Thoughts about a slipstream-editor

Hello to all,

one of the very few things to regret on GP4, in my opinion, is the insufficiency of the slipstream in-game. Especially on oval courses like Rio or Indianapolis you can see that the effect of drag reduction due to the slipstream doesn't last very long (about 50 meteres, respectively 0.2 sec.). Much more realistic it would be, if the slipstream would still work of about 200 meteres, respectively 1 second behind a frontrunning car with a descending effectiveness.

So, it would be great to have a tool to tweak the game's slipstream in terms of length and strength. I know, there hasn't been that much work into this direction, so far. But maybe some modders will have fun to work on it. All I know is that the slipstream strength has been decreased notably from gp4.exe version 1.00 to version 1.02. So it might be at least possible to detect, where the slipstream is 'produced' inside the code and maybe we can modify it even with an hex-editor. That would be great. Of course, I'm ready to serve as a test driver, if there is any need for it.

Note:
This is no offence nor order to anyone. I'm just hoping someone feels like working on it . That's all.
Thank you!

You can edit slipstream with gp4tweaker, at least some version had that opinion and it worked fine in some areas.



Edited 1 time(s). Last edit at 04/05/2022 04:57PM by vesuvius.

vesuvius schrieb:
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> [...]

I think you are talking about a tweak most wrongly called 'slipstream effect'. This name is completely wrong, because it has nothing to do with the slipstream at all. Not with it's length, nor with it's strength. It's simply a 'dirty air-effect' and the creater would have done better to call it like that.

But no, this is not, what I'm talking about. My request aims towards the clean slipstream (air drag reduction), not towards the dirty air. I would like to have a tool to tweak the length and the strength of drag reduction.

Sounds like an excellent idea klausfeldmann.

A friend and I were discussing 'dirty air' the other day (ie how it's more obvious in some mods than others), but we never made the connection to the so-called slipstream effect. I've a feeling you're absolutely right though; so thanks for the insight.

I'm now wondering if desc=45 or 46 (drag and player downforce) or even one of the 'unknown' values in the magic data file might have an impact on real slip-streaming? I've never noticed anything before, but it might be hard to spot unless you were specifically looking for it - and any excuse to have a quick blast on an oval track is good enough for me!

Noog schrieb:
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> I'm now wondering if desc=45 or 46 (drag and
> player downforce) or even one of the 'unknown'
> values in the magic data file might have an impact
> on real slip-streaming?

If I would have coded GP4, I had put all slipstream-related variables hardcoded into the executable, because in my opinion there is no sense, to put them into the track-related data. Slipstream works in the same way on every track, so putting these data into the tracks would be redundant. Probably no good coder would do that.

Nevertheless, after your post, I had some extensive tests of several magic data variables at Rio Oval. It took me some hours of testing, but at the end, I cannot say that there is any influence of the tested magic data variables on the slipstream, neither for the player, nor for ccCars, neither on the strength of slipstream, nor on it's length.

Also the defensive behaviour of ccCars obviously is not influenced by the tested variables (there where some speculation about desc49 and cc-defensive behaviour in the past), neither on the event which triggers the ai to defend it's position (going onto the inside line before a turn), nor to the broadness of the track used for these defensive maneuvers (would have made sense to me, due to different tracks having a different degree of broadness, but no...).

Tested magic data variables where:
; desc38= unknown
; desc39= unknown
; desc40= unknown
; desc41= unknown
; desc43= unknown
; desc44= unknown
; desc45= Temperature (deg C) - top speed only affected, minimal effect in corners / acceleration? (17 - 31)
; desc46= Air Pressure (hectopascals). AFFECTS PLAYER-ONLY downforce, and drag
; desc47= Engine power output - e.g. altitude simulation? Affects acceleration
; desc49= Slipstream? A distance in feet that is subtracted from the distance between 2 cars, then compared to the speed(?) of one of the behind car, and if the speed is less, something is triggered. Player only.

