Challenges with MeshWriteData

I am trying to use generateVisualContent delegate to create a procedural line mesh, and I am having some issues. So imagine a vertical line segment from A (bottom) to B(top). I want to draw a line from start to end with a width value. So say w = 5 * Vector2.right.

So my vertices for a given segment should be:
0: A.position + w
1: A.position - w
2: B.position - w
3: B.position - w
4: B.position + w
5. A.position + w

Right?

I set these vertices with the SetAllVertices method, followed by a series of SetNextIndex calls from 0 to 5. Then nothing appears on screen. Interestingly when I set the indices in reverse order, from 5 to 0, I get something.



Half my mesh is now visible, but I can't figure out why the other half (the second triangle) is not appearing at all. I tried changing the order of the vertices and I think I tried pretty much every combination, but still no luck. I feel like I'm doing some dumb mistake and it's driving me crazy. HALP!

 

Oh nevermind, I'm an idiot. I had the wrong z depth on the last vertex.