a new file with File⇒New Window.
2. Save the program as music.py in the Adventure 9 folder.
3. First you need to add the two statements that allow the program to use PyGame:

   import pygame
pygame.init()

4. The next part of the program loads the music and plays it:

   pygame.mixer.music.load("music.mp3")
pygame.mixer.music.play()

5. Just like playing the sounds earlier, the program will close instantly before the music plays unless you add some code to keep it open. This next piece of code uses a loop to make the program stay open while the music is playing:

   while pygame.mixer.music.get_busy():
    pygame.time.wait(200)

6. Save the program and run it using Run⇒Run Module.
7. When the program starts, it will play the music once and then close.

Adding Volume Tremolo

Next, you’re going to add tremolo to some music (see Figure 9-5).

Tremolo has many uses in music. If the speed of the effect is really fast, it sounds choppy. Effects like this have some use in computer games. Tremolos can be used to make things sound spooky or exciting, depending on the speed.

1. Open IDLE and create a new Python program with File⇒New Window.
2. Save the program as tremolo.py in the Adventure 9 folder.
3. Click in the file editor and add this code to allow your program to use PyGame and the math module. The math module is used later in the program to add the tremolo wobble to the music:

   import math
import pygame
pygame.init()

4. The next part of the program loads and plays the music:

   pygame.mixer.music.load("music.mp3")
pygame.mixer.music.play()

5. This part of the program starts the loop that applies the tremolo wobble to the music. The count isn’t used to control the number of times the loop repeats, but instead is used to set the level of the volume in the tremolo:

   count = 0
while pygame.mixer.music.get_busy():

6. Inside the loop, the volume level is determined using the first statement in this code. The sin() function creates the wave used to set the volume and the abs() function makes sure the value is positive:

       volume = abs(math.sin(count))

7. Next, the volume is set and there is a delay before the next loop starts:

   pygame.mixer.music.set_volume(volume)
    count += 0.2
    pygame.time.delay(200)

8. Save the program and run it using Run⇒Run Module.
9. When the program starts the music will play, with the volume increasing and decreasing in a wave.

Making a Music Player

Now for something really exciting. In this next program you’ll use Tkinter and PyGame together to make a music player (see Figure 9-6). Your program will create a GUI that allows you to play and pause a song using a button and control its volume with a slider.

1. Start as usual by opening IDLE and creating a new file with File⇒New Window.
2. Save the program as musicPlayer.py in the Adventure 9 folder.
3. The first part of the program allows it to use PyGame and Tkinter. This code is no different to the code you’d use for PyGame or Tkinter individually:

   import pygame
import Tkinter as tk
window = tk.Tk()
pygame.init()

4. Next up, add this statement to the program to load the music file:

   pygame.mixer.music.load("music.mp3")

5. The next two variables are used later in the program to check whether the music has started playing and whether the music is paused. As the music hasn’t started at this point in the program, both of the variables are set to False:

   started = False
playing = False

6. So that the button in the program can run code when it is clicked, this program includes these functions to check if the music has started, is playing or has been paused, then plays or pauses the music. The first part of the program makes the playing and started variables global so that the function can change their values:

   def buttonClick():
    global playing, started

7. The next part of the function checks if the music is not playing. This means that the music is either paused or hasn’t started playing yet:

       if not playing:

8. In the next bit of code, if the music hasn’t started playing yet (in other words, the Play button hasn’t been clicked yet), the program will start to play the music:

           if not started:
            pygame.mixer.music.play(-1)
            started = True

9. If the music has started playing but isn’t currently playing, the music must therefore be paused. This code will un-pause the music:

           else:
            pygame.mixer.music.unpause()

10. When the music is paused, this piece of code changes the text on the button to Pause:

            button.config(text="Pause")

11. If the music is playing, the next piece of code changes the button’s text to Play and pauses the music when the button is next pressed:

        else:
        pygame.mixer.music.pause()
        button.config(text="Play")

12. The next bit of code either stops or starts the music, depending on if it was or wasn’t playing already. If it was True (it was playing), it will be swapped to False (stops playing) and vice versa.

    playing = not playing

13. The next function changes the volume when the slider updates. You’re going to create a volume slider in the next step, which returns a number between 0 and 100—but the volume_set() function requires a number between 0 and 1. For that reason, the last statement in this function divides the slider’s value by 100 so that it is the right size:

    def setVolume(val):
    volume = float(slider.get())
    pygame.mixer.music.set_volume(volume / 100)

14. Next, you need to create the button and the slider for the program. For this, a Tkinter button and a Tkinter scale object are used. While it’s possible to make these things in PyGame, they have already been built into Tkinter to make it much quicker and easier for you to use them:

    slider = tk.Scale(window, from_=100, to=0, command=setVolume)
button = tk.Button(window, text="Play", command=buttonClick)

15. Finally, this piece of code adds the slider and button to the window and starts the Tkinter main loop:

    slider.pack()
slider.set(100)
button.pack()
window.mainloop()

16. Save the program and run it using Run⇒Run Module.
17. It’s time to test your handiwork! Click the buttons to play and pause the music and change the volume with the slider.