(Originally written 2017-10-07)

To most children of the nineties, “adventure game” was synonymous with “Sierra” and “LucasArts”. When you look at Sierra games like the King’s Quest, Space Quest, Police Quest, and Leisure Suit Larry series, you notice they’re all alike in one particular aspect beyond mere presentation, beyond the fact that they all control the same way: they are all third-person point-and-click adventure games.

Now that’s simplifying a little, since the earliest entries in those series weren’t point-and-click but instead had a text parser. But that doesn’t matter here, not very much.

We have our background image, our animated main character (henceforth referred to as Ego, in keeping with the script code), other animated characters where called for, a mouse cursor, and the status line. In many Sierra games from King’s Quest 5 on the status line is blank. In earlier games it was not, often displaying the game name and player’s score.

Regardless, we can control Ego in a particular way, and by placing the mouse cursor on the status line, we can summon an icon bar:

Click a verb on the left half, then click somewhere in the game screen to act accordingly. Simple. The other three icons open your inventory, allow you to change settings and save/restore, and explain the other buttons. Almost all point-and-click Sierra games work like this.

The important question is, how much of all this is part of the engine, and how much is part of the game? Let’s find out!

As it turns out, the only common aspects that are part of the engine are:

• The ability to draw backgrounds.
• The ability to draw animated elements on those backgrounds, while also letting parts of it obscure them.
• The ability to play sound effects and music on a variety of sound hardware of the time.
• The ability to draw text.
• Mouse, keyboard, and joystick input.
• The ability to save and restore the game state.
• A simple graphical user interface — windows, buttons, text fields and such.
• The ability to overrule the way windows look, to change their border style in script.
• The ability to draw a status line.
• The ability to tell how to go from one point to another, in various ways.
• For the later games, the ability to do various color tricks.
• For the old SCI0 games, the ability to use a pull-down menu bar.
• For the old SCI0 games, the ability to try and transform an English sentence into recognizable keywords.

That leaves this plethora as purely scripted:

• What an animated character is.
• What Ego is and what they can do that other animated characters can’t.
• What an inventory item is.
• How to respond to a click.
• What the icon bar is, and what buttons are on it.
• What a room is.
• What literally anything being an abstract “object” is. This covers a lot of ground.
• For the old SCI0 games, what goes into the menu bar and how to react to its use.
• For the old SCI0 games, how to invoke the text parser, and how to respond to its results.

The game code can’t tell if you’re using the 320×200 256-color VGA driver or the 640×480 dithered EGA driver, only the abstract “how many colors do we have”, or “how many voices can we play at once” instead of knowing that we specifically use the PC Speaker for music output, or the Roland MT-32.

Those games I listed at the start are all third-person point-and-click adventure games because they all share a common set of scripts that define what an adventure game is. As such, not all Sierra SCI games are adventure games:

One is a board game, the other a series of puzzles. Dr. Brain shares the user interface scripts common to the rest of them, but Jones is nothing alike. And yet, all of them are the same game engine. The script code is in the same format throughout, as are the audiovisual elements. System calls for the script code to use are the same, all throughout.

Sierra’s Creative Interpreter is not a third-person point-and-click adventure game engine, is what I’m saying.

You could remake Myst in it, after all. If you wanted.

Did Sierra ever call the various versions of SCI the same names we use? We being the fans, the tool creators, and the ScummVM developers?

It’s unlikely.

One thing to keep in mind is that the interpreter was in near-constant development by one team, while other teams made the games. Every so often the game developers would pull in the latest interpreter and system scripts from a network share. Another thing to keep in mind is that the version numbers are a little weird in places, and that the games themselves had their own version numbers on top of that, so for example you could have King’s Quest 4 version 1.000.106 running on SCI 0.000.274, but also KQ4 1.000.111 on the same interpreter, released five days later, and the later update with the changed graphics that was version 1.006.003 running on SCI 0.000.502.

