// Handles all ball-ball collisions
void handleBallBallCollisions() {
for (int i = 0; i < _scene.numChildren(); i++)
for (int j = 0; j < _scene.numChildren(); j++) {
if (i == j) continue;
Object3d b1 = _scene.getChildAt(i);
Object3d b2 = _scene.getChildAt(j);
// if (b1 == _room || b2 == _room)
// continue;
if (testBallBallCollision(b1, b2)) {
// Make the balls reflect off of each other
Number3d displacement = Number3d.subtract(b1.position(), b2.position());
displacement.normalize();
float objDot = Number3d.dot(b1.velocity(), displacement);
displacement.multiply(objDot);
displacement.multiply(2f);
b1.velocity().subtract(displacement);
displacement = Number3d.subtract(b1.position(), b2.position());
displacement.normalize();
objDot = Number3d.dot(b2.velocity(), displacement);
displacement.multiply(objDot);
displacement.multiply(2f);
b2.velocity().subtract(displacement);
}
}
}
// Returns whether two balls are colliding
boolean testBallBallCollision(Object3d obj1, Object3d obj2) {
// Check whether the balls are close enough
float r = obj1.radius() + obj2.radius();
Number3d obj1Clone = Number3d.subtract(obj1.position(), obj2.position());
obj1Clone.subtract(obj2.position());
if (obj1Clone.magnitudeSquared() < r * r) {
// Check whether the balls are moving toward each other
Number3d netVelocity = Number3d.subtract(obj1.velocity(), obj2.velocity());
Number3d displacement = Number3d.subtract(obj1.position(), obj2.position());
return Number3d.dot(netVelocity, displacement) < 0;
} else return false;
}