- Bi-directional approaches
- Path spaced approaches
- Read various papers from the companies who are in the field you would like to go into
- Spectral ray-tracing (instead of RGB, look at colour frequencies / wavelengths)
- Glossy BRDF model
I would also like to see if I can make any more optimisations to the code.
Maybe I could also move away from the object-oriented model and not use `new` and `delete` so often, really focus on the data flow.