Reverse Engineering Crazy Taxi, Part 2

Summary

In part 1, we covered some basic elements of reverse engineering in order to decode Crazy Taxi’s .all file format, which turned out to be an archive format used to bundle thousands of the game’s asset files. I also stressed a couple lessons I’ve learned while reverse engineering, which I’ll go ahead and recap here: Take detailed notes as you’re reversing. You never know when that random offset you noticed 2 hours ago will come in handy again. As early as possible, test your theories with actual code. Writing a quick script that checks your assumption across hundreds of files will save you tons of time compared to manually scanning, and that code can serve as a testbed for further discovery and theorizing. In this post, we’ll build on these lessons with a couple new techniques in order to puzzle out the .shp file format, which I suspected might have something to do with the game’s 3D models. What’s in a name? But why do I think .shp files have anything to do with models? Well for one, .shp looks a lot like the word “shape”, doesn’t it? Admittedly, this is fairly weak evidence by itself, but it was enough to give me my initial hunch and was luckily bolstered by a number of other observations: Prior to expanding the .all archives, the only .shp file in the game files is called cube0.shp, and cubes are famously a kind of shape. It also seemed roughly the size I’d expect for a cube’s geometry (i.e. small) Besides cube0.shp, all the other .shp files live in archive files with names like polDC0.all, polDC1.all, etc., whose prefix pol kinda suggests the word “polygon” The 2,744 .shp files within those archives have names like CZ_train_B.shp, course_4_129.shp, CZ_IMPALA.shp, which all seem like reasonable names for game models Running with this theory, and assuming cube0.shp indeed contained a cube’s geometry in some Crazy Taxi format, analyzing that file seemed like a great first step to cracking this nut. Rosetta Cube Cubes, as you might know, are pretty simple shapes. Aft...