Give even a cursory review of code for those id Software titles to see that they were not rewrites from scratch (http://fabiensanglard.net/ http://fabiensanglar

Give even a cursory review of code for those id Software titles to see that they were not rewrites from scratch (http://fabiensanglard.net/ http://fabiensanglard.net/ gives a wonderful overview of each.) Even without any revision history from one to the next, the structure of each code base shows a continuity and evolution of thought and design that disproves the theory. As I understand it, towards the end of the development cycle for each game, once the core tech was in solid and in place, John Carmack would branch off to aggressively pursue research and development on next gen graphics and tech, leading to a lot of new and rewritten and expanded code, yes, but still not starting from scratch each time. Historically speaking, his act of open sourcing those codebases and the chronicle of cutting edge graphics/gaming development that they represent is a significant record of and insight into one of our generations leading minds. His work ethic and dedication is pretty phenomenal, he is a big personal inspiration.