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Drew Carey
12-07-04, 10:08 AM
Hi guys,
I'm searching for info regarding the various graphical engines featured in recent games (Quake, Unreal, DoomIII, Source, CryEngine, TotalWar etc) and was wondering if guys might know of any articles to talk specifically about one and it's features. I'm especially searching for info like polycounts, texture sizes, map and shader types and all that stuff used in the games utilizing these specific engines.

Any help would be great.

Subtestube
12-07-04, 04:11 PM
Start here, if you haven't already been there. It's not quite what you're looking for, but it's fairly comprehensive. In my experience, if you want REALLY detailed info, you'll probably need to contact the engine owners.

http://www.devmaster.net/engines/

SH64
12-07-04, 10:49 PM
Woah nice link there Subtestube !

i also might add some :

Serious Engine 2 info (http://www.croteam.com/)

Source Engine info (http://tjs.5u.com/catalog.html)

& i have a couple of pages stored on my HDD about Painkiller & Doom3 engines thats are not up anymore . i can send them to you if you like .

jbirney
12-08-04, 01:10 PM
Keep in mind the graphic rendering is only one part of the engine. You also might want to look at other things (BotAI, Physics,ect). Also with mods being as popular as they are, maybe check out the modding ability of them as well?

Drew Carey
12-09-04, 07:52 AM
Thanks for the info guys.
I'm writing a paper about the implementations of computer graphics, so I'm searching mainly for info about the graphics side of the engines. I'm focusing most of my writing on FarCry, DoomIII and Halflife2.
If anyone has any more info on these three engines it could be really helpful.

SH64
12-09-04, 06:30 PM
Heres an informative article on FarCry engine :

Far Cry Long Range Gameplay + Polybump Technology Q&A

Developer: Crytek Studios
Publisher: Ubi Soft Entertainment
Release Date: March 2004
Genre: first-person shooter
Website: http://farcry.ubi.com/
Downloads: http://www.3dgamers.com/games/farcry/

Your name? Christopher Natsuume

Your role in the development team? Lead Producer

1. You said Far Cry proposes a unique range of view. What does this
exactly mean? What is your goal behind this concept?

A: The "goal" was never long range gameplay in itself. We started
with the idea that we wanted a completely different feel in the game,
and we determined that a massive outdoor tropical environment was
something that had never really been done well in a FPS game. We had
seen too many games with dark corridors; we created a beautiful widely
appealing outdoor environment for Far Cry, a contrast to the current
market FPS games. Because of this decision, long range gameplay,
non-linear level design and adaptive AI grew as an organic design
need. It was either that or create "indoor" outdoor sections, where
the player is still confined in a box, even though he is supposed to
be outdoors, and this was not appealing to us.

2. Can you please tell us how far this range would represent in
real world?

A: The horizon, essentially. But in a game, this can be substantially
over a thousand meters. More importantly, it is so far that even on
a high resolution monitor your enemies are essentially a pixel until
you use some sort of long-range viewing device, like binoculars or a
sniper scope. Much more long range than this didn't really make much
sense to us.

3. Could you please explain what will be the implication on gameplay
then?

A: The gameplay adjustment is more than just being able to shoot
extreme ranges (which you can do). More importantly, it means that
this whole massive area is open to the player for exploration. We can
give the player a lot more freedom in where they go and what they do,
because they can see further and make long-term strategies. Also,
getting across these spaces takes time, so we have a more urgent need
for vehicle use, and this makes for even more gameplay options.

4. Does that mean that there will be none or only few in-doors
environments?

A: Not at all - we have indoors, but even there we have gone larger,
open spaces, interspersed with small creepy spaces that provide
contrast. But the majority of our game is outside. If you went to a
tropical island, you wouldn't want to stay indoors the whole time,
would you?

5. What was the technological challenge of such a long range?

A: Most obviously, more view distance means more to draw - which
traditionally means a lot of memory and CPU usage. We have solved
this through using an optimized height-map terrain mixed with geometry
that uses our PolyBump technology, occlusion culling, and active LOD
(Level of Detail) technology to draw only what is necessary.

Less obviously, we had a serious challenge in creating an AI that
worked with the kind of player freedom allowed by these spaces, and
which could respond to long range threats and use vehicles dynamically
as the player does.

6. Binoculars aside, what kind of long-range equipment and weapons
shall we find in Far Cry?

A: Well, we have some long range weapons with scopes, as well as a
motion tracker and sound enhancer to let you find, hear, and kill
things from a long way off. We also have some mounted weapons that
work at long ranges, and some vehicles that allow you to go a long
way in a hurry.

