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New Post: Vehicle demo problems

glimberg — Fri, 27 Jun 2008 11:08:51 GMT

Hello,

I have succesfully been using the appVehicleDemo from the Bullet engine (C++). It seems that there should also be an BulletX version availible in the Dynamics/Vehicle/ folder.
Unfortunately nothing seems to be working when I convert the C++ demo into C#. The scene renders as expected, but the vehicle does not react on anything, even though I force this update every timestep:

int wheelIndex = 2;
mVehicle.ApplyEngineForce(1000.0f, wheelIndex);

wheelIndex = 3;
mVehicle.ApplyEngineForce(1000.0f, wheelIndex);

Have anyone succesfully used the vehicle components? Then I would be pleased to hear some advises on how you did it... thanks.

Regards,
Glimberg

Patch Uploaded

xexuxjy — Thu, 05 Jun 2008 20:55:57 GMT

xexuxjy has uploaded a patch.

Description:
Updated DiscreteDynamicsWorld to draw larger range of debug shapes

Patch Uploaded

xexuxjy — Thu, 05 Jun 2008 20:55:01 GMT

xexuxjy has uploaded a patch.

Description:
updated xnadebugdraw to fit in with normal render path and basiceffect settings

Patch Uploaded

xexuxjy — Thu, 05 Jun 2008 20:53:41 GMT

xexuxjy has uploaded a patch.

Description:
added simple sphere method

Patch Uploaded

xexuxjy — Thu, 05 Jun 2008 20:52:50 GMT

xexuxjy has uploaded a patch.

Description:
Port of capsule shape

NEW POST: projects still in development??

KleMiX — Tue, 06 May 2008 16:48:29 GMT

Hi,

All of the projects where I was evolved in are frozen.
But I hope that start from July I will reborn some of them.

Regards,
KleMiX

NEW POST: projects still in development??

DodongoXP — Mon, 05 May 2008 20:28:54 GMT

hi there

this has been awfully quiet since december last year no news or info in months, are the projects shown here still on development???

all the projects here looked very interesting

Cheers

NEW POST: Another newbie question.

BobStrogg — Fri, 18 Apr 2008 07:19:15 GMT

Peter - You might be seeing a bug similar to this: http://www.codeplex.com/xnadevru/Thread/View.aspx?ThreadId=23663

In the BulletX samples/demos I've done I ended up just leaving bodies in the world (terrible & lazy I know, but hoped it'd just be temporary).

NEW POST: Rotating Compound shapes

BobStrogg — Fri, 18 Apr 2008 07:05:26 GMT

FlashJackson - I'd also love to see BulletX improved and brought up to date with Bullet. In particular I'd like to see the various "Index out of range" exceptions (thrown some time after removing bodies from the world) fixed. I've heaps of ideas for BulletX-based projects but don't have enough time (or familiarity with Bullet's internals) to fix the fragile bits of the engine. If there's any way I can help you please let me know.

My main interest is in using BulletX with WPF and Silverlight. You can see some of my projects / demos at http://chriscavanagh.wordpress.com (or try direct at http://chriscavanagh.wordpress.com/2007/04/08/3d-physics-xbap/, http://chriscavanagh.wordpress.com/2008/03/06/silverlight-2-2d-physics-revisited/ among others).

NEW POST: Out of range Exception when removing Rigid Bodies

BobStrogg — Fri, 18 Apr 2008 06:57:00 GMT

Marklar - Well I tried the fix, but still no joy :( I also fixed (locally) a bug in RemoveOverlappingPairsContainingProxy where it's looping backwards through a loop but increments the counter when it removes an item:

public void RemoveOverlappingPairsContainingProxy(BroadphaseProxy proxy)
{
for (int i = _overlappingPairs.Count - 1; i >= 0; i--)
{
BroadphasePair pair = _overlappingPairsi;
if (pair.ProxyA == proxy ||
pair.ProxyB == proxy)
{
RemoveOverlappingPair(pair);
// i++;
}
}
}

(Commented line is my change). Unfortunately it still blows up :( I can mostly avoid the bug if I keep the World simple (using default CollisionDispatcher, SimpleBroadphase etc) and never remove items from the world, but obviously I don't want to do that.

