You could probably deal with this by using a little extra space in the texture atlas I don't know how well non-power-of two texture coordinates work in GLES an

You could probably deal with this by using a little extra space in the texture atlas I don't know how well non-power-of two texture coordinates work in GLES and WebGL, but you could put a single column of pixels from the other side of the texture on both sides. say you have ABCD and so you store, DABCDA, it'd use up some memory but could result in a speed boost since you could likely avoid breaking the normal mipmapping and such. I don't think you'd have to go as far as having half the texture on either side, but it'd be worth experimenting.