View Full Version : OT - game engines

09-06-2005, 06:23 AM
Anyone who's played 'Flat Out', the manic racing game, will have noticed lots of skid marks, dust, flying debris (barrels, tyres,fence panels - each with its own equivalent to an FM, plus multiple sound effects) water splashes, moving clouds, swaying blades of grass, most objects interactive and destructable with dozens of bits flying about when hit. There are loads of cars racing against you, each with its own authentic look and impression of weight or inertia, plus some excellent sounds. Light reflections dazzle and sparkle - the list could go on . . .
My question is: why can most folk run this game with all its complexities on any old basic system, yet something like IL2 which, on the face of it, doesn't have so much going on at the same time on screen, can cause such problems for lower end systems? Is it the game engine that's so different - and if so, would the engine used by the Flat Out developers not be more suitable for flight sims?
This isn't a moan as I have quite a high end machine and thoroughly enjoy IL2 in Perfect mode, but recently having a quick race in Flat Out, I started wondering. I'm simply curious why game engines differ so dramatically and have always wondered how Flat Out's amazing performance can be achieved when some flight sims struggle.

09-06-2005, 06:30 AM
Visible terrain in the racing game is only a few hundred metres. In the flight sim it's measured in tens of kilometres. Even though the racing game has a high number of close objects to calculate, the total number of objects in the visible area is small compared to the flight sim, particularly once you have hundreds (in some cases thousands) of bullets with ballistic trajectories to calculate.

This is only one of many differences in the complexity required between a racing game and a flight sim.

09-06-2005, 06:44 AM
Let the programmers explain it, but it's more differnt than apples and oranges, with FM differences between Gladiators and TB-3's, DM's like the Zero and Fw-190, guns, ammo, armour, ballistics, ships, tanks, trucks, trains, propellers, torque, fuel leaks, fires, gun turrets, bombs, altitude, and so many more I can't even think of.

09-06-2005, 06:59 AM
Guess I never considered the distance factor when thinking about this, although some of the racing games are rendering a theoretical mile or so virtual distance rendering, with all those trees and blades of grass wafting about in the breeze.
However another comparison is perhaps the arcade game Heroes of the Pacific (I think?) demo I downloaded just to see what it was all about. The FM was dreadful - or non-existant might be a better description, but the graphics were very well done. The Pearl Harbor map was full of buildings, ships, water (obviously) with A/A fire/tracers going in all directions. The enemy planes were all over the shop with their own trails of smoke and flame when hit. It was obviously an arcade game, but had they put brain in gear and made the flight model realistic, the potential was there for an interesting sim, if nothing else. The fact that it could again run on low-end systems with all its special effects taking place made me similarly wonder about its game engine's abilities - quite similar in quality to Flat Out.

09-07-2005, 01:33 AM
Although Heroes in the Pacific does some funky graphics processing, one of the reasons it's able to do that is because it's not doing the complex FM and ballistics calculations that IL2/FB/AEP/PF is. The developers of that sim have chosen to sacrifice complex flight modelling in favour of eye candy.

09-07-2005, 03:00 AM
I think it's pretty much of the coding of the engine too. If looking back to the date the original IL-2 was released in 2001, it ran considerable well on mid-level PCs with maybe the best graphics of that time. Its engine just isn't up to this day's standards anymore with all that new stuff. But if compared to about the same age OFP engine, the IL-2 engine still rocks. OFP's graphics were outdated already when released and even today it's very easy to put this day's high-end machines on their knees with it (the game still rocks though http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif )
I wouldn't too much compare IL-2's engine and Flat Out's engine since in those years they differ in age, coding techniques and methods have developed and backed up with new technology. It's not only how much the engine has to calculate, but also how it calculates.
PF's engine has got a facelift, but it's still based on that old one, which clearly is a burden.