Maybe we can work together to nail the other bugs? (I'm guessing we might find some comparing the original Bullet code to BulletX; we could also incessantly harass the Xnadevru guys or Erwin until they give in and fix it ;o] ).

NEW POST: Rotating Compound shapes

FlashJackson — Sun, 13 Apr 2008 06:33:20 GMT

It sounds an awful lot like the shapes are being translated and then rotated. If that happens, everything will be fine as long as the translation is zero, but will get really screwed up with compounding errors when the translation goes non-zero.

I doubt that is the problem and I am sure you already looked at it, but it just sounds familiar to me in that way.

By the way, I am going to be working on BulletX for an XNA engine I have been writing. I was actually going to do my own port as I have previous experience with Bullet and the C4 engine, but I found this one and now I plan to just debug/improve this one and bring it up to the current Bullet release. I have been going through these few posts and documentation trying to get any information about the status of the port (other than what files have been ported) and you seem to have done the most work with it. I would love to chat with you about your experience and where you see improvements.

CREATED ISSUE: Matrix.Inverse

DrDeth — Fri, 11 Apr 2008 05:05:06 GMT

Is there a reason why BulletX uses MathHelper.InverseMatrix instead of the built-in Matrix.Inverse method?

CREATED ISSUE: XCB feature request: maintain contentproj references in xcbproj files

missileControl — Mon, 07 Apr 2008 15:04:47 GMT

XCB should be capable of load not only a assest (FX, FBX, X, etc...) but it should also parse and load a Content.contentproj file. The xcbproj file should maintain a refernce to this contentproj file rather than a refernce to the assests themselves if the assets were loaded in this manner.

NEW POST: Out of range Exception when removing Rigid Bodies

Marklar — Sun, 30 Mar 2008 03:10:22 GMT

No problem Bob :)

I checked out your demos, they're very nice! Surprising what you can do in a browser now...

Did you by any chance run into any other bugs with Compound Shapes? I've been trying to get the working properly in my game and keep running into different stumbling blocks. The current problem I have relates to the rotation of Compound shapes as the result of a collision. I posted about it here: http://www.codeplex.com/xnadevru/Thread/View.aspx?ThreadId=24977 . If you have any ideas, I'd love to hear them!

Marklar

NEW POST: Rotating Compound shapes

Marklar — Sun, 30 Mar 2008 03:05:06 GMT

Hey, I'm hoping someone might have seen this bug and either found a solution or has an idea of what may be wrong :)

I currently have a table (compound shape), a floor (just a group of static Box shapes), and a ball (Sphere shape) that you can throw from the camera. The table is made up of 5 shapes, one box shape and four cylinders as the legs. The table is set up to have very high linear damping, and very low angular damping.

Its hard to describe what is happening, but when you shoot a ball at the table and cause it to rotate, the cylinders quickly become out of sync with their graphical representations.
I am drawing each cylinder with the world transform of CollisionShape.WorldTransform * ((CompoundShape)CollisionShape).GetChildTransform(i);
It seems like the world transform of the child shapes is only being modified by the WorldTransform.Translation of the Compound shape, and not the rotation.
The top of the table (the Box shape) works perfectly though. The starting translation for that child shape is Vector3(0f,1.5f,0f). I'm not positive, but it seems like as long as the child shapes are only translated along the rotation axis (in the case of this table, it rotates around the Y axis), everything works. Once you translate or rotate along one of the other two axes, everything goes out of sync.

I'm confused that the shapes world transform multiplied by the child shapes transform is NOT the world transform of the child shape. This implies to me that either the world transform or the child shape transform is not the value actually being used in the calculations. I've looked through what I thought would be the likely areas in the code, and haven't been able to find anything.