The first generation of SCI, the one we call “SCI0”, had versions starting with “0.000”, such as the KQ4 example above. This covers every single 16-color, parser-based, English-only game, with the lone exception of the Police Quest 2 PC-98 release. That was version “x.yyy.zzz”, no joke. This generation can also be subdivided into two blocks, where versions up to 0.000.343 had green button controls instead of using whatever the window color was set to, covering the ’88 versions of KQ4 and the first version of LSL2, and the rest covered all the other games.

What we call SCI01 had versions starting with “S.old”. At least “x.yyy.zzz” has the placeholder excuse but whatever. SCI01 games were just like SCI0 on the surface, but had support for multiple languages (previously introduced in version x.yyy.zzz), and saw no more releases than ’88 SCI0 — six of ’em. So technically there’s nothing about that version string to inspire “SCI01”, besides perhaps KQ1 using “S.old.010″ 🤔

Next up was SCI1, which came in both EGA and VGA and usually had versions starting with “1.000″. There is one game, Quest for Glory 2, with five different interpreter versions that still had the text parser (and technically one Christmas card) before it was removed in favor of the icon bar. Some SCI1 games again have interpreters with very strange versions — it appears Eco Quest and Space Quest 4, among others, had some Special Needs™, given interpreter version “1.ECO.013” and “1.SQ4.057″. But on the whole you could still tell from the first character in the version that these were SCI1 interpreters.

SCI11 removed the multi-language support in favor of things like scaling sprites and the Message resource type. All SCI11 interpreters in the wild use versions starting with”1.001“, except for the ones used in Laura Bow 2 (“2.000.274”), Quest for Glory 3 (“L.rry.083”), and Freddy Pharkas (“l.cfs.081”), among a straggler or three.

Up to now these were 16-bit real-mode applications. SCI2, with versions starting “2.000” was a 32-bit protected mode application instead, with the ability to use much more memory and run in a SuperVGA video mode. No SCI2 interpreter found in the wild seems to stray from this version pattern, mostly because all SCI2 games use version 2.000.000. SCI21, in turn, runs on interpreter version 2.100.002, although there are technically three different sub-versions of 2.100.002. That’s not confusing at all. And finally, SCI3 was only seen in interpreter version 3.000.000.

I’m thinking after the switch to 32-bits, they must’ve stopped automatically bumping version numbers on build.

So what does Sierra call them, then? Well, sources say that Sierra called the 32-bit interpreters SCI32, and the source code archive that I based SCI11+ on was SCI16.ZIP. But none of the changelogs and such seem to refer to SCI0, SCI1, or whatever.

 

 

Happy slightly belated new year 🥂

Oddly, this one’s entirely script based.

I was reminded of this when I watched one of Space Quest Historian’s videos, where he played the Space Quest 2 remake by Infamous Quests. Now, one thing he mentions about the version he plays in that video is that besides the narrator being muted so he can narrate it himself, well…

but recently Steve Alexander, who was one of the co-CEOs of Infamous Quests had a little peek around the old game files and decided to spruce it up a bit, fix some old bugs, add some you know, touch-ups here and there. Most importantly, at least according to him, replace the standard AGS font with something that looks a little more Sierra-ish. And that’s the version I’m going to play.

All well and good but then the main menu appeared and I noticed just how important this font thing seemed to be.

One thing immediately came to mind when I saw this. Notice how the button cuts into the caption? If I was a betting cat, I’d say the original version’s main font was just slightly shorter than this replacement. Also when I prepared the image I noticed each of these buttons has a different height, but that’s not the issue here — that’s just sloppy work.

This thing with the buttons cutting into the message text? It can’t happen accidentally in SCI0/1, but it can easily happen in SCI11. How is that?

