Id has a long history of releasing source to their games. Unlike previous sourcecode releases, this source download includes all of the art and sound assets. This is unusual, but perhaps not too surprising. For the programmer who wants to experiment, getting the art assets out of the commercial release is not possible in the same way that it was on previous Id games. In addition, it doesn’t directly compete with the commercial release since most players will not be registered iPhone developers or posess a jailbroken iPhone.
Now, I’m not posting to promote the application – there is enough press about it. I’m posting to highlight a few things that are interesting to me.
- Like most Id sourcecode releases, John Carmack provides documentation that provides interesting context on the release. The larger document can be read here. And the second smaller document can be read here.
- This was an opportunity for John Carmack to revisit and port code that he had written 16 years previously. We’ve touched on this topic previously in regards to CLIPS.
- Rather than begin with a port from the original source release, Carmack started from an open source project that was derived from his source: Wolf3D Redux.
- It appears that the Wolf3D Redux code is actually a combination of two of Carmack’s previously released codebases, in John’s words: "basically a graft of the Wolf3D code into the middle of a gutted Quake 2 codebase".
We’ll revisit the topic of Id, and the portability of their games in future postings as well.