Processing之旅-----【给鱼插上翅膀，Processing基础扩展库2】
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//**
* This is a relatively simple file player that lets you scrub forward and backward in an audio file.<br />
* It should be noted that it's not *exactly* scrubbing because the playback speed is not changed,
* it's simply that the position in the song is changed by very small increments when fast-forwarding or rewinding.
* But the end result is convincing enough.
* <p>
* The positioning code is inside of the Play, Rewind, and Forward classes, which are in button.pde.
*/
import ddf.minim.*;
Minim minim;
AudioPlayer song;
Play play;
Rewind rewind;
Forward ffwd;
void setup()
{
size(512, 200, P3D);
minim = new Minim(this);
// load a file from the data folder, use a sample buffer of 1024 samples
song = minim.loadFile("fair1939.wav", 512);
// buttons for control
play = new Play(width/2 - 50, 130, 20, 10);
rewind = new Rewind(width/2, 130, 20, 10);
ffwd = new Forward(width/2 + 50, 130, 20, 10);
}
void draw()
{
background(0);
// draw the wave form
// this wav is MONO, so we only need the left channel,
// though we could have used the right channel and gotten the same values
stroke(255);
for (int i = 0; i < song.bufferSize() - 1;i++)
{
line(i, 50 - song.left.get(i)*50, i+1, 50 - song.left.get(i+1)*10);
}
// draw the position in the song
// the position is in milliseconds,
// to get a meaningful graphic, we need to map the value to the range
float x = map(song.position(), 0, song.length(), 0, width);
stroke(255, 0, 0);
line(x, 50 - 20, x, 50 + 20);
// do the controls
play.update();
play.draw();
rewind.update();
rewind.draw();
ffwd.update();
ffwd.draw();
}
void mousePressed()
{
play.mousePressed();
rewind.mousePressed();
ffwd.mousePressed();
}
void mouseReleased()
{
play.mouseReleased();
rewind.mouseReleased();
ffwd.mouseReleased();
}
abstract class Button
{
int x, y, hw, hh;
Button(int x, int y, int hw, int hh)
{
this.x = x;
this.y = y;
this.hw = hw;
this.hh = hh;
}
boolean pressed()
{
return mouseX > x - hw && mouseX < x + hw && mouseY > y - hh && mouseY < y + hh;
}
abstract void mousePressed();
abstract void mouseReleased();
abstract void update();
abstract void draw();
}
class Play extends Button
{
boolean play;
boolean invert;
Play(int x, int y, int hw, int hh)
{
super(x, y, hw, hh);
play = true;
}
// code to handle playing and pausing the file
void mousePressed()
{
if ( pressed() )
{
invert = true;
if ( song.isPlaying() )
{
song.pause();
play = true;
}
else
{
song.loop();
play = false;
}
}
}
void mouseReleased()
{
invert = false;
}
// play is a boolean value used to determine what to draw on the button
void update()
{
if ( song.isPlaying() ) play = false;
else play = true;
}
void draw()
{
if ( invert )
{
fill(255);
stroke(0);
}
else
{
noFill();
stroke(255);
}
rect(x - hw, y - hh, hw*2, hh*2);
if ( invert )
{
fill(0);
stroke(255);
}
else
{
fill(255);
noStroke();
}
if ( play )
{
triangle(x - hw/3, y - hh/2, x - hw/3, y + hh/2, x + hw/2, y);
}
else
{
rect(x - hw/3, y - hh/2, hw/4, hh);
rect(x + hw/8, y - hh/2, hw/4, hh);
}
}
}
class Rewind extends Button
{
boolean invert;
boolean pressed;
Rewind(int x, int y, int hw, int hh)
{
super(x, y, hw, hh);
invert = false;
}
// code used to scrub backward in the file
void update()
{
// if the rewind button is currently being pressed
if (pressed)
{
// get the current song position
int pos = song.position();
// if it greater than 200 milliseconds
if ( pos > 200 )
{
// rewind the song by 200 milliseconds
song.skip(-200);
}
else
{
// if the song hasn't played more than 100 milliseconds
// just rewind to the beginning
song.rewind();
}
}
}
void mousePressed()
{
pressed = pressed();
if ( pressed )
{
invert = true;
// if the song isn't currently playing, rewind it to the beginning
if ( !song.isPlaying() ) song.rewind();
}
}
void mouseReleased()
{
pressed = false;
invert = false;
}
void draw()
{
if ( invert )
{
fill(255);
stroke(0);
}
else
{
noFill();
stroke(255);
}
rect(x - hw, y - hh, hw*2, hh*2);
if ( invert )
{
fill(0);
stroke(255);
}
else
{
fill(255);
noStroke();
}
triangle(x - hw/2, y, x, y - hh/2, x, y + hh/2);
triangle(x, y, x + hw/2, y - hh/2, x + hw/2, y + hh/2);
}
}
class Forward extends Button
{
boolean invert;
boolean pressed;
Forward(int x, int y, int hw, int hh)
{
super(x, y, hw, hh);
invert = false;
}
void update()
{
// if the forward button is currently being pressed
if (pressed)
{
// get the current position of the song
int pos = song.position();
// if the song's position is more than 40 milliseconds from the end of the song
if ( pos < song.length() - 40 )
{
// forward the song by 40 milliseconds
song.skip(40);
}
else
{
// otherwise, cue the song at the end of the song
song.cue( song.length() );
}
// start the song playing
song.play();
}
}
void mousePressed()
{
pressed = pressed();
if ( pressed )
{
invert = true;
}
}
void mouseReleased()
{
pressed = false;
invert = false;
}
void draw()
{
if ( invert )
{
fill(255);
stroke(0);
}
else
{
noFill();
stroke(255);
}
rect(x - hw, y - hh, hw*2, hh*2);
if ( invert )
{
fill(0);
stroke(255);
}
else
{
fill(255);
noStroke();
}
triangle(x, y, x - hw/2, y - hh/2, x - hw/2, y + hh/2);
triangle(x, y - hh/2, x, y + hh/2, x + hw/2, y);
}
}
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。
谢谢楼主，学习了。
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