I’m going to try and update more often and not just use this blog for software updates. That reminds me, I think Scummbler is broken for SCUMM V4 scripts – I really need to upload a fixed version some time.

Scummbler v2 r11 now returns error codes when the program exits. It also fixes an issue with the “cursorCommand” instruction not being parsed at all.

Here are the error codes:

• 0 =no problems
• 1 = error in the arguments passed into Scummbler
• 2 = known error parsing the script(s)
• 3 = unknown error parsing the script(s)

Source/Python Script

http://www.jestarjokin.net/sw/scummbler_src_20091028.zip

Win32 Binaries

http://www.jestarjokin.net/sw/scummbler_bin_20091028.zip ]]> http://www.jestarjokin.net/blog/2009/10/scummbler-v2-r11/feed/ 0 http://www.jestarjokin.net/blog/2009/10/scummbler-v2-r9/ http://www.jestarjokin.net/blog/2009/10/scummbler-v2-r9/#comments Wed, 07 Oct 2009 10:41:29 +0000 jestar_jokin http://www.jestarjokin.net/blog/?p=33 Scummbler v2 r9 adds the new command line option “-o”, allowing you to specify a file name for the output script. Note that if you specify an output file name, you cannot specify multiple input files (or a directory containing multiple input files). Useful if you want to integrate Scummbler into another application or automated process.

Source/Python Script

http://www.jestarjokin.net/sw/scummbler_src_20091007.zip

Win32 Binaries

http://www.jestarjokin.net/sw/scummbler_bin_20091007.zip

• Fix issue with nested “if” blocks; scripts now compile considerably faster. The exact improvement will depend on the complexity of the script, but as an example, one script that used to compile in 18 seconds now compiles in 4; another script that used to compile in 8 seconds now compiles in 1.
• Fix issue with “duplicate label name” error throwing a different error.
• The Win32 Binaries now include the verb_helper tool.
• Source code package includes the py2exe distutils script.

Source/Python Script
http://www.jestarjokin.net/sw/scummbler_src_20090922.zip

Win32 Binaries
http://www.jestarjokin.net/sw/scummbler_bin_20090922.zip

Scummbler
http://www.jestarjokin.net/sw/scummbler_bin_20090921.zip

ScummPacker
http://www.jestarjokin.net/sw/scummpacker_bin_20090921.zip

ScummSpeaks
http://www.jestarjokin.net/sw/scummspeaks_bin_20090921.zip

SCUMM Image Encoder (mi2img)
http://www.jestarjokin.net/sw/mi2img_bin_20090921.zip

Anyway, new version of Scummbler that actually works is mysteriously available on the main page.

EDIT: Fixed a few more problems with a couple of instructions in r7.

http://www.jestarjokin.net/sw/scummbler_src_20090725.zip

A scene from the introduction sequence of The Adventures of Robin Hood

Robin Hood could be considered one of the first world sims, populated by independent characters, one of which you have some control over (Robin Hood, of course). The gameplay is entirely non-linear, with multiple paths to completion.

I am investigating how to write a modern engine or interpreter for Robin Hood and its successor, Rome: Pathway to Power (aka Rome: AD92), with a path to creating new adventures.

Robin Hood is based on a rules engine/interpreter called Microcosm, which Steve Grand originally created for some educational titles many years earlier. I asked Steve on his blog if he had any source code available, and unfortunately it seemed unlikely, but he did describe Microcosm’s non-linear behaviour as follows:

… in Microcosm that simply translates into producing a DATABASE of IF/THEN statements, instead of the tree structure that would occur in normal code (normal code looks like: “IF A THEN (IF B THEN (…)) ELSE IF C…” – lots of brackets, creating a tree). So a Microcosm rulebase is a long list of completely independent IF/THEN statements, ALL of which are tested every tick of the system clock. Say one of the rules is “If A and B and C and D are true, then do E and F and G”. And say that doing G changes the external or internal environment of a character in some way. Now a different rule (which could be anywhere in the rulebase) might get triggered next tick. It doesn’t matter how the game got to that point.

Interesting stuff! It would probably be a lot easier to write it from scratch, but since we’re trying to support the existing games it’s going to tricky.

Well, I’ve made a start at reverse engineering Robin Hood, starting with something a bit simpler. I’ve written a small decoder for the .VGA and .GFX files, which contain sprites and font characters. These files use a simple variation of Run Length Encoding (RLE). The image to the left shows the first five frames contained within MEN.VGA.

