Re: [GD-Design] Scripting Engine and C++ Games

[Mickael P. <mpo...@ed...>]

> Yes, you've hit on a big part of the reason for ICE. We wanted a
> language that end users could use. But we also wanted a language that
> could support a robust, object-oriented coding style, because we
> expected to write huge portions of our game in it. We shipped 40K
> lines of ICE code as part of the game.
>
> I do think you should think seriously about your programming language
> design. You can design for simplicity, but just make sure it's the
> right kind of simplicity. All too often, simplicity of implementation
> is confused with simplicity of language design. There are a lot of bad
> scripting languages around that were easy to write but are not so easy
> to use.

As usual it's a matter of requirements. Before deciding for any kind of
script language you have to know who will be using that language. So far
I've worked on two projects where 100% of the game logic was made using
a scripting language: "Little Big Adventure" (LBA) and "Time Commando".
We know from the start for both those projects that a part of game coding
will be done by people with almost no experience in programming, so we
decided to make something very simple (and well, it was in 1995...) that
even a non programmer would be able to understand. And I have to say that
the result was ok. The game itself is perhaps not that good, but almost
everybody was capable of pointing out bugs in behaviors by looking into
the source code.

For those interested, here is the complete source code (I just translated
the french names in english for understandability) of the behavior of the
"Sabertooth tiger" encountered in the level 1 of Time Commando:

=====================================

StartProgram Tiger      // Last update Mike: Sun  02/06/96
    //
    // While the hero is not around here, do nothing
    // if the hero arrived at less than 2 meters of
    // distance, start roaring.
    //
    DoAnimRepeat    Nothing
    If GetDistance(Hero)>3000 AND !TestTouched
        SetBeta 460
        WaitDistance 6000
        DoAnimRepeat Walk
        Wait GetDistance(Hero) < 2000 OR TestTouched
        If GetDistance(Hero) > 2000 AND !TestTouched
            DoAnimRepeat Guard
            FollowHero
            DoAnimOnce Roar
            WaitAnim
        EndIf
    EndIf

    //
    // The hero is now in the fight area.
    //
    Loop
        FollowHero
        DoAnimRepeat Guard
        While TestAlive(Hero)
            distance_hero=GetDistance(Hero)
            If GetSameHit > 2 AND GetDifficulty <> 0
                Fury  Furie
                WaitAnim
                ResetSameHit
            ElseIf distance_hero > 3200
                //
                // At more than 3.2 meter, approach slowly
                //
                DoAnimRepeat Walk
            ElseIf distance_hero >= 3000
                //
                // Between 3m et 3.2m, use the long jump
                //
                DoAnimOnce GetValueList(-1, LongJumpAttack, Roar)
                WaitAnim
            ElseIf TestBetween(distance_hero,700,900)
                //
                // Closer, try to bite
                //
                DoAnimOnce GetValueList(-1, BiteAttack, Guard)
                WaitAnim
            ElseIf distance_hero < 700
                //
                // If too close for efficient hitting, get back or bite
                //
                If GetRandom(1)
                    DoAnimOnce Recule
                Else
                    DoAnimOnce GetValueList(-1, BiteAttack, Guard)
                EndIf
                WaitAnim
            ElseIf distance_hero > 1900
                //
                // At more than 1,90m, stay on guard
                // and from time to time launch a roar.
                //
                DoAnimRepeat Guard
                If !GetRandom(10)
                    DoAnimOnce GetValueList(-1, Roar, LongJumpAttack, Guard)
                    WaitAnim
                Endif
            Else
                //
                // Hand to hand distance
                //
                If TestHeroAttacking & GetRandom(1)
                    DoAnimOnce Recule
                Else
                    DoAnimOnce GetValueList(-1, ClawAttack, Guard)
                Endif
                WaitAnim
            Endif

            ExitProgram
        EndWhile
        UnFollow
        DoAnimRepeat Nothing
        DoAnimOnce Roar
        Wait TestAlive(Hero)
        ExitProgram
    EndLoop
EndProgram



=====================================

It will certainly not win any award for engeeniering quality, but
it was easy to code, easy to maintain, easy to extend.

Please note that the language as a very special notion of case
sensitiveness, that helps us a lot during production: It's case
sensitive in the meaning that when you write something in a certain
form, you have to use this form later. So it avoids people writing
"Hero", "hero", "HERO" to indicate the same thing... but there is
also a case insensitive check on each new encountered symbol, so
you cannot have to variable/keywords/functions/objects that have
the same name differently only by the case.


    Mickael Pointier