GPL Performance - Why does number of cars make such a drastic difference

Having just got GPL (pretty impressed so far apart form the average graphics which are a bit flat and lacking polygons and any real depth - can't believe you need a Voodoo 2 to push such simple graphics around) and I'm very puzzled by the framerate. I'm running a P200mmx with 64meg and a Creative Voodoo 2. With most graphics on I get 20-30fps whether I'm in 1024 or 800 or 640 (there is a difference but only a few frames). However when I put 19 cars in a session it drops to 6-12fps. This happens when the cars aren't even on the screen. If I put 10 cars out it's acceptable. Why do the cars make such a difference when the Voodoo2 is doing all the graphic work. I would expect slowdowns when they are on screen but not at other times. I remember ICR2 and Nascar2 having number of cars selectable but always thought it was for when they were on-screen (with rendition they ran like silk with everything on inc all cars anyway so I never used it). I've never seen this in any other racing game where it made any noticable difference. Any ideas. Dean P.S. I thought about the processor having to drive the cars off-screen but this wouldn't make sense to use up all that CPU power when you could use simple routines to work out where the other cars would be and only calculate the physics when they were in view.

Graphics aren't the problem. A Voodoo 1 gets 30+ fps most of the time with 19 ai cars in 640x480. You need more cpu to run the physics and ai. Games and systems tend to be balanced for a certain mix of graphics vs. everything else. GPL requires an unusual balance - heavier on the cpu side. rob. >Having just got GPL (pretty impressed so far apart form the average graphics >which are a bit flat and lacking polygons and any real depth - can't believe >you need a Voodoo 2 to push such simple graphics around) and I'm very >puzzled by the framerate. >I'm running a P200mmx with 64meg and a Creative Voodoo 2. With most graphics

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>on I get 20-30fps whether I'm in 1024 or 800 or 640 (there is a difference >but only a few frames). However when I put 19 cars in a session it drops to >6-12fps. This happens when the cars aren't even on the screen. If I put 10 >cars out it's acceptable. >Why do the cars make such a difference when the Voodoo2 is doing all the >graphic work. I would expect slowdowns when they are on screen but not at >other times. I remember ICR2 and Nascar2 having number of cars selectable >but always thought it was for when they were on-screen (with rendition they >ran like silk with everything on inc all cars anyway so I never used it). >I've never seen this in any other racing game where it made any noticable >difference. >Any ideas. >Dean >P.S. I thought about the processor having to drive the cars off-screen but >this wouldn't make sense to use up all that CPU power when you could use >simple routines to work out where the other cars would be and only

calculate >the physics when they were in view.

% Graphics aren't the problem. A Voodoo 1 gets 30+ fps most % of the time with 19 ai cars in 640x480. % You need more cpu to run the physics and ai. % Games and systems tend to be balanced for a certain mix of graphics % vs. everything else. GPL requires an unusual balance - heavier % on the cpu side. To add another note. . . Papyrus prides themselves (IMHO rightly so) on the extensive physics models in GPL. They opted to not compromise this and the AI must adhere to the same physics models as the human player's car. This requires alot of CPU horsepower. More AI = more CPU drain. Since the Voodoo cards tend to rely on CPU horsepower for calculating the graphics, you must share the CPU for graphics and phyics calculations. You may want to consider getting a Rendition card for 3D if you are planning on keeping your CPU for awhile. As the Rendition cards do most of the calculating required on the card and thus put less strain on the CPU. The Thriller seems to be the card of choice (outside 3DFX cards). -- **************************** Michael E. Carver ************************* Upside out, or inside down...False alarm the only game in town. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./. [- < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

Thanks for the info. I would have thought it would be easy to produce the same effect of drivers on different parts of the track without working out every bit of physics but there you go. Dean

The general view among the guys I race with is that actually, the AI don't run the same car model as the player (try swapping AI drivers between cars). It's reasonable, I don't want to waste my precious CPU cycles worrying about the shape of the contact patch on some car I'll never see again (until he laps me :O( ). Nonetheless, there does seem to be some slightly anomalous behaviour, the AI seem to be able to get a lot of acceleration at high speeds. Andy

