I'm in the process of cleaning up my engine code. It has gotten quite messy due to hacking in this or that and now I want to clean all that up.
What is a good namespace for billboards? I've started using my classes to only spit out vertices. Later on then another class can use these classes to create the vertices they need yet they are not tied down to a specific vertex type. So if you need a billboard with 4 textures and a shader you can do that but you will not have to gen the vertices for the billboard and the base vertex data for the billboard is not associated with or tied down to a specific type of vertex buffer.
So what are billboards? They don't really fit into primitives.