mesh design issues

Hello all,

A couple friends and I are designing a rendering engine and we ran into a problem. The issue is this. When you are rendering meshes with different effects on them, how do you generalize the rendering? When we looked at it, it seemed like the best solution was a base class DrawableMesh, with various subclasses that do different things, such as a BumpMapMesh, a LightMappedMesh, etc. Each one of these subclasses would know how to set up the rendering for themselves based upon how many textures were allowed per pass on that card, and the various caps of the card. These meshes would have their verteces, textures, and shaders abstracted through a manager that handles reference counting for those objects, and that sort of thing.

The main issue we were having is the huge amount of subclasses required. I mean, to us it seemed you would wind up with a class for every permutation(combination?) of effect. e.g. you could conceivably(don't know *why*, per se) wind up with a LightMappedBumpMappedSpecularMappedSkinnedMesh, and that would have to reimplement the aspect of light mapping, bump mapping, specular mappng, and skinning. This seemed...wrong..to us. Does anyone have any better ideas?

This does seem a bit general for this list, so I'm ccing the GD-design and GD-general lists..please reply there if you feel it more appropriate.

Apologies for a duplicate if any...i sent it from the wrong accoutn at first and the list servers didn't like that.

Any help greatly appreciated.

Dan