It's taken me weeks to get simple Phong lighting model up and running. Bugs tend to be well hidden if you're looking at an object placed at the origin, or the camera never moves, or the light source is pointed along a certain axis, or you're always using sampler 0, or etc. As soon as you start them all moving/changing, well, it doesn't look so hot .
Anyway I think I finally cracked it. Compared to how long it took me to do Phong, adding normal mapping was a breeze. The only trouble was that ASSIMP doesn't bother checking for a map on the bump channel in a .3DS export, so I had to mod it to get it to add a normal map to the material description. It does magically calculate tangent and bi-normals for vertices though, so that's something going for it.
This is a major achievement for a dumbass like me, so I thought I'd share :-)... Obviously I don't have a knowledgable expert sitting next to me, so I'm assuming it's correct just by looking at it myself. I'm wondering if it looks correct to everyone else?