// 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;
}
void checkWallCollision(Object3d obj, Wall wall, double elapsed) {
if (testBallWallCollision(obj, wall)) {
// Make the ball reflect off of the wall
Number3d dir = wallDirection(wall);
dir.normalize();
float objDot = Number3d.dot(obj.velocity(), dir);
dir.multiply(objDot);
dir.multiply(2f);
obj.velocity().subtract(dir);
Object3d.applyImpactCORSolid(obj);
}
}
boolean testBallWallCollision(Object3d obj, Wall wall) {
Number3d dir = wallDirection(wall);
// Check whether the ball is far enough in the "dir" direction, and whether
// it is moving toward the wall
switch (wall) {
case WALL_BOTTOM:
return obj.position().y < PERIM_BOTTOM && Number3d.dot(obj.velocity(), dir) > 0;
case WALL_TOP:
return obj.position().y > PERIM_TOP && Number3d.dot(obj.velocity(), dir) > 0;
case WALL_LEFT:
return obj.position().x < PERIM_LEFT && Number3d.dot(obj.velocity(), dir) > 0;
case WALL_RIGHT:
return obj.position().x > PERIM_RIGHT && Number3d.dot(obj.velocity(), dir) > 0;
case WALL_NEAR:
return obj.position().z > PERIM_NEAR && Number3d.dot(obj.velocity(), dir) > 0;
case WALL_FAR:
return obj.position().z < PERIM_FAR && Number3d.dot(obj.velocity(), dir) > 0;
}
return false;
}