public static Entity createExplosion(World world, float x, float y) {
Entity e = world.createEntity();
e.addComponent(new Transform(x, y));
e.addComponent(new SpatialForm("explosion"));
e.addComponent(new Expiration(200));
e.addToWorld();
return e;
}
public static Entity createBullet(World world, float x, float y, float angle, Entity shooter) {
Entity e = world.createEntity();