This project was originally a mod to enable the in-game radio in Saints Row: Gat out of Hell.
The previous games in the Saints Row series all had in-game radio, and Gat out of Hell does not.
By reverse engineering the relevant parts of the game executable, I discovered that the code to handle the radio was still in the game - it was just forced off.
The first version just forced the radio to be enabled at all times. Later versions re-enabled the toggle for turning the radio on and off - and even the ability to insert whatever tracks you like into the game.
Further feature requests and more reverse engineering of the game executable led to more features being developed:
The mod works by providing a replacement "xinput1_3.dll" file - this file is used by modern PC games to handle input from gamepads. Replacing this file with a different version allows code execution in the same process - and from there it is relatively easy to patch the necessary code in memory.
Source code: SaintsRowRadiopocalypse on GitHub
Downloads and more information: Saints Row Mods