A modern, open-source rewrite of the proprietary GameMaker 8 runner.

GameMaker is an IDE for creating Windows games, developed by YoYo Games. GameMaker 8 (GM8) was the last of the numbered releases of GameMaker, released on December 22nd 2009 (surpassing GameMaker 7) and succeeded by GameMaker: Studio in 2011. Due to the huge behavioral differences between "Numbered GameMaker" and GameMaker: Studio, as well as Studio's lack of backward-compatibility, GM8 is still widely used, with thousands of games to its name. One of GameMaker's strengths as a game engine is its ability to compile an entire project into a single executable. No external dependencies or installers, just compile, send the .exe file to your friend and they will be able to play your game. This is achieved by having the target executable act as a phase file for the entire collection of assets required to run the game. In other words, that .exe file contains not only the game engine code, but all of the objects, GML code, sprites, room layouts etc. required for the game logic. This behaviour was made optional in Studio, giving the creator a choice between standalone executable or .msi installer (although it extracts the contents to a temporary folder instead of having the executable contain all the assets), but in GM8 this is the only build option with Windows being the only build target.

The goal of this project is to create a program which will be able to parse GM8 .exe files and play the game contained within. It should mimic the behaviour of GameMaker 8's engine as closely as possible, down to the sub-frame. Strictly speaking, emulator is not a correct term. In computing, an emulator is a piece of software on a computer system which emulates the behaviour of a different computer system. We aren't emulating any computer system, just the GM8 engine. A more accurate term would be sourceport but emulator sounds cooler.

This project has only been worked on by two people so far in their little free time, contributions are very welcome - however we'd encourage getting in touch beforehand.

• Adamcake's absurd amount of runtime research.
• DatZach's decompiler for "documenting" the loading sequence.