Debug mode in SCI32 games

[kelmer]

This is not exactly SCI programming related but... sort of.

I've heard of a debug mode in some sci32 sierra games (LSL7 and torin's passage to be exact). Something like creating a blank file named classes or something. Is there any truth in this? If it's so, how exactly can one get access to it?

Thanks!

[Brian Provinciano]

This is not exactly SCI programming related but... sort of.

I've heard of a debug mode in some sci32 sierra games (LSL7 and torin's passage to be exact). Something like creating a blank file named classes or something. Is there any truth in this? If it's so, how exactly can one get access to it?

Thanks!

This is true. I heard about it an tried it a long time ago. It worked, but I don't remember how to do it. I'll try the classes thing, sounds farmilliar. I just need to install LSL7 first.

[lskovlun]

The classes thing is correct - however, since it is implemented in
script code, it doesn't work on all games - only those that
include the debug script (which, granted, are most of them).
LSL7 works.

[OmerMor]

It works in SQ6 & SQ6DEMO too.
It has an extensive debug, similiar to the one found in QFG2. you can even edit the room's path polygon, and save it to file in SCI1 language!
All you need to do is create an empty file named CLASSES in the game's directory, and then when the games starts it asks you where you want to start the game (you choose a room from a list).
In the game you can press anytime the '?' key and get the debug menu.

There is also a debug mode in PQ3 I once read about.
What you need to do there is delete/rename the "version" file, and then when the game starts it asks you on which day you want to start, and some other questions. However, I didn't find any debug menu .

One more thing:
In QFG2 you can get the "regular" debug menu (the one you get when pressing shift-shift-minus) if you switch the interpreter file (scidhuv.exe or something like that) with the one found in sierra's christmas card from 1990 - the 16 colors version.

I hope someone will make a detailed file someday that will have all the known debug modes in sierra games... I don't want this knowledge to be forgotten...

[o]

I just found out that there is a way to enable the debug mode in Laura Bow 2:
You'll need special debug script files that somehow found their ways to the internet. They can be found at:
http://www.sierraplanet.com/laurabow2/goodies.html near the bottom of the page.
Very extensive debug mode!

[lskovlun]

Try this one...

In GK2, enable the debug mode by creating the classes file,
then start the game. When the "where to" dialog box appears
enter 98 in the input field.

[OmerMor]

Found a new one:
In Police Quest 4, if you rename the file "PATCHES\4.SCR" to something else, the debug mode is enabled, and you can choose where and when to start, and can access the debug menu by pressing the '?' key.
Since you remove a script, and not add one I guess this script only DISABLES the debug mode, so maybe a similar "disabling script" exists in other games.
Can anyone disassemble that script (it's quite short) and shed some light on this?
I can send that file to people who don't have it and wish to investigate on this.
  Omer Mor.

[Brian Provinciano]

There's definately no disabling script in SCI1 games. Not only does the debug mode not work with my single script test games, but through disassembling of the actual SCIDHUV.EXE, I have discovered that it was completely removed.

I have found a very very early VGA interpreter that has a debug mode, but it is incompatible with all other VGA games. And also, though it's named version "X.XXX.YYY" or something, I've found other interpreters to also be named "X.XXX.YYY" which are completely different, so it can't be clearly identified. I plan on inspecting it further, but at the moment am busy with other SCI stuff.

The PQ4 off my collection CD had a level select in it as well. I think I forgot to copy all the files when I copied it to my HD. I didn't realize it at the time, but thought it was odd.

Thanks for posting the info!

[OmerMor]

Brian,
I think we're not fully understanding each other.
From what I've seen so far, I believe that there are 2 kinds of debuggers in SCI games:

1. The built-in debugger. This one was run when you pressed the "Shift-Shift-Minus" combination,  and is a low-level debugger. This debugger was built in the interpreter file,  and was removed in SCI1 games (I too have one SCI1 interpreter with debugger. I think it's from "Jones in the Fast Lane").

2. A script-debugger (I think AGI games had script-debuggers too). Some of those debuggers were activated upon writing a specific sentence (e.g. "Suck Blue Frog", QFG2). Some were activated upon putting an empty CLASSES file in the game's directory. What they have in common is that they are game-specific, and they're found in the game's script files. I believe they were removed/deactivated for some games.

The debugger I mentioned in PQ4 is a script debugger, and the interesting point is that it was deactivated using another script file: "4.SCR". If you remove that file, the debugger is active again! So if someone could disassemble that script file, we'll:
1. understand this "deactivation" mechanism more, and-
2. might find such scripts in other sierra games.

P.S.
I've written this before, but it's appropriate here too:
There are some files on the net that activates the script-debugger in the Laura Bow 2. This files, when put in the game's directory enables the debugger. I think disassembling those files might be educational as well.

I am willing to send all the files that I mentioned to anyone interested. Just mail me: sitrajunk *at* hotmail.com .

[Brian Provinciano]

I understand you.

All SCI games had script debuggers, and some had internal ones. However, I have been unable to find any SCI0 games that aren't stripped of their script debugger. The SCI0 script debugger showed info on actors and such (as seen on the menubar in some of sierra's screen shots in a promotional video). It was controlled by a global variable, but since the scripts were removed, it won't work. Setting the global variable would just cause a "script.xxx not found" error. I believe it was game.sc which checked this variable to call the script, though I removed the calls from the template during the cleanup.

The internal debuggers are basically about tracing opcodes, viewing/changing memory/objects.

The script debuggers are actually more useful for the game developers. They include info on aspects of the game relating to the class system.

I highly doubt any SCI0 games (excuding the SCI01 QFG2) were released with their script debuggers, just like no SCI0 interpreters have their symbols left in. I'd probably have to write one myself.

If you ever find any SCI0 games with script debuggers, or more importantly, symbols in the interpreter, please let me know which ones they are.

[OmerMor]

There is of course QFG1 with a script debugger - you run it with this sentence: "razzle dazzle root beer".
I'm not sure this is THE script debugger that was controlled using the global variable, so you'll need to check this one further.
About the symbols: I think I have all SCI0 games known, so give me a good and quick way to find out whether the symbols were left in the game, and I'll run a check for you. Can I use an hex editor for that?

P.S.
What about the 4.SCR file from PQ4? Is there anyone willing to disassemble / decompile it? Anyone?

[OmerMor]

Since there seem to be no interest in decompiling the 4.SCR from PQ4 (which deactivates the debug mode), I might give it a shot myself.

Does anyone know how to do the following:
1. Extract resource from an SCI11 / SCI32 (I'm not sure which one is PQ4).
2. Disassemble scripts from SCI11 / SCI32.

  Omer Mor.

[HWM]

Uh... The Police Quest 3 debug mode is activated by setting the attribute on the file "version" read-only...

[HWM]

Also, to be on-topic, my version of Police Quest 4 doesn't have a 4.SCR... It's the disk version, version number 1.000...

[Brian Provinciano]

I've just finished the 25th script of my VGA template, and have five or so left. I normally would look into disassembling it the PQ4 script, but after the 30 EGA scripts, and now 25 VGA scripts, my head is spinning, heh. I'm going to finish disassembling the last VGA scripts then move on to the SCI Studio VGA program itself. After my brain has relaxed from disassembling, I'll dwell into it.

By the way, don't worry! This topic to totally SCI related! Feel free to continue posting to this, and any more topics like it you wish. This message board is open to absolutely anything SCI!