I'm sorry for the disjointed post, but I'm really at a loss here. Any help whatsoever, even ideas about where to look in the code would be much appreciated.
Marklar

NEW POST: Out of range Exception when removing Rigid Bodies

BobStrogg — Sat, 29 Mar 2008 19:37:16 GMT

Hey Marklar - Thanks for that :o) I hit the same problem a while ago for some demos I did. I'll give your 'fix' a try (don't care if it's "good" or not; I'm just glad you took the time to look into it).

FYI here are some of the demos:

http://chriscavanagh.wordpress.com/2007/05/26/minor-xbap-update/
http://chriscavanagh.wordpress.com/2008/03/06/silverlight-2-2d-physics-revisited/

NEW POST: Out of range Exception when removing Rigid Bodies

Marklar — Sun, 23 Mar 2008 16:28:42 GMT

Well, after a few weeks I think I was able to figure out what was wrong. CompoundCollisionAlgorithm does not call Dispose() for its list of CollisionAlgorithms. Dispose() removes the PersistentManifold from the Dispatchers manifold list. Without removing those, you will be trying to access objects that no longer exist inside the SimulationIslandManager.

To fix this, I made CompoundCollisionAlgorithm implement the IDisposible interface, and added the following code:

public void Dispose()
{
for (int i = 0; i < _childCollisionAlgorithms.Count; i++)
{
if(_childCollisionAlgorithmsi is IDisposable)
((IDisposable)_childCollisionAlgorithmsi).Dispose();
}
}

I'm not sure if this is the best way to resolve the issue, but it does work.

Marklar

UPDATED WIKI: Home

raxxla — Thu, 20 Mar 2008 15:31:16 GMT

News Feeds

http://www.XNADev.ru

First russian XNA game development community.

Our projects:

http://www.codeplex.com/dbm - Day Break motor (XNA 3D engine)
XNA Physics API (XPA)
Bullet for XNA Physics Library (BulletX)
XNA Scene Engine (XSE)
XNA Content Builder (XCB)
ChunkedLOD
XNA Content Engine (XCE)

News:

We are started with new project (XNA 3D engine) - (http://www.daybreak.ru english) (http://www.xnadev.ru russian)
BulletX first alpha available BulletX 2.50 Alpha
XCB released XCB 1.1 Production
XCB second release candidate is out XCB 1.0.2 Release Candidate
XCB release candidate is out XCB 1.0.1 Release Candidate
ChunkedLOD released ChunkedLOD Production
XPA second alpha is out XPA 0.1 Alpha

Tutorial:

XNA Physics API tutorial

NEW POST: interested to know about content engine

raxxla — Mon, 17 Mar 2008 11:10:17 GMT

DodongoXP wrote:
hello

im interested to know more about the xna content engine you are currently developing,

what is the status of that project and which features will it have ..

Cheers!
David Montes de oca Segovia

This content engine will be a part of our new project - "XNA 3D game engine and toolkit". More info will be avaliable soon...

NEW POST: Out of range Exception when removing Rigid Bodies

Marklar — Sun, 09 Mar 2008 21:19:48 GMT

Hello,

I've been playing around with the C# port of Bullet and have run into a problem when trying to remove certain rigid bodies. In the simulation I have a floor, table and cup. You can shoot objects from the camera (currently spheres) as a test. When objects roll over the edge of the floor, and drop more than 20 units I remove them from the simulation. This works great as far as the spheres are concerned, you can shoot them and remove them as much as you want. However, once one of the spheres collides with the cup (which is a compound shape), the next rigid body, either the sphere or the cup, to be removed causes an out of range exception in UnionFind.Find(int i). I've traced it back to SimulationIslandManager.cs and it seems to me like the IslandTag is being set incorrectly, or not changed when the objects are removed. I could be completely wrong though.

Has anyone else run into this problem and/or found a solution to it? I'm at somewhat of a loss at where this error could be occurring so any advice would be appreciated.
Thank you,
Marklar