> I dunno, I''m a little skeptical about the integer precision thing, as I''ve never seen that effect purely due to that before.

As I said, Asteroids with non-rotating rocks is just about the worst-case scenario I can imagine for this. In most other cases that I can think of, integer precision would not be nearly as noticeable, it would be hidden in the noise.

> and it still *should* happen in D3D, even if that is the problem, since I don''t think it does anything more to blend edges to smooth out the motion

I can''t parse this fully, but it certainly should not happen in D3D. Move a sprite 1/10th of a pixel and it *will* look different, I promise you -- as long as you''re not using point sampling. In DirectDraw it has to cross the pixel quantum before there''s a change in appearance.

Now if were untextured or if in some other way you could see the edges, that would be a different story. You would need another form of antialiasing like supersampling or multisampling.