Re: [Plib-devel] Re: KobayashiMaru & plib

[Steve B. <sjb...@ai...>]

Alexander Rawass wrote:

> > > An actionbased flightsim doesn't need realism or accuracy
> > > at that high rates of speed.
> >
> > (Remember that I design flight simulators for a living - and
> > get paid six figures to do it - and now I'm telling you...)
> >
> >           You couldn't be more wrong.
> 
> Maybe we have a misunderstanding there.
> 
> What flight simulators do you program?
> 
> a) REAL flight simulators used to train pilots in military in civile
> b) good PC-Flight Simulators that I could buy
> c) action-based PC-'Flight'-Simulators

(a) Yes - mostly military fighters - F16's and F18's - but also
    attack helicopters, Stealth Fighter and F22.

(b) Yes - but only if you have $10M to spare!

(c) No - although I did write an arcade game flight sim (which happened
    to run on a PC) - I'll tell you more about that at the end of this email.
 
> if you're in a), I think you can't understand from what I mean, cause I
> will be doing c) with reality being stripped of like in those games.

The nature of the human perceptual system doesn't change.  If the terrain
doesn't have enough visual cue's for the speed you are travelling - then
your brain will mentally adjust the speed downwards.

I absolutely guarantee that you'd find one of our F16 flight sims more
exciting than any computer game you've ever played.  You come out of
the cab sweating, with wobbly legs - and adrenalin pumping.  Realism
rocks!

We have to *carefully* engineer our scenery to ensure that we have enough
cue's (rocks, trees, buildings) per square mile to ensure that the amount
of this "optical flow" is sufficient for the speed and altitude of the
aircraft.

This is hard to explain - but have you ever noticed that some cars 'feel'
faster than others?  When I'm driving my wife's miniVan, I continually find
that I'm driving faster than I should...it just 'feels slower than it is'.
That's because it has a high driving position - which puts you higher above
the terrain - which makes the small details of the road seem smaller (perspective)
and hence reduces optical flow.

That's why driving 60mph in a Porche seems so much more exciting than the same
speed in a school bus.

GoKarts (at just 15 to 20 mph) are amazingly good fun to drive.  A Porche at
the same speed is BORING!

...optical flow!

> > > Actually, we're not flying that fast, exept for hyperspace.
> > > A normal starfighter makes 1km in 10secs
> >
> > 360kph?  The Cessna's in FlightGear go faster than *that*!
> >
> > A 1970's F16 fighter can go about 5 times that speed.
> >
> > The space shuttle (when in orbit) has to orbit the earth ever 72 minutes.
> 
> Thats the point. I'n not going into realism. You'll be amazed how
> fast galaxies will rotate in the distance, and you'll maybe even see the
> rotation of planets - NO REALISM. Dump it.

Fine - but you said:

>>> You'll wonder how slow 'several times the speed of sound'
>>> can be in an action-type based game.

So I naturally assumed your planes would be a LITTLE more speedy
than a 30 year old prop-driven light aircraft!

Let me tell you two L-O-N-G (but hopefully instructive) TRUE stories:

You remind me of when I was working on a flight simulator *arcade* game
at Rediffusion about 9 years ago.  Because our management didn't think that
we "realism" fanatics could produce an exciting game, they paid Lucas Arts
(the StarWars guys) a small fortune to get one of their game design "experts"
to work with us as a consultant on "action and excitement".  I *hate* working
with consultants.

When he visited, I had just gotten the enemy aircraft "AI" working, and you
could dogfight with the other aircraft.  There was a problem (that I was
aware of) that the other planes were trying *too hard* to get away from
us - so they tended to always be rather further away than I'd like.

Mr Fox (the Lucas Arts guy) told us that the enemy planes (which happened
to be 'stealth fighters') were "too small".  I told him that they were EXACTLY
the right size for stealth fighters - but perhaps just a little too far away,
and he said that I was too hung up on realism and that he wanted more ACTION - so
bigger planes please.  We made the enemy planes 10% larger - then 50% larger - and
eventually TWICE the size of real stealth fighters.

Now this Fox guy (I forget his first name) said that the planes looked
about the right size - but why had I made them fly so slowly?  Once again,
I pointed out that these planes were flying at the EXACT correct speed for
a Stealth Fighter - and the REASON they appeared to be so slow was that they
were so huge that they traversed their own length (2x real size) in half the
amount of time that a real stealth fighter traverses it's own length. That's
why when you look up at a 747, travelling at half the speed of sound, it
looks like it's standing still. (Can you say "Optical Flow"?)

