/** Internal routine for generating the List of particles on collision. */
public static ArrayList<Particle> generateParticles(Ball ball, Body body) {
double centerX = ball.getCenter().x();
double centerY = ball.getCenter().y();
double speed =
ball.getVelocity().magnitude() * ((body != null) ? (body.getRadius() / 100.0) : 1);
if (speed < .50) speed = .50;
if (speed > 2.50) speed = 2.50;
if (body != null) {
double max = Math.pow(body.getRadius() + ball.getRadius(), 2);
while (body.getCenter().distanceSquared(new Point2d(centerX, centerY)) < max) {
centerX -= ball.getVelocity().xComponent();
centerY -= ball.getVelocity().yComponent();
}
}
ArrayList<Particle> particles = new ArrayList<Particle>();
int num = (int) (300 * speed);
if (num < 150) num = 150;
else if (num > 400) num = 400;
for (int i = 0; i < num; i++) {
double angle = (Math.random() * 2 * Math.PI);
double xSpeed = 0.75 * (Math.random() * speed * Math.cos(angle));
double ySpeed = 0.75 * (Math.random() * speed * Math.sin(angle));
Color c;
double rand = Math.random();
if (body == null) c = CalcHelp.getShiftedColor(ball.getColor(), 100);
else if (rand < 0.3) c = CalcHelp.getShiftedColor(body.getColor(), 100);
else if (rand < 0.40) c = CalcHelp.getShiftedColor(new Color(230, 130, 70), 100);
else c = CalcHelp.getShiftedColor(ball.getColor(), 100);
Particle newParticle = new Particle(centerX, centerY, xSpeed, ySpeed, c);
particles.add(newParticle);
}
return particles;
}