So while I wait for a physics fix-up, I thought I'd take a look at that scary omnipresent todo-list item casting a dark shadow on my thoughts - erm... shadows. As is becoming usual with these game dev things, getting an initial implementation working wasn't nearly as hard as I thought it would be (umm standing on the shoulders of giants & all that). It's just that they're, well, ugly as sin really, with the requisite 'surface acne' and blocky low-res shimmery-ness close up. Using a huge shadow map texture (1024-2048 square!) close to the camera helps somewhat, though I've not done anything too clever with the light view and frustum yet (enter cascade shadow maps or similar).
Also, using glCopyYadder to capture the scene depth buffer was being limited by the app window size, so I've been forced to make the jump to using frame buffer objects too - delving into a rather arcane and temperamental part of OpenGL (boy is DirectX looking (slightly) more attractive nowadays, especially with the Longs Peak debacle. /me remembers back to my first blog comment...)
Getting the shadows integrated (I have to sample the shadow texture in each shader) also revealed errors in the ambient lighting calculations in the terrain and mesh shaders, which was nice.

Anyway, nuff yacking, here's how shadows change the look of the old gfx... (yep: could do with some textures about now I think). I'm now looking at overcoming the various idiosynchrasies as we speak. Ysaneya's journal has been quite helpful here describing his journey through the same territory.