Mappend PrimitiveArrays or PrimitiveStreams of varying topologies.

[PiotrJustyna]

First of all, I appreciate your work on the library. I've been playing with it for the last few weeks and I really like it so far.

While experimenting with the library's capabilities, I stumbled across combining PrimitiveArrays (or PrimitiveStreams) of varying topologies, e.g.

• triangles + points
• points + lines
• etc.

I'm playing with rendering (any-topology) objects and their per-vertex normal vectors (represented always as lines) and could really use that feature. Is this something you have ever considered implementing? If not, is it because what I'm after can be achieved with some other mechanism?

Thanks and keep up the great work!

[plredmond]

Since the topologies of PrimitiveArrays and PrimitiveStreams and similar are represented as a type parameter, they're distinct types. As a result, they won't work with the mappend function which requires both of its arguments to be of the same type. This is pretty core to GPipe's design and isn't likely to change.