Hacking the Scumm Engine

This is a project to understand the SCUMM (Script Creation Utility for Maniac Mansion) engine for the C64. Once it is understood, I want to carry the project forward and create a SCUMM Editor to run under Windows that will allow users to edit the content and create their own Maniac Mansion style games to run on the C64.

Project History

This project was started by Lloyd Rosen (who runs the 2D Now gaming community) and myself back around August 2002 and then put on hold.

So far we don't have much but it is promising. The basic SCUMM scripting language, which is the same across all platforms (PC, Amiga, C64) has been largely discovered. Here are some sites with information:

  • SCUMM VM - an open source SCUMM engine
  • Mix'n'Mojo - editing tools for the PC versions only
    Below are the documents of what we have found out so far for the C64 SCUMM engine. We also understand the start and end points for room files on the disk. The task right now is to figure out where on the disk it tells the engine where to find the rooms.

    So what can we do so far? We can:

  • manually edit (with a hex editor) the dialog in Zak McKracken
  • manually edit certain parameters we understand, such as where a character walks to on screen. (see scripting language document)
    Note: This sounds good, but if we change the length of the dialog sentences then it throws off the rest of the data. So we are very limited in what we can manually edit right now. This problem will go away when we figure out where the directory information is stored.

    Documents

  • SCUMM Overview (Lloyd Rosen)
  • SCUMM C64 Disk Format (Brian Bagnall)
  • Scripting language
  • Dialog compression

    Note: Please don't write me to encourage me to do work on this. I will do it on my own time when it is available. Only write me if you have found information about SCUMM that I do not have here already.

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