Processing之旅-----【给鱼插上翅膀，Processing基础扩展库2】

yangfanconan

下面我们继续学习Processing自带的库---minim ，这是一个音频处理库，怎么说功能十分强大，官网是http://code.compartmental.net/tools/minim/

1. /**
   
2.   * This is a relatively simple file player that lets you scrub forward and backward in an audio file.<br />
   
3.   * It should be noted that it's not *exactly* scrubbing because the playback speed is not changed,
   
4.   * it's simply that the position in the song is changed by very small increments when fast-forwarding or rewinding.
   
5.   * But the end result is convincing enough.
   
6.   * <p>
   
7.   * The positioning code is inside of the Play, Rewind, and Forward classes, which are in button.pde.
   
8.   */
   
9. 
   
10. import ddf.minim.*;
    
11. 
    
12. Minim minim;
    
13. AudioPlayer song;
    
14. Play play;
    
15. Rewind rewind;
    
16. Forward ffwd;
    
17. 
    
18. void setup()
    
19. {
    
20.   size(512, 200, P3D);
    
21.   minim = new Minim(this);
    
22.   // load a file from the data folder, use a sample buffer of 1024 samples
    
23.   song = minim.loadFile("fair1939.wav", 512);
    
24.   // buttons for control
    
25.   play = new Play(width/2 - 50, 130, 20, 10);
    
26.   rewind = new Rewind(width/2, 130, 20, 10);
    
27.   ffwd = new Forward(width/2 + 50, 130, 20, 10);
    
28. }
    
29. 
    
30. void draw()
    
31. {
    
32.   background(0);
    
33.   // draw the wave form
    
34.   // this wav is MONO, so we only need the left channel,
    
35.   // though we could have used the right channel and gotten the same values
    
36.   stroke(255);
    
37.   for (int i = 0; i < song.bufferSize() - 1;  i++)
    
38.   {
    
39.     line(i, 50 - song.left.get(i)*50, i+1, 50 - song.left.get(i+1)*10);
    
40.   }
    
41.   // draw the position in the song
    
42.   // the position is in milliseconds,
    
43.   // to get a meaningful graphic, we need to map the value to the range [0, width]
    
44.   float x = map(song.position(), 0, song.length(), 0, width);
    
45.   stroke(255, 0, 0);
    
46.   line(x, 50 - 20, x, 50 + 20);
    
47.   // do the controls
    
48.   play.update();
    
49.   play.draw();
    
50.   rewind.update();
    
51.   rewind.draw();
    
52.   ffwd.update();
    
53.   ffwd.draw();
    
54. }
    
55. 
    
56. void mousePressed()
    
57. {
    
58.   play.mousePressed();
    
59.   rewind.mousePressed();
    
60.   ffwd.mousePressed();
    
61. }
    
62. 
    
63. void mouseReleased()
    
64. {
    
65.   play.mouseReleased();
    
66.   rewind.mouseReleased();
    
67.   ffwd.mouseReleased();
    
68. }

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1. abstract class Button
   
2. {
   
3.   int x, y, hw, hh;
   
4.   
   
5.   Button(int x, int y, int hw, int hh)
   
6.   {
   
7.     this.x = x;
   
8.     this.y = y;
   
9.     this.hw = hw;
   
10.     this.hh = hh;
    
11.   }
    
12.   
    
13.   boolean pressed()
    
14.   {
    
15.     return mouseX > x - hw && mouseX < x + hw && mouseY > y - hh && mouseY < y + hh;
    
16.   }
    
17.   
    
18.   abstract void mousePressed();
    
19.   abstract void mouseReleased();
    
20.   abstract void update();
    
21.   abstract void draw();
    
22. }
    
23. 
    
24. class Play extends Button
    
25. {
    
26.   boolean play;
    
27.   boolean invert;
    
28.   
    
29.   Play(int x, int y, int hw, int hh)
    
30.   {
    
31.     super(x, y, hw, hh);
    
32.     play = true;
    
33.   }
    
34.   
    
35.   // code to handle playing and pausing the file
    
36.   void mousePressed()
    
37.   {
    
38.     if ( pressed() )
    
39.     {
    
40.       invert = true;
    
41.       if ( song.isPlaying() )
    
42.       {
    
43.         song.pause();
    
44.         play = true;
    
45.       }
    
46.       else
    
47.       {
    
48.         song.loop();
    
49.         play = false;
    
50.       }
    
51.     }
    
52.   }
    
53.   
    
54.   void mouseReleased()
    
55.   {
    
56.     invert = false;
    
57.   }
    
58.   
    
59.   // play is a boolean value used to determine what to draw on the button
    
60.   void update()
    
61.   {
    
62.     if ( song.isPlaying() ) play = false;
    
63.     else play = true;
    
64.   }
    
65.   
    
