I have a program I'm working on that uses the Beads library to sample songs and change the rate at which they're played (this is done using a potentiometer—I'm sending data in from an Arduino to control the rate).

In this program, the sound clip is established in the void setup() function.

However, I would like to be able to change the song sample dynamically, in void draw(), depending on what data the program is receiving. I have five different songs, and I want the Processing program to play a different song, depending on whether the values it's receiving are between 1-100, 101-200, 201-300, 301-400, or 401-500.

Here is my code so far:

2. import processing.serial.*;
3. 
   
4. Serial port;
5. 
   
6. float derp = 0;
7. 
   
8. // Sampling_03.pde
9. 
   
10. // this is a more complex sampler
11. // clicking somewhere on the window initiates sample playback
12. // moving the mouse controls the playback rate
13. 
    
14. import beads.*;
15. 
    
16. AudioContext ac;
17. 
    
18. SamplePlayer sp1;
19. 
    
20. // we can run both SamplePlayers through the same Gain
21. Gain sampleGain;
22. Glide gainValue;
23. 
    
24. Glide rateValue;
25. 
    
26. void setup()
27. {
28.   size(800, 600);
29. 
    
30.   port = new Serial(this, "/dev/tty.usbmodem411", 9600);
31.   port.bufferUntil('\n');
32. 
    
33.   ac = new AudioContext(); // create our AudioContext
34. 
    
35.     // whenever we load a file, we need to enclose the code in a Try/Catch block
36.   // Try/Catch blocks will inform us if the file can't be found
37.   try {  
38.     // initialize the SamplePlayer
39.     sp1 = new SamplePlayer(ac, new Sample(sketchPath("") + "prelude_no_8.mp3"));
40.   }
41.   catch(Exception e)
42.   {
43.     // if there is an error, show an error message (at the bottom of the processing window)
44.     println("Exception while attempting to load sample!");
45.     e.printStackTrace(); // then print a technical description of the error
46.     exit(); // and exit the program
47.   }
48. 
    
49.   // note that we want to play the sample multiple times
50.   sp1.setKillOnEnd(false);
51. 
    
52.   rateValue = new Glide(ac, 1, 30); // initialize our rateValue Glide object
53.   sp1.setRate(rateValue); // connect it to the SamplePlayer
54. 
    
55.   // as usual, we create a gain that will control the volume of our sample player
56.   gainValue = new Glide(ac, 0.0, 30);
57.   sampleGain = new Gain(ac, 1, gainValue);
58.   sampleGain.addInput(sp1);
59. 
    
60.   ac.out.addInput(sampleGain); // connect the Gain to the AudioContext
61. 
    
62.   ac.start(); // begin audio processing
63. 
    
64.   background(0); // set the background to black
65.   stroke(255);
66.   line(width/2, 0, width/2, height); // draw a line in the middle
67.   text("Click to begin playback.", 100, 100); // tell the user what to do!
68.   text("Move the mouse to control playback speed.", 100, 120); // tell the user what to do!
69. }
70. 
    
71. // although we're not drawing to the screen, we need to have a draw function
72. // in order to wait for mousePressed events
73. void draw()
74. {
75.   
76.   float halfWidth = width / 2.0;
77. 
    
78.   gainValue.setValue((float)mouseY / (float)height); // set the gain based on mouse position along the Y-axis
79.   rateValue.setValue(((float)derp - halfWidth)/halfWidth); // set the rate based on mouse position along the X-axis
80. 
    
81.   print("gain:");
82.   println((float)mouseY / (float)height);
83.   print("rate:");
84.   println(((float)derp - halfWidth)/halfWidth);
85.   print("derp:");
86.   println(derp);
87. }
88. 
    
89. // this routine is called whenever a mouse button is pressed on the Processing sketch
90. void mousePressed()
91. {
92.   // if the left mouse button is clicked, then play the sound
93.   if( mouseX > width / 2.0 )
94.   {
95.     sp1.setPosition(000); // set the start position to the beginning
96.     sp1.start(); // play the audio file
97.   }
98.   // if the right mouse button is clicked, then play the bass drum sample backwards
99.   else 
100.   {
101.     sp1.setToEnd(); // set the start position to the end of the file
102.     sp1.start(); // play the file in reverse (rate set in the draw routine)
103.   }
104. }
105. 
     
106. void serialEvent (Serial port)
107. {
108.   derp = float(port.readStringUntil('\n'));
109. }

Any help would be largely appreciated! Thank you!