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AGI versus SCI – A Comparison

AGI, which Sierra used up until around the release of King’s Quest IV – The Perils of Rosella, was a strictly linear scripting language with a fairly simple bytecode. Much simpler than SCI’s object-oriented virtual machine. But how do they compare?

Inspired by this one particular book that’s ostensibly about SCI but contains only AGI snippets from what I’ve seen, here’s the first playable room in King’s Quest IV, and how it’s initialized. I’ve left out a bunch of stuff for clarity. Because it’s so simple, AGI bytecode is pretty easy to decompile:

if (justEntered)

  if (!nightTime) { v152 = 1; }
  else { v152 = 101; }

  //Place Ego according to the previous room
  if (lastRoom == 1) { position(ego, 141, 82); }
  if (lastRoom == 2) { position(ego, 107, 82); }
  if (lastRoom == 9) { position(ego, 96, 82); }
  if (lastRoom == 10) { position(ego, 80, 82); }
  if ((lastRoom == 11 || lastRoom == 15)) { position(ego, 70, 82); }
  if ((lastRoom == 12 || lastRoom == 14)) { position(ego, 60, 82); }

  //Add some waves in the water.
  set.view(o3, 55);
  set.loop(o3, 4);
  set.priority(o3, 5);
  cycle.time(o3, 3);
  position(o3, 64, 152);


Hmm. Compare that to its SCI equivalent. SCI bytecode is much harder to decompile. You can disassemble it, but until SCI Companion came out it wasn’t possible to decompile it. Still here we are:

(instance Room1 of Room
    picture 1
    north 25
    south 7
    west 31
    east 2
    horizon 100
  (method (init)
    (if gNightTime (= picture 101))
    (super init:)
    (self setRegions: 503 501 504 506)
      isExtra: 1
      view: 665
      loop: 0
      cel: 0
      posn: 203 76
      setPri: 0
      cycleSpeed: 3
    ; Other waves left out for clarity
    (waves add: wave1 wave2 wave3)
    (wave1 setScript: waveActions)

    ; This part is simplified significantly.
    (switch gPreviousRoom
      (south (gEgo posn: 225 188))
      (north (gEgo x: 225 y: (+ horizon 1)))
      (0 (gEgo x: 220 y: 135))
      (east (gEgo x: 318)) ; Y stays the same.
    (gEgo init:)

You might notice that there’s no equivalent to draw.pic and discard.pic and such. The Room class handles that by itself the moment Room1 calls (super init:).

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Musings on iMuse

One of the things I think LucasArts got Sierra beat in with regards to their old point-and-click adventure games has to be the music. I don’t mean that the music itself is better, but the underlying technology.

In SCI, a given music track can have cue points and a loop. These cue points can increase or set a value visible to the game engine, and let the game time things accordingly. Notable examples off the top of my head include the singalong text and images in Freddy Pharkas Frontier Pharmacist, the selection highlight following the beat in Quest For Glory, the singalong in Leisure Suit Larry 6… yeah.

But that’s just one way. The song can nudge the game, and that’s about it. A harmless bit of Mickey Mousing at best.

iMuse, on the other hand? The DirectMusic of its day. Remember DirectMusic? Me neither. Anyway, an iMuse song (near as I understand it) has queued triggers and a sense of beat, allowing the game to say “hey, switch to the cartographer’s version of Woodtick” and the song would wait for the current beat to finish, play a little flourish, and seamlessly transition into a different song. You could cancel them too, if you were fast enough. And let’s not get into the most triumphant example I’ve heard so far, X-Wing/Tie Fighter.

I figure if you give an SCI track beat markers, preload a fill riff, and have a script listen for requests, you might be able to approximate the basics. If you’re playing variations of the same song that only differ in instruments, you might be able to mute specific tracks, or send raw “Program Change” messages if you’re really adventurous…

But yeah. That’s why you can have proper MIDI dumps of SCI games, but you can’t quite hack it with most SCUMM games.