66.   void draw()
    
67.   {
    
68.     if ( invert )
    
69.     {
    
70.       fill(255);
    
71.       stroke(0);
    
72.     }
    
73.     else
    
74.     {
    
75.       noFill();
    
76.       stroke(255);
    
77.     }
    
78.     rect(x - hw, y - hh, hw*2, hh*2);
    
79.     if ( invert )
    
80.     {
    
81.       fill(0);
    
82.       stroke(255);
    
83.     }
    
84.     else
    
85.     {
    
86.       fill(255);
    
87.       noStroke();
    
88.     }
    
89.     if ( play )
    
90.     {
    
91.       triangle(x - hw/3, y - hh/2, x - hw/3, y + hh/2, x + hw/2, y);
    
92.     }
    
93.     else
    
94.     {
    
95.       rect(x - hw/3, y - hh/2, hw/4, hh);
    
96.       rect(x + hw/8, y - hh/2, hw/4, hh);
    
97.     }
    
98.   }
    
99. }
    
100. 
     
101. class Rewind extends Button
     
102. {
     
103.   boolean invert;
     
104.   boolean pressed;
     
105.   
     
106.   Rewind(int x, int y, int hw, int hh)
     
107.   {
     
108.     super(x, y, hw, hh);
     
109.     invert = false;
     
110.   }
     
111.   
     
112.   // code used to scrub backward in the file
     
113.   void update()
     
114.   {
     
115.     // if the rewind button is currently being pressed
     
116.     if (pressed)
     
117.     {
     
118.       // get the current song position
     
119.       int pos = song.position();
     
120.       // if it greater than 200 milliseconds
     
121.       if ( pos > 200 )
     
122.       {
     
123.         // rewind the song by 200 milliseconds
     
124.         song.skip(-200);
     
125.       }
     
126.       else
     
127.       {
     
128.         // if the song hasn't played more than 100 milliseconds
     
129.         // just rewind to the beginning
     
130.         song.rewind();
     
131.       }
     
132.     }
     
133.   }
     
134.   
     
135.   void mousePressed()
     
136.   {
     
137.     pressed = pressed();
     
138.     if ( pressed )
     
139.     {
     
140.       invert = true;
     
141.       // if the song isn't currently playing, rewind it to the beginning
     
142.       if ( !song.isPlaying() ) song.rewind();      
     
143.     }
     
144.   }
     
145.   
     
146.   void mouseReleased()
     
147.   {
     
148.     pressed = false;
     
149.     invert = false;
     
150.   }
     
151. 
     
152.   void draw()
     
153.   {
     
154.     if ( invert )
     
155.     {
     
156.       fill(255);
     
157.       stroke(0);
     
158.     }
     
159.     else
     
160.     {
     
161.       noFill();
     
162.       stroke(255);
     
163.     }
     
164.     rect(x - hw, y - hh, hw*2, hh*2);
     
165.     if ( invert )
     
166.     {
     
167.       fill(0);
     
168.       stroke(255);
     
169.     }
     
170.     else
     
171.     {
     
172.       fill(255);
     
173.       noStroke();
     
174.     }
     
175.     triangle(x - hw/2, y, x, y - hh/2, x, y + hh/2);
     
176.     triangle(x, y, x + hw/2, y - hh/2, x + hw/2, y + hh/2);   
     
177.   }  
     
178. }
     
179. 
     
180. class Forward extends Button
     
181. {
     
182.   boolean invert;
     
183.   boolean pressed;
     
184.   
     
185.   Forward(int x, int y, int hw, int hh)
     
186.   {
     
187.     super(x, y, hw, hh);
     
188.     invert = false;
     
189.   }
     
190.   
     
191.   void update()
     
192.   {
     
193.     // if the forward button is currently being pressed
     
194.     if (pressed)
     
195.     {
     
196.       // get the current position of the song
     
197.       int pos = song.position();
     
198.       // if the song's position is more than 40 milliseconds from the end of the song
     
199.       if ( pos < song.length() - 40 )
     
200.       {
     
201.         // forward the song by 40 milliseconds
     
202.         song.skip(40);
     
203.       }
     
204.       else
     
205.       {
     
206.         // otherwise, cue the song at the end of the song
     
207.         song.cue( song.length() );
     
208.       }
     
209.       // start the song playing
     
210.       song.play();
     
211.     }
     
212.   }
     
213.   
     
214.   void mousePressed()
     
215.   {
     
216.     pressed = pressed();
     
217.     if ( pressed )
     
218.     {
     
219.       invert = true;      
     
220.     }
     
221.   }
     
222.   
     
223.   void mouseReleased()
     
224.   {
     
225.     pressed = false;
     
226.     invert = false;
     
227.   }
     
228. 
     
229.   void draw()
     
230.   {
     
231.     if ( invert )
     
232.     {
     
233.       fill(255);
     
234.       stroke(0);
     
235.     }
     
236.     else
     
237.     {
     
238.       noFill();
     
239.       stroke(255);
     
240.     }
     
241.     rect(x - hw, y - hh, hw*2, hh*2);
     
242.     if ( invert )
     
243.     {
     
244.       fill(0);
     
245.       stroke(255);
     
246.     }
     
247.     else
     
248.     {
     
249.       fill(255);
     
250.       noStroke();
     
251.     }
     
252.     triangle(x, y, x - hw/2, y - hh/2, x - hw/2, y + hh/2);
     
253.     triangle(x, y - hh/2, x, y + hh/2, x + hw/2, y);   
     
254.   }  
     
255. }

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以上是一个官方的例子，很多minim的功能都要参照其官网的文档。

举一个比较使用的例子
如果游戏中我们想处理一个音效，让它只出现一次，song.loop(0);就可以了。不用搞太复杂。

laozjx

谢谢楼主，学习了。