addImpulse method
Changes body's velocity at once (N·s).
Implementation
@override
void addImpulse(int body, Vector3 impulse) {
final b = bodies[body];
if (b == null || b.type != BodyType3D.dynamic) return;
b.linearVelocity.addScaled(impulse, 1 / b.mass);
_wake(b);
}