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On snakes

“Watch out! A poisonous snake!”

Who among us who have played King’s Quest V – Absence Makes the Heart Go Yonder doesn’t remember this iconic line?

Thing is, it is of course wrong. The snake is venomous, in that it bites you and you die. Indeed, the narrator gets it right when you look at the snake: “A large, venomous snake blocks Graham’s passage to the east.”

I have nine different versions of this game and only two of them get it somewhat right.

The original diskette version with the separate “walk” and “travel” icons? Poisonous. The CD version? Poisonous, even with some script changes!

The Amiga version? Poisonous.

The v55 and v62 EGA betas? Poisonous.

The French diskette version? Venimeux.

The German diskette version that I acquired while I was composing this post? Ein Giftschlange.

Now, I myself am Dutch, and I can confirm that in Dutch too, something venomous and something poisonous are both giftig. If there was a Dutch version of KQ5, Cedric would likely say this:

(made with Foone’s death generator because it was quicker than modding.)

The Japanese PC-98 version?  毒, doku.

Even though doku means poison, a dokuhebi (properly 毒蛇) is very much a venomous snake.

(Note from December 15: this brings to mind a thing from Orphan Subs’ Stop! Hibari-kun! release about the word wani being both crocodile and alligator.)

Of course, there is one more version left – I only listed eight so far. The ninth is a real slap in the face.

Yes, let’s rewrite the entire game so it can run on the NES and not finally fix this while you have the chance.

So basically English is the only language I’ve seen KQ5 in where there’s separate words for “it bites you, you die” and “you bite it, you die”, and none of the English versions get it right!

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But why did AGI have that big black command line bar to begin with?

Because the original didn’t have popup windows:

By then the picture format and all that was pretty much set or something like that. With SCI, they could do it all from scratch, using their AGI experience as merely a guideline, and images could go up to 320×190.

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Palette Cycling in Space Quest 4

It’s a followup.

Here’s Roger falling through the chronostream in the introduction:

And here’s the EGA release’s take on that shot:

I immediately thought, of course, the EGA release wouldn’t support palette cycling effects. That’s the official EGA release, with an ega320.drvnot the later ones with ega640.drv. Totally different.

But what if I were to make SQ4 VGA use ega640.drv? What would happen? Would the background remain static?

Keeping the answer under the fold for all you epileptic viewers out there.

Continue reading “Palette Cycling in Space Quest 4”

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Palette Cycling in Larry 5

I distinctly recalled just before posting this that one particular room in Leisure Suit Larry 5 – Passionate Patti does Pittsburgh a Little Undercover Work had a palette cycling effect that bit into the 64 global colors of the palette. So I enabled the debug handler, loaded up ScummVM, and Alt-T’d my way over to room 700.

…It looks perfectly right. That’s not right.

Now, you’ll notice the Fast Forward icon isn’t grayed out. That’s what you get when you cheat, but that’s hardly relevant here.

Had I remembered wrong? Was this the wrong screen? No, surely my memory isn’t that bad? Besides, old adventure games are relevant to my interests. I don’t tend to forget things about those.

But then again, this is ScummVM. What does DOSBox have to say?

Thank you, DOSBox. I figure it must be because ScummVM draws it all in truecolor mode, manually applying the effect to the background, as opposed to the original actually changing the VGA color palette.

(Any political implications are entirely in the reader’s head.)

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Adventure game background art

Ah, Sierra. You gotta love the beautiful background art in their VGA games. From the cartoony…

…to the outright pretty…

…you have to admit someone was credit to team.

But then there’s games where they seemingly dropped the ball (in my opinion) for whatever style-related reason…

…or simply didn’t do much “background art” at all…

And that makes me feel…

Well, okay, I guess, about using edited Gmod screenshots from Letrune in “The Dating Pool”, turning this…

…into this:

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