I have a copy of "Radiosity, A programmers perspective" sitting on my shelf and can recommend it. IMO it does a good job explaining the fundamentals and concepts that Ian Ashdown himself is quoted in the article to have struggled with initially.
It is one of those books, where the author step-by-step pieces together a program and has the explanations structured around that. In this case, it's a radiosity renderer written in C++ called "Helios". At the time of writing, 32 bit Windows was the hot new shit, so the book takes a few detours explaining Windows API and along the way also develops a tiny software rasterizer for visualization.
Sadly, I no longer have the floppy that came with the book and the website (helios32.com) seems to be defunct. It's indexed in the wayback machine tough. The book appears to have been freely available through website for some time already, but I cannot find a snapshot of the source code.
It is one of those books, where the author step-by-step pieces together a program and has the explanations structured around that. In this case, it's a radiosity renderer written in C++ called "Helios". At the time of writing, 32 bit Windows was the hot new shit, so the book takes a few detours explaining Windows API and along the way also develops a tiny software rasterizer for visualization.
Sadly, I no longer have the floppy that came with the book and the website (helios32.com) seems to be defunct. It's indexed in the wayback machine tough. The book appears to have been freely available through website for some time already, but I cannot find a snapshot of the source code.