//(c) Rory Clune 02/10/2011
//Bouncing ball with cor < 1 and frictional energy loss

float posX, posY, theta;
float velX, velY, angVel;
int radius = 50;
float crN = 0.8;
float crT = 0.1; 

//Sound
import ddf.minim.*;
Minim minim;
AudioSample bounce;

void setup() 
{
  size(600, 400);
  noStroke();
  frameRate(100);
  smooth();
  posX = width/2; posY = height/2;
  velX = 0; velY = 30; angVel = 0.5;
  //Sound:
  minim = new Minim(this);
  bounce = minim.loadSample("ball.mp3", 128);
}
void draw() 
{  
  background(40,40,40);
  velY += 0.08;
  posX += velX; posY += velY;
  theta += angVel;
  if ((theta>0)&&(theta>2*PI)){
    theta-=2*PI;
  }
  if ((posX - radius < 0)||(posX > width-radius)){
    velX *= -1*crN;
    float newVelY = 0.9*((1-0.4*crT)*velY+0.4*(1+crT)*radius*angVel)/1.4;
    float newAngVel = 0.9*((1+crT)*velY+(0.4-crT)*radius*angVel)/(radius*1.4);
    velY = newVelY;
    angVel = newAngVel;
    if (posX - radius < 0){posX = radius;}
    else if(posX > width-radius){posX = width-radius;}
    if(abs(velX) > 0.1){
        bounce.trigger();
    }
  }
  if ((posY > height-radius)||(posY - radius < 0)){
    velY *= -1*crN;
    float newVelX = 0.9*((1-0.4*crT)*velX+0.4*(1+crT)*radius*angVel)/1.4;
    float newAngVel = 0.9*((1+crT)*velX+(0.4-crT)*radius*angVel)/(radius*1.4);
    velX = newVelX;
    angVel = newAngVel;
    if(posY > height-radius){posY = height-radius;}
    else if (posY - radius < 0){posY = radius;}
    if(abs(velY) > 0.1){
        bounce.trigger();        
    }
  }  
  stroke(253);
  ellipse(posX, posY, 2*radius, 2*radius);
  stroke(126); 
  line(posX + radius*cos(theta), posY + radius*sin(theta), posX - radius*cos(theta), posY - radius*sin(theta));
  strokeWeight(4);
}