Terrain
The newly-designed scenery for FS2000 has changed so
dramatically that you might not recognize the world you've flown so
many times before. It seems as though both the visible and
behind-the-scenes treatment of the FS World has experienced some
major changes. Whether daytime or night, summer or winter, the
appearance and behaviour of the scenery are all new.
Andy: We have taken the whole terrain model that was
there and threw it away! The whole scenery engine, soup to nuts,
from getting the stuff off the disk to pushing the pixels onto the
screen. There is not a stitch of old code left in there.
Scot: Actually Dan, the software renderer was done by a
guy whose name may ring a bell with you since you come from the
game community – Michael Abrash 'Father of the Polygon'. He’s just
down the hall here! He built our software renderer from the ground
up. Its a wonderful piece of work.
Andy: So, there was not much point in rewriting the whole
thing unless it did something new and interesting and of course the
big headline is the new terrain. The whole world is covered to1
kilometer or higher resolution with digital elevation match. That
gives you the shape, then you’ve got to texture it with something
so the same resolution as a world-wide land class map. In other
words: what is the that piece of earth used for? There is an
extensive list of different classifications that we get from
various sources, governmental and otherwise, so that covers the
whole world.
The dynamic scenery system in Flight Sim 2000 is basically the
same as what was there in FS98. To add objects to the scenery
information is explained in the scenery SDK that is out there.
Scot: We are not shipping a tool for doing Dynamic
Scenery however.
Bruce: The SDK we provide basically as information: its
not tools – we publish, for example with the scenery, we publish a
lot of detail about the file formats but you have to be this tall
[hands held up] to use that tool. You’ve got to know what you are
doing. As Andy said, we did not aim it at the end user but to the
developers who understand how to code.
Andy: I can tell you a little more about the terrain.
There is a bunch of things that come for free with that, so its not
just a static map of the world. Depending on what the capabilities
of your system – for example lets say you have a square that says
'this is urban'. You don’t always see that same urban texture. We
have multiple variations of 'what urban looks like', so the
net result is in a large area of urban land. You don’t see
repetition over and over again of the same title with exact square
boundaries, so there’s variations that get used.
Then there’s something else, which we call transitions. There
was an early form of this technology in Combat Flight Sim. But
anyway, when you make a switch (let's say) from urban to farmland,
if those two titles butt right up against each other you see the
lines in older version. We build textures in memory on the fly to
make a smooth transition from one to the other. So you never see a
hard line between the two different types of terrain.
When you combine all this information, we can scale this
depending on the memory your machine has, how much memory your
graphics card has, so at the highest end you see something that
looks like what we show on the screen shots that blows you away. At
the lower end you still get the performance and all the benefits of
that new terrain engine but we scale it appropriately to the
capabilities of your machine so we're not bogging you down with 64
megs of textures on a 16 meg machine.
Scot: This is also scaleable upward, we are actually
capable at this point of delivering a level of graphics fidelity
that will literally choke the highest end machine that is available
right now. But when those machines are available Flight Sim will
look that much better. So the knob goes both ways!
Andy: You get a bunch of other things for free. For
instance the seasons change. Some people used to complain that if
you change the settings in Flight Sim, say to winter, then nothing
looked any different. All the textures will change appropriately
now. Winter actually looks like winter, the farmland isn’t green in
the winter and you do see some snow on the ground.
Day and night, there are some great effects. First off, because
the terrain is not flat you will see all the proper
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Night approach. Note instrument
lighting
and ground lighting effects.
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shadows cast depending on where the sun is in the sky. The
astronomy is all correct and accurate, the sun and the moon will be
in the right place at the right phase (Scot: As will the
stars), the stars are accurate, they're at the right place in the
sky depending on where on the Earth you are. The shadows of the sun
cast fill-in. If you go look at Mt. Rainier at 9:00 A.M., all the
shadows are on the left side of the mountain. Then if you ratchet
the clock around, the shadows all move to the other side. You get
these valleys with lighter and darker bits. When it starts getting
to night time, we start modulating in night time textures, on top
of the day textures and the day textures start to gradually get
darker and darker. So you have this multi-layer scheme going on and
then when its finally completely dark, we just don't use the day
texture at all anymore, now it's all night. We do the reverse
process (Scot: it looks like the lights coming on and it's
pretty spectacular) at dawn. All of these things just sort of fall
out of this new terrain system. |