In SCI1, the system scripts include a PrintD function. It’s pretty powerful on the face of it:

(PrintD
	"Would you like to skip\nthe introduction or\nwatch the whole thing?"
	#at 100 60
	#new
	#button "Skip it" 0
	#new
	#button "Watch it" 1
	#new
	#button "Restore a Game" 2
)

And that gives you this:

The function itself will track how large every item should be as they are defined, and adjust the final size of the window accordingly. Just to simplify the explanation a bit. And then it’ll return the value of a given button so the game knows how to react.

(Update: SCI0 had Print which worked not entirely unlike this, and SCI1 added PrintD as a more streamlined variant with #new support, because…)

In SCI11, Print is now an object. You have to call a bunch of methods on it, in sequence, then finish with an init: call, and that will trigger its display and return the value chosen. But one important distinction is that addText:, addButton:, and its ilk… don’t automatically position themselves. You have to do that yourself.

That’s why these games came with a built-in dialog creation tool, among others. It’d create code like this:

; DialogEditor v1.0
; by Brian K. Hughes
(Print
	posn:		0 28,
	font:		0,
	addText:	{bluh bluh} 71 18,
	addButton:	0 {button} 71 30,
	addButton:	1 {button} 0 0,
	init:
)

The Sierra programmers could then integrate that into their game scripts. But importantly, those manually-positioned buttons could overlap other controls.

(Update: … PrintD also had a dialog editor made for it. This is pretty explicitly stated in the changelogs.)

AGS dialog boxes also use manual positioning, just with a nice WYSIWYG form editor. So if you take a perfectly good (yeah right) introduction menu and change the font for one with a higher X-height and don’t adjust things… you get that SQ2 window.

Update just because: this is what the SQ4 intro menu would look like with font.001 instead. That is, with SCI1’s PrintD and its automatic layout.

To make an SCI game today, you can just grab a copy of SCI Companion and use that to import graphics and music, do the scripting, text… basically everything but drawing bitmap-based backgrounds. You get a copy of the interpreter matching the template you chose, the system scripts are all set up for you, and you can just hit Compile, watch it work, and it’ll even automatically run the game for you in DOSBox, perhaps even starting you off in a specific room.

But dear lord do we have it easy nowadays.

In the old days, making an SCI game involved several separate utilities, many of them interface-less command line tools, and a particular network setup. That is, the tools expect to be invoked from a specific hard drive letter, as they are provided from one point of the network. There’s another where the system programmers keep the latest builds of the interpreter and system scripts, and the team for a given game has a batch script file to pull the latest into that game’s working directory. Writing the actual script code is roughly the same as it is now, but instead of a dedicated script editor they mostly used Brief. To test their changes, the programmers had to invoke SC, the Script Compiler. Given that Brief was apparently pretty extensible, this could probably be done from there.

While we mostly work directly on RESOURCE.### files, Sierra’s games were developed what I call loose-leaf style. Each type of resource was stored in its own folder, and a “wherefile” specified where each of them could be found — they were basically just RESOURCE.CFG by another name, really. And that name was literally WHERE. Turns out you can specify which configuration file you want the interpreter to use.

view=../view
sound=../sound
pic=../pic
font=../system
cursor=../system
videoDrv=/system/ega320.drv
soundDrv=/system/std.drv
kbdDrv=/system/ibmkbd.drv
joydrv=/system/joystick.drv

To make the game, they didn’t use makefiles. They used batch scripts that invoked SC and compiled the .sc source files to .scr files in the SCRIPT directory, and copied over the script resources from SYSTEM.

Given how relative paths work, running another particular batch file would run the interpreter from one directory while in another, from which point the paths given above can be considered valid. Since they didn’t have the “start at the room specified in this file” feature that SCI Companion’s template game adds, we get the game-specific debug modes that ask for a room number on startup, as extensively documented elsewhere.

And then, when the game is considered fit to ship, they build a list of which resources go on which disk, pass that to yet another command-line tool, which goes through all that and produces the RESOURCE.### files. Copy the result and there you go.

That list does not need to include all resources though. Indeed, as there are things that are included in the game data but left unused, there are some things that never got on a release disk in the first place. Let’s just say some things in the Larry source assets are even raunchier than you’d expect.

