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How to SCI – Old vs New

To make an SCI game today, you can just grab a copy of SCI Studio 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.

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Ball Road

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.

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Police Quest’s flashing siren lights

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.

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