As a result of my tests, I just can confirm the meaning of the descriptions 45 to 47. But the meaning of the variables 38 to 41, 43 to 44 and 49 still remain unknown to me.

So, sadly, we still have to look for the slipstream variables used in-game inside the executable file, in my opinion.

klausfeldmann Wrote:
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> If I would have coded GP4, I had put all slipstream-related variables hardcoded into the
> executable, because in my opinion there is no sense, to put them into the track-related data.
> Slipstream works in the same way on every track, so putting these data into the tracks would be
> redundant. Probably no good coder would do that.

Makes sense. I did consider that after I posted, but I wasn't sure; so thanks again for the confirmation.

> Nevertheless, after your post, I had some extensive tests of several magic data variables at
> Rio Oval. It took me some hours of testing, but at the end, I cannot say that there is any influence
> of the tested magic data variables on the slipstream, neither for the player, nor for
> ccCars, neither on the strength of slipstream, nor on it's length.

Oh well. I guess I'll have to find another reason to load up an oval. Shouldn't be too difficult...

> Also the defensive behaviour of ccCars obviously is not influenced by the tested variables (there
> where some speculation about desc49 and cc-defensive behaviour in the past), neither on
> the event which triggers the ai to defend it's position (going onto the inside line before a
> turn), nor to the broadness of the track used for these defensive maneuvers (would have made sense
> to me, due to different tracks having a different degree of broadness, but no...).

I suspect your investigations are far more methodical, thorough and better informed than mine, but I've never stumbled across any ways to affect defensive (or attacking) behaviour either.

> Tested magic data variables where:
> ; desc38= unknown
> ; desc39= unknown
> ; desc40= unknown
> ; desc41= unknown
> ; desc43= unknown
> ; desc44= unknown
> ; desc45= Temperature (deg C) - top speed only affected, minimal effect in corners /
> acceleration? (17 - 31)
> ; desc46= Air Pressure (hectopascals). AFFECTS PLAYER-ONLY downforce, and drag
> ; desc47= Engine power output - e.g. altitude simulation? Affects acceleration
> ; desc49= Slipstream? A distance in feet that is subtracted from the distance between 2 cars, then
> compared to the speed(?) of one of the behind car, and if the speed is less, something is triggered.
> Player only.
>
>> As a result of my tests, I just can confirm the meaning of the descriptions 45 to 47. But the
> meaning of the variables 38 to 41, 43 to 44 and 49 still remain unknown to me.

Thanks for confirming those; fascinating. Such subtlety (ie, temp, altitude AND air pressure), would seem to suggest to me that something as fundamental as slip-streaming must surely have been given a tweakable value somewhere.

> So, sadly, we still have to look for the slipstream variables used in-game inside the
> executable file, in my opinion.

I agree completely, but unfortunately editing exes is well beyond my abilities. That said, I'd certainly be very interested in any discoveries you might make.

Noog schrieb:
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"Such subtlety (ie, temp, altitude AND air pressure), would seem to suggest to me that something as fundamental as slip-streaming must surely have been given a tweakable value somewhere. [...] Unfortunately editing exes is well beyond my abilities."

Of course, there will be any tweakable variable inside the exe, for sure. My abilities in analysing and changing a reversed exe in assembler language also isn't quite well. A few years ago, I wrote to SDI and asked him, whether he could have a look onto the slipstream in the source code. He wrote it onto his wishlist for the gpxPatch. Sadly, he retired some time ago.

Hey klaus. You've mentioned that the GP4 tweaker feature should be renamed to 'dirty air' but how does it work at all and how does it affect the AI cars?

___________________________________________________________________________
For a list of EVERY download for GP4, look here:[docs.google.com]

Soutsen schrieb:
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> Hey klaus. You've mentioned that the GP4 tweaker
> feature should be renamed to 'dirty air' but how
> does it work at all and how does it affect the AI
> cars?


