I suspect that you could be faster & higher quality now by doing GPU ray tracing instead of render-to-textures. The big speed advantage of GPU ray tracing would come from the fact that you can make the rays to sample into your lightmaps for lots of lightmap texels and run them all in one big batch. Quality comes from the fact that you can use all the fancy raytracing techniques for sampling, monte carlo methods, etc. and it's rather easier to do variable-resolution sampling (eg. start with 50 rays per lightmap texel and add more if there's high variance). In fact, you could set up all the rays to sample into your lightmap texels for your whole world, and then run N bounces by justing firing the whole gigantic batch N times. Of course the disadvantage to this is you have to implement your whole renderer twice, once as a raytracer and once for normal rendering, avoiding that is the whole point of using the hemicube render to texture method.
Was talking to Dave and randomly mentioned that I thought the new Rvalue references were retarded because you can basically do everything they give you using RVO and swaps. But then I did some more reading and have changed my mind. Rvalue references are awesome!
Want Speed Pass by Value. � C++Next (Dave Abrahams series on value semantics)
C++ Rvalue References Explained (good intro)
A Brief Introduction to Rvalue References (Howard E. Hinnant, Bjarne Stroustrup, and Bronek Kozicki)
Rvalue References C++0x Features in VC10, Part 2 - Visual C++ Team Blog - Site Home - MSDN Blogs
rvalue reference (the proposal document)
InformIT C++ Reference Guide The rvalue Reference Proposal, Part I
Basically it lets you write templates that know an object is a temporary, so you can mutate it or move from it without making a copy. I think one problem we sometime have as coders is that we think about our existing code and think "bah I don't need that" , but it's only because we have been so conditioned not to write code in that way because we don't have the right tools. C++0x makes it possible to do things in templates that you always wished you could do. That doesn't necessarily mean doing lots more complicated things, it means doing the little things and getting them exactly right. "auto" , "decltype" , "[[base_check]]", etc. all look pretty handy.