I'm making a cube. The half of the cube is green, the bottom is gray. It's supposed to be a precise split, but no matter what I do, it looks like this (image is of an edge of the cube):

![problem with textures](https://i.sstatic.net/ZkK3D.png)

One side is above the halfway point, the other side is below the halfway point. If I add a single pixel to the left side, it goes below the halfway point. Similarly, if I add a single pixel to the right side, it goes over the halfway point.

How do I precisely split the cube into green and brown, with the dividing line being exactly halfway between top and bottom?


This question is related: https://blender.stackexchange.com/questions/28952/exported-uv-map-is-blurry-and-doesnt-line-up-with-uv-mappereditor but it has no answers. I suspect I may have a similar problem, or at least I could fix my problem if I knew how to fix that other problem.