7. Do enemies benefit of very long range weapons too? If yes, how
the player will be able to prevent long range attacks?

A: Absolutely - it's a major part of the game. The world is full of
hard and soft cover, and the player has radar he can use to help him
identify threats. Using these in combination he can minimize long range
threats until he can position himself to take them out. But attacking
and being attacked from range is a major part of the overall game.

8. Does long range means that player can go anywhere he can see?

A: It is a mantra for our design team: "If it looks like you can go
there, you can." We have followed this very strictly, and despite the
pain and suffering it has caused the design team in our level design,
it is one of the most critical decisions we have made in defining
the overall feel of the game.

9. Can you please explain the history of Polybump technology? How
did Crytek have the idea to develop Polybump technology?

A: When we were in early development, we knew that we would face issues
in putting together the kind of massive terrains and environments we
needed, especially with interesting and detailed characters, unless we
found some innovative solutions to rendering. Cevat Yerli, the founder
of Crytek, worked back in January 2001 with Marco Corbetta and Martin
Mittring - two key coders here - in developing not only the PolyBump
technology, but the Dot3 Lightmap technology that works with it.

10. Could you please give us more explanations about this
technology? How does it work? What are advantage and risk this
technology included?

A: The key idea to PolyBump is deceptively simple. First we make
a very high poly model - most of our characters are about ~400,000
polys, but some go up to a million or more. We then take that mesh
and transform it into a complex "normal map" - which is a map showing
how light should reflect off of all of the details properly on a
per-pixel basis. We then use that normal map as a sort of "lighting
calculation texture" on a low-poly model - in the case of most of
our mercenaries 2,000 polys. This means that as we move this model
beneath a real dynamic light, we see the light change as though all the
original details were actually in place, when the model is actually
much simpler. The end result is a character (wall, machine, vehicle,
etc.) that looks like it was a million polys, which is actually much
simpler. This means we can use a lot more of them, in an environment,
and more lights with them as well.

The big drawback, of course, is that this only works when we use
real dynamic lights - because the details of a PolyBumped object are
essentially built from their interaction with the light. This is why
we developed the Dot3 Lightmapping technology, which is a new way of
using traditional lightmapping technology with per-pixel lighting
to create a vivid lighting model that still lights the world with
an infinite number of lights that can express the PolyBump normal
maps. Lightmaps and Bump-Mapping were mutually exclusive to each other,
but our patent-pending dot3-lightmap technology makes this possible.

11. Polybump mapping technology is quiet impressive. Which way do
you plan to utilize it in the game: do you want to create extremely
detailed characters, or to bring a really big bunch of enemies moving
on the screen?

A: Yes and yes. The beauty of PolyBump is that we can do both. We are
very close to the limits of visual acuity on your monitor with our
characters, and we can still have a dozen or more of them actively
moving around on screen - even in massive environments with a great
deal of detail.

12. How does the engine manage such huge maps in real time, regarding
the quality of textures? Does it limit the treatment of physics for
mapped objects?

A: The big maps are an issue, but the more important issue with the
current technology is not how much stuff you have on screen, it's how
many times you draw it, essentially the fillrate problem. Most special
effects, such as alpha blended particles or vegetation, reflections,
blur, and especially dynamic lighting creates second, third, sixteenth,
etc. passes on each pixel - meaning that the computer has to calculate
what to draw on that pixel numerous times. It's called overdraw,
and it is the real limiting factor in massive environments with
lots of vegetation and special effects like ours. We sort this out
through judicious use of certain shaders in certain environments,
and tech-friendly level design.

As for physics, we have a sort of Physics on Demand system, which only
activates "physicalized" objects when interacted with. This means
that the limiting factor in "physicalized" objects is not how many
there are on a level, but how many there are in an area where they
might all be activated at once and interact with each other. Since
this limit is a hundred or so relatively complex objects, we can
pretty much fill the whole world with "physicalized" stuff.

13. Polybump allows very detailed facial expressions: should we hope
to have NPC interventions in-game?

A: The characters in the game all have complex facial structures, and
use them in facial expressions and to talk to each other, but in all
honesty, you do a lot more shooting than talking than Far Cry. We do
have some places where you will interact and work with NPCs though,
such as the lovely photographer Val and the mysterious scientist Doyle.

14. Thank you for the answers!

A: No - thank you. It's the hard core gaming audience and the press
that keeps it informed that allows innovative games like Far Cry to
be made. Without you guys, we'd be making database software dreaming
of making something this cool...

Drew Carey
12-10-04, 03:30 AM
Thanks man, very helpful.