protected Entity createAsteroid (Size sz, float x, float y, float vx, float vy) {
Entity ast = create(true);
ast.add(type, size, sprite, opos, pos, vel, spin, radius);
float side = sz.size;
int iidx = rando.getInt(8);
float ah = asteroids.height();
ImageLayer layer = new ImageLayer(asteroids.region(iidx*ah, 0, ah, ah));
layer.setOrigin(ah/2, ah/2);
layer.setScale(side/ah);
layer.setRotation(rando.getFloat(MathUtil.TAU));
int id = ast.id;
type.set(id, ASTEROID);
size.set(id, sz);
sprite.set(id, layer);
spin.set(id, rando.getInRange(-MAXSPIN, MAXSPIN));
opos.set(id, x, y);
pos.set(id, x, y);
vel.set(id, vx, vy);
radius.set(id, side*0.425f);
return ast;
}