Just curious I was reading http://realtimecollisiondetection.net/blog/?p=86 when I decided to think about actually implementing the system as mention, but I faced a dilema. When sorting by key, which includes depth, what depth is that? The centroid of the renderable based on camera position? How do you deal with overlapping objects which centroids are properly sorted? Isn't that a problem? how are you supposed to handle those kind of issues?
In fact I was thinking how does this handles concave objects that wrap other objects within. My first guess was about splitting object into smaller sub meshes and then form the drawcall on the fly by combining those meshes, but seems quite suboptimal.
Any hints would be greatly appreciated, thanks.