He insisted. I refused. He went to my managers - I got into a lot of trouble,
they said that he was the expert on excitement - and that I shouldn't get
hung up on this realism thing.  So I reluctantly doubled the speed of the
stealth fighters as instructed - and went home for the night.

As a result, the AI algorithms were able to fly the planes MUCH faster than
before - so they naturally ended up further away from the eye.

Fox comes in the next day - and flies into a total rage - telling my management
that not only had I slowed the planes down again in flagrant disregard for him
and management instructions - but I'd ALSO reduced them back to their original
size.  I got into MUCH more trouble - I tried to explain that I understood why
this was happening - but nobody would listen.  The aircraft sizes were doubled
AGAIN (so we now have fighters the size of jumbo-jets) - and then the speeds
were doubled AGAIN (so they are now flying at about mach 10 or so).

Now, Mr Fox turned his attention to the terrain.  Why had we modelled everything
so SMALL?  Well, of course everything was the correct size - but at Mach 10
and with fighters the size of jumbo's...the terrain did look pretty small.

It's that 'optical flow' thing...right?

Eventually, I came in late one night and changed the AI code so that the enemy
planes DELIBERATELY flew right in front of you - as close as they could
manage without you crashing into them or losing them in sharp turns.  I
restored the sizes and speeds to the real aircraft values - and everything
was fine.  Fox went back to California - convinced that he'd taught these
British 'realism freaks' a thing or two - and never knowing that the planes
were the exact size and speed that we'd originally had them and that we had
not in fact changed the scenery AT ALL.

*We* knew that SPATIAL/TEMPORAL realism was worth the effort.  What needed
to be changed was what went on in the heads of the other pilots.  The way
to make the player feel like a superhero is to make all the bad guys act
like klutzes.  My AI code ended up with the computer players TRYING to
get shot down by deliberately getting in front of the player and slowing
down.  Nobody ever noticed that they did that.  Everyone thought that they
were flying *SO* well!

If KJ is listening to this list still (I think he is) - he'll back me up on
that story.  Mr Fox was kinda infamous!

Trust me, flying in a realistic F16 is **WAY** more exciting than any video
game!  Fly one of our USAF sims - and you'll come out shaking and with white
knuckles.

I have a belief that in 3D (games or not), cheating realism will ALWAYS come
back to bite you.

If your planets spin much faster than real planets do - then you won't
feel like you are flying 200 miles above the largest thing you've ever
seen in your life. You'll feel like you are really close to a beach-ball.

When you try to land on the planet - that insane spin rate will require
that you match velocity at insane speeds - so you'll have to orbit the
planet once every 30 seconds instead of once every 72 minutes. When you
are zooming around the planet at that speed, it'll once again appear to
be stationary - but the supposedly stationary stars will be spinning
around you like a laser-ball light show!

You will find that you can't use real physical laws to make orbiting
work - because at those speeds, you'll fly off at a tangent.  So
you'll have to kludge that math too.  The kludges will pile higher and
higher until they show through into a really serious and unresolvable
logical anomaly that will prevent the game from working at all.

Better to start off with some reasonable premises and let it all 'just
work'.

Second story:

Do you watch StarTrek Voyager?  Watch the title sequence where Voyager
is flying above Saturn's rings.  Notice how the rings curve around
noticably?   Well, that's totally wrong.  In reality, they are twice
the radius of Saturn - I don't know how many thousands of miles that
is - but those rings would curve so subtly that they'd look dead
*straight*.  Because some artistic type at UPN thought that wouldn't
look right, they curved the rings quite noticably.  Because of that,
the rings can't be realistically WIDE either....and the planet
has to be much smaller so it fits inside the rings.

If the video sequence had continued with Voyager in orbit, you'd
have seen it clearly disappearing behind the rim of Saturn whilst
it was still quite visible...in reality of course, it would be
so small that you'd not be able to see it.  Saturn wouldn't look
like the second biggest planet - it would look like a beachball.

The way they built the sequence, all that cheating added up - HOWEVER,
they were able to pull it off by having Voyager do the hyperspace thing
before it vanished behind the planet and the trickery bit them.

In a game, you can't do that.  You'd end up with all the other
craft in orbit around Saturn being clearly visible from a point
just above the north pole because they are orbiting something
just 50 miles across !!

You really can't cheat spatially or temporally and get away with it.
If you want your spaceships to fly really fast and low - you have to
have them literally do that - and have the optical flow to back
that up.

"Be sure your sins will find you out!"

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
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