There are some quirks, of course. Some of the image data is hardcoded in the game’s executeable, such as a “default” palette, and the expected file sizes for each image. Most .GFX files store the image’s palette at the start of the file, except for CUBES0.GFX to CUBES3.GFX, which use the default palette. All .VGA files use the default palette.

The compressed images do not seem to contain all the pixels in the uncompressed image; all backgrounds come up one pixel short, and the sprite sheets are missing a few more pixels. I have assumed that the game just fills in missing pixels with 0×00, which seems to match the observed output (check the first screenshot – the very bottom right pixel is black, when the surrounding pixels are dark green).

Here’s some boring information about the image files:

• MEN.VGA and MEN2.VGA are 16 pixels wide, 3840 pixels tall. These files contain the character sprites.
• IDEOGRAM.VGA is 16 pixels wide, 1600 pixels tall. This contains the action icons and UI elements.
• ISOCHARS.VGA is 4 pixels wide, 1024 pixels tall. This contains the font used for in-game dialogue.
• CUBES0.GFX to CUBES3.GFX are all 32 pixels wide, 1920 pixels tall, and contain the isometric tiles (cubes) for each season in the game.
• All other .GFX files are 320×240, and are background images.

Here is my simple decoder script. It works for all Robin Hood images, and from a quick test it can decode at least the backgrounds from Rome. I have included the hardcoded “default” palette, in both VGA and RGB formats.

Robin Hood Image Decoder (Python Script) (2009-07-22)

Next task… RULES.PRG!

Hi! I’m jestar jokin. You might remember from such films as “OH GOD MY BRAIN IS ON FIRE PLEASE TURN IT OFF I’M NOT KIDDING THIS MOVIE IS SO BAD I CAN FEEL MY HIGHER COGNITIVE FUNCTIONS TURNING INTO A GOOEY PUDDLE OF SYNAPSES”, and “Harry Potter and the Rather Hard Maths Assignment (It’s, Uh, A Magical Maths Assignment)”. Please enjoy reading about the fantastic deeds I do instead of going out and getting some sun. Sorry, let me rephrase that: don’t go out and get some sun, read about my fantastic deeds instead!

I’ll use this blog instead of the ridiculous hardcoded text on the main page for news updates, so for future reference, here are all the old news items:

4^th July 2009:
A new version of Scummbler has emerged! It now supports SCUMM V3 and V4, all script types, and other nice things. It could use more testing, so let me know if you encounter any problems. I kind of lost track of development (I put off updating the manual for ages), but it should also support Indy 3 for FM Towns, but not Zak 256.
Incidentally, DOSBox 0.73 is out, but uses a new DRO format, and DRO Trimmer does not work with the new files.

12^th May 2009:
Finally updated mi2img, it actually has command line options now. And that’s it. I have been working on Scummbler to support V3 and V4 scripts, I’m nearly done, I just have to add Indy3’s strangeness, and possibly Zak256. I also have an idea for another SCUMM app…

26^th April 2009:
Here comes V2 of Scummbler! This one is actually pretty decent! It can parse V5 scripts output from ScummVM’s descumm tool, making modifying SCUMM games this easy:
1) Extract the game with ScummPacker
2) Decode appropriate script with descumm
3) Modify text script with your favourite editor
4) Encode the text script to bytecode with Scummbler
5) Replace the original script file
6) Repack the game with ScummPacker
Once again, this only works for SCUMM V5. Hopefully I can work out a graceful way to handle V3 and V4 as well for the next release.
There is also a new version of ScummSpeaks, which adds the ability to do a mass import/export of sounds, and automatically link them to the appropriate lines of text!

26^th December 2008:
Redesigned this page a bit. Also, there’s new versions of ScummPacker, ScummSpeaks, and DRO Trimmer for your pleasure!

9^th January 2008:
Chucked up the Python files for some SCUMM tools. No binaries. Haven’t tested the code to see if it still works, and I haven’t worked on most of it for a long time (since late 2004 to early 2006). Also, I think they’re all hardcoded for use with Monkey Island 2. You’ll need to poke around in the code to get it to work with other games.

These are not user friendly, and barely working. You will need to know something about Python, and probably the inner workings of SCUMM, in order to use them. Thankfully there are a few documents out there about SCUMM (check out the ScummVM site).

28^th September 2007:
Ahoy! While I consider making a dynamic page of some sort, here’s a sampling of some of my brilliant works (and let’s face it, they are fairly brilliant; 9 out of 10 housewives can’t tell the difference between my code and the Sistine Chapel). Well, to be honest, it’s all stuff my computer made, I just put my name to it.