09-07-2005, 03:31 AM
Hi Porsimo, your comment was interesting. So the way the engine is put together, coded, whatever, affects the performance even on a newer machine? PCs nowadays are considerably more powerful compared to those around when it was first made but are you saying they can't just "brute-force" it and run it on Perfect with everything maxed out because it is put together badly (by today's standards)? I know nothing about programming at all. I just assumed that a new PC would be able to run it perfectly.

09-07-2005, 04:10 AM
I just assumed that a new PC would be able to run it perfectly.
It would if that were the only change. When IL2 Sturmovik was released, many gamers were still using trimmed down Win98 installs. Now we're mostly running WinXP. The later operating system is vastly more stable but it demands considerably more system resources, so the performance improvement is not as great as it might have been.

09-07-2005, 07:14 AM
Well, it isn't quite that simple as almost all things affect to another. And it's not the case of bad coding either (well, Operation Flashpoint engine IS an example of bad coding). I think IL-2's engine is very good, but it's over 4 years old and it has to run several things that weren't maybe meant to be included originally, when the engine was coded. "Up today's standards" practically means today's (demanded) graphics and other stuff as in many cases the engines are coded few years ago for tasks less demending than today's.
Plus the operating system as Tully mentioned. E.g. XP eats memory for breakfast and continues from there... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

09-07-2005, 08:32 AM
Do we know why XP eats so much memory in its basic functioning? Is it possible to set up a cut-down, games-specific version of XP - a bit like a racing car with all unnecessary bits and bobs stripped away, just leaving enough parts to operate games and nothing else?
My games machine isn't internet connected and I wonder how many processes it runs up front and in the background purely to assist internet browsing/communication etc. I have no software on it other than games so could any of its facilities that require RAM just to tick over be scrapped?

09-07-2005, 09:19 AM
One way to reduce the usage of memory in XP is to tone down all the candy in the interface:

- Right click My Computer and select Properties
- Open Advanced -tab (? I don't have English XP so I'm not sure about the caption)
- Click Settings in Performance frame
- Select Best performance and click Apply

Depending on system and all the drivers etc. the reduce of memory usage may be in tens of megs. Or maybe only few megs..

09-07-2005, 09:22 AM
Thanks Porsino and Tully. That was interesting to hear. Any guesses on when or what kind of system we'll need to be able to run this with a large number of planes maxedout on all settings? Kind of makes me nervous about BoB. It's a good kind of nervous though.

09-07-2005, 06:09 PM
There is a way to free up some of the memory that XP devours, as long as you're careful.

A little application called FSAutostart (check Bearcat's sig for the Essentials thread), originally developed for MSFS2k4. Basically what it does is allow you to taylor select any bunch of programs and services that windows has running in the background, and shut them down temporarily while you're playing your game. After you close the game it restarts the services/programs (with probably an 85% success rate - some services just don't like restarting with out a computer reboot).

I freed up 150MB of RAM on my 1GB machine (since then I've upgraded, but it definitely helped a lot when I needed it), using FSAutostart (from 700MB free to 850MB free). FS Autostart also defragments the RAM before play to improve access speed and performance.

I say that you have to be careful with it, because you need to make sure you don't shut down anything used by the game. FSAutostart has a 'hint window' that tells you which services you should definitely NOT shut down (for system stability), but there are several that Sturmovik uses that you don't want to shut down as well. For network play, I didn't get a stable connection until I made sure that ALL the network services were free from shutdown. That included NetBIOS (strange, I thought), and even file and print sharing.

However, the BIG RAM eater is Microsoft Themes (the thing that makes your desktop look like XP rather than 2000), and you can safely shut that down (among many other things) and restart it after play.


09-08-2005, 03:51 AM
Thanks for the response.
Given that my games machine isn't connected to the net and I therefore obviously only play offline, presumably I can switch off all Net activities or functions pretty much permanently?
Are there any background net-based activities going on by default that XP still needs in order to function properly, whether connected or not - a bit like buying a mobile phone that has a camera built in even if you don't want to use it . . .