The main thing that didn’t work was trying to draw just the square tiles and nothing else. The failures from that aren’t very exciting, you end up with overlap on one side and a gap on the other as the inner clipmap levels move around.

The funniest bugs I ran in to were all to do with the snapping. If you don’t snap the levels at all it looks like this, at one point I had a bug where I was snapping the texture coordinates but not the actual world position of the mesh so the world would tremble as the camera moved around, and my best bug had the entire terrain flapping up and down like mad. (don’t remember how I did that one sadly)

Also lots of mundane garbage with mesh generation, like random triangles stretching across the whole world and holes in the ground.

Normals are mostly fine across transitions, but if there’s high frequency detail in the terrain there can be quite a big pop.