Clipping polygon does not line up with polygon entity

[jjspace]

What happened?

When using the same coordinates to draw a polygon entity and to clip a 3d tileset they don't perfectly line up. The running guess is that there are some approximations in the clipping polygon shader which could account for the differences. @ggetz anything else you can add? This was first reported on the forums

Reproduction steps

1. Load this sandcastle
2. Observe there is a red edge that's outside the clipping area that should've been clipped