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> >To add another note. . . Papyrus prides themselves (IMHO rightly so) on > >the extensive physics models in GPL. They opted to not compromise this > >and the AI must adhere to the same physics models as the human player's > >car. This requires alot of CPU horsepower. More AI = more CPU drain. > Thanks for the info. I would have thought it would be easy to produce the > same effect of drivers on different parts of the track without working out > every bit of physics but there you go. > Dean

I wondered why all top AI drivers in various cars (including eg. Rindt in Coventry) are able to reach 320 km/h or 200mph just before the Masta kink, while I can only push my Coventry to 305 km/h (the exit speed out of Malmedy is not that different). -- _____ /_______\ .\\ a t t h e a d I XT /~~~~ I 500\_____ 1977' Yamaha XT.Rex 500 Enduro \____/\__I_I http://matthead.home.pages.de/

says...

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>>Nonetheless, there does seem to be some slightly anomalous behaviour, >>the AI seem to be able to get a lot of acceleration at high speeds. >I wondered why all top AI drivers in various cars (including eg. Rindt >in Coventry) are able to reach 320 km/h or 200mph just before the >Masta kink, while I can only push my Coventry to 305 km/h (the exit >speed out of Malmedy is not that different).

With a light fuel load (enough to do one more lap) and warm tires, I can do 202 in an Eagle by the time i hit the kink. I often hit 200-201 in "short" races, and 199-201 in "long" ones. -- ========================================================= John Simmons - Redneck Techno-Biker (Zerex12) http://www.members.home.net/jms1/index.html John Simmons - Barbarian Diecast Collector http://members.home.net/jsimm/diecast_index.html IGPS Director http://members.home.net/jms1/igps.html If you want to send me email, go to either of the URL's shown above & click "Send Me Mail" in the contents frame. =========================================================

And there's me in my little ol' Ferrari doing a measly 196..... IGPS Spa will be fun :-) Cheers! Graeme Nash http://www.karisma1.demon.co.uk ICQ# 11257824 1998 Xoom GP2 League Champion

Belive it or not (most likely not but i really did do it) i hit 200 once in the Ferarri at Spa. My exit from Malmedy was really good though. Eagle im about 201 if i get a good run at it. My problem lies in the fact that i have to slow WAY down for Masta and Eau Rouge. Drives me nuts too cause i should (in theory) only be like 5-7 secs of the best laps at Spa (when i make it the whole way without spinning...which isnt often on a hotlap). But in reality im like 15 secs slower. Is it really possible for me to loose that much in just those two corners???

What kind of speeds are you running in the corners? Yesterday I turned a 3m19 lap in the Ferrari and dropped to a lowest speed of 123mph in Eau Rouge and 178mph in Masta. -- Cheers! Graeme Nash http://www.karisma1.demon.co.uk ICQ# 11257824 1998 Xoom GP2 League Champion

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>>>Nonetheless, there does seem to be some slightly anomalous behaviour, >>>the AI seem to be able to get a lot of acceleration at high speeds. >>I wondered why all top AI drivers in various cars (including eg. Rindt >>in Coventry) are able to reach 320 km/h or 200mph just before the >>Masta kink, while I can only push my Coventry to 305 km/h (the exit >>speed out of Malmedy is not that different). >With a light fuel load (enough to do one more lap) and warm tires, I can >do 202 in an Eagle by the time i hit the kink. I often hit 200-201 in >"short" races, and 199-201 in "long" ones.

In an Eagle with the same setup (slightly different transmisson), I can reach 321 km/h (200mph) too. But not in a Coventry. So I wonder how Rindt does it - does he get a better engine? -- _____ /_______\ .\\ a t t h e a d I XT /~~~~ I 500\_____ 1977' Yamaha XT.Rex 500 Enduro \____/\__I_I http://matthead.home.pages.de/