Yep - this is exactly what I saw when I had triangulation on. But I think in theory a weighting by arc-angle could fix this. Two of the three triangles at a given vertex will share 90 degrees of "span" and the other will have 90 to itself - by this weighting, normals will go back to vertical. I don't know what the effect would be on other shapes.

BrickSmith currently uses non-indexed primitives, and in that configuration, breaking quads into tris is a net performance loss:
- It increases vertex count.
- We hardware-instance together multiple bricks, so our total draw calls is low - so calling glDrawArraysXXX twice isn't a huge problem. (The mac drivers also do a good job of getting the second draw call out quick if no state has been changed.)

I plan to re-measure this once I have indexing working - the indexer is partly done and it looks like it will cut VBO size in half or better.

cheers
Ben