I have done quite a few but none better than this ultra simple one that adds rotational friction to the wheels.  Before, if you were on level ground, you could coast forever after letting off the throttle.

Neat, I'll try that one.

I had once started work on a system that allowed you to equip weapons on the car, for a car deathmatch type game (Streets of SimCity, Twisted Metal, Full Auto, etc). It never got far since I couldn't get JigLibX to play nice with the GameStateManagement sample... Did you get that to work?

I haven't used that sample.  What was the problem you were running into in that sample?  

Well, that nothing was being rendered except for a blank screen, for one. I could never figure out what was going wrong... I'll have to take a second look at it now.

I had looked at the InnovativeEngine before, but it doesn't support CarObjects out of the box. What did you do to add them?

(now keep in mind I had tried this a while ago when I didn't know much about camera matrices!) I can't believe how simple it was. I hadn't added the player's car object to the list of objects to update, so the chasecamera wasn't being updated which is why the screen was blank - the camera was underneath the terrain pointing the wrong way. :-P Maybe now I'll continue work on my Streets of SimCity type game...

Well, sorry to derail your thread! I'm interested too in how other people are using JigLibX.

That's good.  As far as CarObjects in Innovation Engine I started working on my own CarActor class and then someone posted their own in the forums.  I just used theirs.  

Proper Hand Brake and Top Speed Adjusment *updated*

Interesting.

nikescar:

Next time I'll go into what all the CarObject settings do as well as a few new tweaks to the car class.

Please do. Did you get to solve the problem where at high speed straight driving, the car starts wobbling left-and right, which causes some bad behavior?

Nice samples (but your changes don't appear in red).

I spent half the day yesterday playing with the car class in JigLib and spent a few hours just working on drifting as it's one of the main features we want in our game.

I saw that some people were having trouble with that and there's a few different ways to fix it.  

Ooh, very nice! Drifting is my favorite thing to do in "real" racing games. Can you do my second favorite thing with that setup; donuts?

You can tweak some of the settings to get some pretty lousy donuts but the way the car physics are written it's not that great.  I've looked into changing the slipVel variable around to make it more realistic but I'm not quite there yet.

One of the guys at my work (Alexis Drew) is a drift racing champion, he apparently holds some record for doing donuts too. I've not tried to do any in my game, but since I'm using only a slightly modified JigLib car class then probably can't do them very well.

I finally got some time to play with this. I've implemented your changes and it is very drifty! :-)

One thing - is there an easy way to modify acceleration and top speed? It's really sluggish with this setup. I've tried modifying the torque and the wheel friction values, but nothing works well (although I got it to speed up really fast and then immediately flip and roll over when I turned slightly - hilarious!). How are you doing it?

...Too bad more people apparently aren't modifying this. When I get further along I'll post screens of what I'm using it for (hint: Streets of SimCity was one of my favorite games).

This is something I've been working on between struggling with gamestate management.  I've updated the Hand Brake post to include a topSpeed variable.  Don't miss the part about the gravity. 

Acceleration is another issue.  I'm having trouble getting this to work the way I want it.  I'm working on it though.

I promised a commented out vehicle class and I am working on it.  I'd like to progress the class a little further first though. 

But what does MaxAngVel do? Did you forget some code? ;-)

..I'm looking forward to your completed vehicle class. That should be very useful to a lot of people!

Oops.  I guess I should have tried my tutorial from scratch.  maxAngVel is already used in Wheels.cs in Update().  You need to delete the line float maxAngVel = 200;.  I updated the post.  

Hmm, for those wanting to make a semi-arcadey drifting game with most of it's roots in physics I may have good news.  I was looking around the code a bit and I might have a gameplan figured out.  This would let the car go past it's current slip threshold (like it does with my code changes) to a certain angle and then hold at a second threshold (unless you push it too hard) allowing for some massive high speed drifts.  

That'd be great! Just this afternoon I had added XmlParticles to the JigLibX-NetworkStateManagement concoction I have now, so I could have smoke when the car skids. However I wasn't sure where to put it... Physics like this was never my strong suit.

If you can get some pseudocode down, I can turn it into real code if you like. :-)

Physics may or may not be my strong suit.  I'm still trying to figure that out.

Huge breakthrough!  I was bumping around in Wheel.cs doing trial and error modifications of different variables so I could come up with a drifting mod when I stumbled upon the answer.  

nikescar:

Maybe you could help me with something.  I have a dust emitter that right now is centered on my car object.  I would like to have the dust originate from the rear of the car though.  I haven't really looked into matrices too much but I'm pretty sure I would have to do some kind of multiplication of the two matrices.  The dust emitter would essentially rotate around the center of the car at a certain distance while keeping at the rear of the car, following the orientation.  Not sure if that makes sense.

Yes, that makes sense. It's not that difficult at all. You want to take the rotation of the car, and move your pivot point x distance behind the car. I'm not sure if the car object uses Vector3s or matrices for rotation - I'll look at the code and post when I have it working. (I'm using the positions of the rear tires for particle effects so I hadn't needed to do this yet).

BTW, I think you had edited your post to add this in? I'm pretty sure I didn't see it the first time I read your response. It's really better to add a new post, since I had no way of knowing anything had changed and just now came back in here to look at your code again. Or I could be completely wrong and misremembering things...

Alright, here you go:


The code should be pretty self explanatory. pCar is an instance of my PlayerCar object, which is basically a wrapper for CarObject that adds high level functionality specific to my game, such as score, network data, weapons, etc. OffsetAmount is a Vector3 that is the relative offset you want, in this case 3 units behind of the center of the car. OffsetPosition is the final, global, relative position, that you can then pass into your particle system or something. It took some trial and error to get all of these working correctly, but I've tested it in several positions and it seems to work OK. And the last line tells my ParticleComponent to add a particle at the specified position and initial velocity - replace it with your own particle code to get a nice stream of particles behind your car.

Hope this helps!

Thanks that code works perfectly for the dust emitter and I only had to add a little to fit my exhaust emitter.