Update README.md

README.md

@@ -4,6 +4,19 @@
 
 ![Discord Chat Channel](docs/discord-badge.jpg) [Discord Chat Channel](https://discord.gg/f5StsuP)
 
+Dethrace is an attempt to learn how the 1997 driving/mayhem game [Carmageddon](https://en.wikipedia.org/wiki/Carmageddon) works behind the scenes and run it on modern systems.
+
+## Introduction
+In 2014, Watcom debugging symbols for an earlier internal build [were discovered](http://1amstudios.com/2014/12/02/carma1-symbols-dumped) on the [Carmageddon Splat Pack](http://carmageddon.wikia.com/wiki/Carmageddon_Splat_Pack) expansion CD release. The symbols unfortunately did not match any known released executable, meaning they were interesting but not immediately usable to reverse engineer the game.
+
+This is what it looked like from the Watcom debugger - the names of all the methods were present but the code location they were pointing to was junk:
+
+![watcom-debugger](http://1amstudios.com/img/watcom-debugger.jpg)
+
+_CrayzKirk_ from the Carmageddon community then picked it up and did the painstaking work of manually matching up functions and data structures in the DOS executable to the debugging symbols.
+
+After months of work, we are slowly replacing the original assembly code with equivalent C code.
+
 ## Dependencies
 
 ### SDL2
@@ -37,6 +50,18 @@ make build
 
 ## Run tests
 
+A subset of tests do not require `DETHRACE_ROOT_DIR`. They run via Github actions when code is committed to this repo. This allows us to keep nice and clean and avoid storing any potentially legally problematic resouces in our repo.
+
+The majority of tests _do_ require `DETHRACE_ROOT_DIR`. 
+
+To run the full test suite, you must have a copy of the original *Splat Pack* data.
+
+```sh
+export DETHRACE_ROOT_DIR=/path/to/carmageddon_splat_pack
+```
+
+To run 
+
 ```sh
 make test
 ```
@@ -50,3 +75,14 @@ DETHRACE_TEST_ARGS="-n test_name" make test
 ```sh
 make run
 ```
+
+## Credits
+- CrayzKirk (manually matching up functions and data structures in the executable to the debugging symbols)
+- The developer at Stainless Software who left an old debugging .SYM file on the Splat Pack CD ;)
+
+## Legal
+Dethrace is released to the Public Domain. The documentation and function provided by Dethrace may only be utilized with assets provided by ownership of Carmageddon.
+
+The source code in this repository is for non-commerical use only. If you use the source code you may not charge others for access to it or any derivative work thereof.
+
+Dethrace and any of its' maintainers are in no way associated with or endorsed by SCi, Stainless Software or THQ Nordic.