The dictionary for AGI and SCI games’ text parser input is stored in alphabetical order. This allows a prefix-based compression:

• another
• any
• appear
• appearance
• apple
• at
• attack

Though the formats for the two engines’ dictionaries are completely different, they share this one aspect. Each of these words is then assigned a group number which is then used to store the said specs. I’ve written about that before. The thing is that when you decompile a game script, you can’t tell which synonym from a given group was originally used. And that’s why when you decompile Leisure Suit Larry 2 and look in the scripts regarding really any female character you’ll see them being called bimbos.

(if (or (Said 'call/bimbo,agent') (Said 'get,buy/ticket'))

That is of course because “bimbo” is in the same group (#42) as “woman” and “lady”, but alphabetically comes before them. “Agent” is in its own group (#50) together with various other jobs. You can call this particular woman either by gender or by profession. You can even call her a KGB agent and the game will allow it. By that same token, “call” is in the same group as the “talk” you’d expect to see here (#11).

But the decompiler has little to no idea of these things.

I have recently acquired the full source code for Larry 2, and that shows a slightly different, more sensible word choice:

(if (or (Said 'talk/girl, clerk') (Said 'get, buy/ticket'))

That is of course because these are the actual word groups being used here:

11	42	50
talk speak converse call	woman girl lady stewardess blond chick blonde slut broad bimbo maid receptionist secretary mother mama momma mom	clerk waiter waitress bartender storekeeper shopkeeper agent kgb kgbishna custom attendant shark

You can see how alphabetical order would mess that up.

And by that same token I can now securely say that the debug cheat code in Larry 3 is not in fact “ascot backdrop”.

“Backdrop” in Larry 3 is in group #1063 together with “put”, “drop”, “release”, “set”, “stash”, and various other “put something here” verbs. You know by now how the smart fella who discovered the debug cheat may have gone about it, and how “backdrop” would be the first word in that group. The canonical phrase however, is

Ascot Place

Because of course if I have the Larry 2 code why wouldn’t I have Larry 3 as well?

(cond
  ((Said 'ascot/place')
    (^= debugging TRUE)
    (if debugging
      (Print "Hi, Al!")
    else
      (Print "\"Goodbye.\"")
    )
  )

The question is… why is this the debug phrase?

And the answer? It’s a callback to Larry 2:

And just like that this post’s title makes a little sense.

The flashing siren lights in the title screens for Police Quest 1 and 3 are sort of interesting, because they are not quite a simple matter of calling (Palette palANIMATE) once or twice. In fact it’s called eight times each frame! Here’s the final result:

And here’s the Script at the heart of it:

(instance cycleColors of Script
  (method (changeState newState)
    ; Fun fact: the switch isn't actually needed.
    ; Not in this use-case.
    (switch (= state newState)
      (0
        (Palette palANIMATE 208 213  1) ;blue in the middle
        (Palette palANIMATE 213 218  1)
        (Palette palANIMATE 218 223  1)
        (Palette palANIMATE 223 228  1) ;blue on the side
        ; Note that we're switching from 1 to -1 now.
        (Palette palANIMATE 229 234 -1) ;red in the middle
        (Palette palANIMATE 234 239 -1)
        (Palette palANIMATE 239 244 -1)
        (Palette palANIMATE 244 249 -1) ;red on the side
 
        ; Almost immediately do it all over again
        (= cycles 10000)
        (= state -1)
      )
    )
  )
)

The palette here has a very particular setup. The lowest colors, #208 to #249, are set up like this:

Each of the eight siren colors in the image has its own four-step palette, individually rotated! It looks kinda like this:

If that one black entry wasn’t in the way between blue and red, it’d line up better, but what can you do?

What’s particularly funny about this is of course that no SCI interpreter with fewer than 256 colors implements this feature.

The cycleColors script is still there and is still invoked. Just like with the chronostream animation in Space Quest 4.