Sparkler.java

// for processing program.

import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.effects.*;
import ddf.minim.signals.*;
import ddf.minim.spi.*;
import ddf.minim.ugens.*;
import com.jogamp.opengl.GL;
import com.jogamp.opengl.GL2ES2;

Minim minim;
AudioPlayer player;
PImage img;
FFT fft;
int specSize;
float volume;
int BUFSIZE = 512;
GL2ES2 gl;

float[] posX = new float[BUFSIZE];
float[] posY = new float[BUFSIZE];
float[] speedX = new float[BUFSIZE];
float[] speedY = new float[BUFSIZE];
float[] angle = new float[BUFSIZE];

float stiffness = 0.6;
float damping = 0.9;
float mass = 6.0;


void setup(){
  size(854, 480, OPENGL);
  minim = new Minim(this);
  player = minim.loadFile("04.mp3",BUFSIZE);　// path to music file.
  fft = new FFT(player.bufferSize(), player.sampleRate());
  fft.window(FFT.HAMMING);
  colorMode(HSB, 360, 100, 100, 100);
  noStroke();
  player.play();
  frameRate(14);

  PGraphicsOpenGL pg = (PGraphicsOpenGL)g;
  PGL pgl = beginPGL();  
  gl = ((PJOGL)pgl).gl.getGL2ES2();
  gl.setSwapInterval(1);
  endPGL();
  
  for (int i = 0; i < BUFSIZE; i++) {
    posX[i] = 0;
    posY[i] = 0;
    speedX[i] = 0;
    speedY[i] = 0;
    angle[i] = radians(random(0, 360));
  }
  background(0);
}

void drawEllipse(int xOffset){
  specSize = fft.specSize();
  for(int i = 0; i < specSize; i++){
     float h = map(i, 0, specSize, 0, 180);
     float ellipseSize = map(fft.getBand(i), 0, BUFSIZE/16, 0, width);
     float x = map(i, 0, specSize, width/2, xOffset);
     float w = width/float(specSize)/2;
     fill(h, 80,80,7);
     ellipse(x, height/2, ellipseSize, ellipseSize); 
  }  
}

void drawGLSpring(){
  background(0);
  backgroundFade();
  
  gl.glBlendFunc(GL2ES2.GL_SRC_ALPHA, GL2ES2.GL_ONE);
  
  translate(width/2, height/2);
  fft.forward(player.mix);
  float specSize = fft.specSize();
  float getBand;
  
  for (int i = 0; i < specSize; i++){
     getBand = fft.getBand(i);
    float addFroce = getBand* i * width/float(BUFSIZE)/2.0;
    float direction = radians(random(0, 360));
    float addX = cos(direction) * addFroce;
    float addY = sin(direction) * addFroce;

    
    float forceX = stiffness * -posX[i] + addX;
    float accelerationX = forceX / mass;
    speedX[i] = damping * (speedX[i] + accelerationX);
    float forceY = stiffness * -posY[i] + addY;
    float accelerationY = forceY / mass;
    speedY[i] = damping * (speedY[i] + accelerationY);
    posX[i] += speedX[i];
    posY[i] += speedY[i];

    fill(255, 20);
    float h = map(i, 0, specSize, 0, 360);
    float r = getBand * i / 4.0 + 30.0;
    fill(h, 100, 100, 10);
    ellipse(posX[i], posY[i], r, r);
  }
}

void draw()
{
  drawGLSpring();
}

void stop(){
   player.close();
   minim.stop();
   super.stop(); 
}

void backgroundFade() {
  gl.glBlendFunc(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA);
  gl.glBlendEquation(GL.GL_FUNC_ADD);

  noStroke();
  
  fill(0, 5);
  
  rect(0, 0, width, height);
}