Hey Soutsen,

here is all you have to know about the slipstream (dirty air) effect tweak:

How to make it working?
Probably you know, that you have to install a tool named "GP4 Tweaker Personal Edition" (not equal to the simple GP4 Tweaker!) and make sure the slipstream.ini is enabled in the gp4tweak.ini to get the slipstream (dirty air) effect working.

How to tweak the dirty air effect in general?
In the slipstream.ini you can set different values to tweak this effect. There is one value for the car's front, car's rear and car's downforce in general, each. All values are in percent. These percentages determine how many downforce your car will lose behind another car. For example, if you set a value of 15% for the front and 30% for the back, your car will lose 15% downforce at the front and 30% at the rear, if your car is close enough behind another car. These exemplary values would lead to a high degree of overseer, especially at high speed corners. To avoid your car losing the balance, I always recommend to set both values (front and rear) to the same amount.

What values are recommended?
This depends on how difficult you want overtaking to be. I use 35% for front and rear, and 3% effect in general. This makes it quite hard to overtake, but not impossible. Values of 40% should be the edge of realism to me. Higher values would make overtaking completely impossible, IMHO.

How does the effect work at all?
If you mean by this question, how it interferes with the GP4 source code, I have no knowledge about it, sorry. All I can say, that the effect works higher the more speed your car is driving and the closer you are to another car. And, in addition, in practice sessions it also works much much much higher (already if you are about 2.5 seconds behind a car), than in race sessions (about 0,5 seconds behind another car).

How does it effect the ai cars?
This is subject to contorversial discussions. Some user say, it works pretty good to ai cars, as well. Some say, it doesn't work for ai cars at all. The results of my tests were that ai cars are somewhat uneffected or at least very much less effected, than the player's car. I for my part would say, it does not work for ai cars at all (although there is an option for it). To test it yourself, set all values to 100 and see what happens.

I hope, this answers your questions. If there are any more questions, feel free to ask them .



Edited 1 time(s). Last edit at 05/18/2022 06:54PM by klausfeldmann.

Yeah, it's just Im trying to figure out what setting are available in terms of applying them to separate cars, not the MD values for example which apply for the whole field. I started a topic for this one but noone replied yet. Have you tested the GP4 Tweaker Tool (not personal edition) pit-stop timer settings? I'm low on free time atm so cannot spend too much time on figuring the basics on my own. Also would be nice if you would say what else do you know in terms of editing GP4 to make AI cars to act different from one another, cos I feel like this is a great game for the AI race simulations and making such series as GPGSL or others, maybe even more advanced

___________________________________________________________________________
For a list of EVERY download for GP4, look here:[docs.google.com]

I completely understand your will to make ccCars behave different from each other. These are really great tools, SDI and other modder implemented to GP4, so far. As any user said about it: "This adds personality to the game." The slipstream (dirty air) effect would also possibly create a difference between the ccCars - at least, if you are able to make it work for ccCars (as I'm not).

I didn't use the pitstop timing-tweak of GP4 Tweaker Personal Edition, so far. The only thing I used was the "normal" Pit stop tweak of the "normal" GP4 Tweaker, but that led my game to crash as it is warned in the tweak discription, so I didn't experiment with it after that.

Yes, I saw your other thread, of course. As I'm a little bit short on time, I will answer to it tomorrow or at the upcomming weekend.

Yeah, it's all fine. Probably there are not much ways of altering the game in the way that I somehow do not know yet after all these years of playing and learning about the game. I remember there was tons of different tools in the beginning like in 2005-2009 with many of them needed the site generating the serial-code for them and were called something like GP4xWhateverxEditor and I think jurgen (aka quickslick) can still have some of them on his discs but I'm not sure if these were able to alter the CCcars perfomance, not just altering the usual set-up of the player car. This is one of them:
[www.grandprixgames.org]
But if there are any of such editors are avaliable for the CCcars I'd like to know about them

___________________________________________________________________________
For a list of EVERY download for GP4, look here:[docs.google.com]



Edited 2 time(s). Last edit at 05/20/2022 10:28AM by Soutsen.