I made a slight change to the lighting model today. There are still lots of unknowns concerning how various lighting components interact with the polygon color, and specular lighting is still un-emulated, but I think these most recent changes are along the right track and I wanted to see what everyone else thinks. The attached zip file contains new fragment (F.glsl) and vertex (V.glsl) shaders for curious folks to test out. To use them, extract them to your Supermodel directory and add '-frag-shader=F.glsl -vert-shader=V.glsl' to your command line (or set FragmentShader="F.glsl" and VertexShader="V.glsl" in Supermodel.ini).
For the most part, you won't notice the difference, it's quite subtle. There is a profound effect on the expert course in Daytona 2. I'm afraid it might make the road surface too bright. Can anyone who has recently played the real thing confirm? It does fix the spotlight during the countdown (see attached screen shot) and static shadows on the ground are much more visible. Drive over to the shipyard area and look for the shadows being cast on the track surface there to see what I mean.