In high school and college (2005-07), I learned to modify the game Halo PC by talking to reverse-engineers online:
I approached David Skotnicki (TocaEdit) who created a Field of View tool for Halo PC, allowing you to change the angle of the perspective projection used for rendering the game. He taught me the following things as a foundation:
- how to use TSearch and Cheat Engine to analyze the effects of in-game actions on locations in memory
- how to find locations in code which accessed its values
- how to re-route the game to use our custom code