I need to figure out how to calculate normals for this... and when i look at it in wireframe mode, i get weird effects. Not sure why, maybe it's normal. Here's what wireframe looks like.....
I colored the weird lines. They go from the rightmost vertex to the leftmost vertex on the next row... i'm not sure if that's working as intended or not. I'm using a triangle strip to render the terrain, so I dunno. I'll look into it.
A triangle strip uses 3 consecutive points - so when you wrap the line, it uses the two points from the last triangle (on the left) and the new one on the right.
To fix it, you'd usually make a 'degenerate triangle' - one where two of the points coincide - so, once you finish a row, repeat the last point of the last triangle before starting the next row.
(Actually, i'm surprised it only shows up in wireframe mode - are you doing anything different for that other than just setting the render state to wireframe ?)
Wyzfen