No love for OgreBullet?

[N_K]

Hello all.

When I started my project, I thought that integrating CEGUI will be the hardest part, but I was wrong: getting a physics engine to work correctly is the hardest thing to do. I wanted to use Newton, but no matter what, I can't get OgreNewt to work. Then, I found BtOgre and I was happy that there's a simple wrapper for a popular physics engine. Then, I've discovered it has a serious memory leak, which, depending on the scene, could cause hundreds of megabytes to get wasted.

Then, I thought I'll give OgreBullet a try. Everyone complained that it's a nightmare to get it to compile and work, but even if I'm just a beginner, I get it to compile (including the demos) in about 20 minutes. And it works. And has no memory leaks, at least not with my current test application.

So my question is: is there a specific reason why everybody avoids using it?

[jacmoe]

No reason, except that it isn't maintained by anyone (IIRC).

My advice would be: pick one, adopt it, stick with it, make it your own.

Would have been great if those projects was at Bitbucket or Github so that people could fork and contribute, but AFAIK they're not.

[Arkiruthis]

I found BtOgre ... Then, I've discovered it has a serious memory leak, which, depending on the scene, could cause hundreds of megabytes to get wasted.

Is the author currently aware of this? (i.e., is it a known issue?)

If not, it's worth reporting as the author (nikki) is still doing commits:
http://www.ogre3d.org/forums/viewtopic. ... &start=200

[Mind Calamity]

Where exactly did you find that memory leak ? I haven't noticed anything myself.

[jacmoe]

Take a closer look at the history for the btOgre project and you'll notice that there hasn't been any development going on since it was initially committed to the Git repository.
You can fork the project, though. I recommend that you do that.

OgreBullet should also be on Bitbucket or Github, so that people can contribute to it.

[ppClarity]

In my experience, integrating any of the Bullet wrappers into my code took the same or more effort than using Bullet directly. I did cherry pick a debug renderer but everything else is just straight Bullet.

[bstone]

Exactly. And the simplest debug renderer is just a line list operation.

[N_K]

I see then, the main problem is that it's not maintained anymore.

My advice would be: pick one, adopt it, stick with it, make it your own.

As a beginner, I have no choice but to experiment and try to find a wrapper which works out of the box (and leaves no mess behind). My coding skills are limited at the moment. I have enought skills to utilize a wrapper which works, but I can't write my own, or fix a serious flaw in an existing one.

Where exactly did you find that memory leak ? I haven't noticed anything myself.

It seems the leak is somewhere around BtOgre::VertexIndexToShape. Trimeshes/collision shapes are not destroyed correctly after the conversion, and neither they are after deleting the shapes manually. It's actually a known problem, just not in this forum. There are some posts on the Bullet forum about this, and you can find reports about this in a few projects which have bug trackers and uses BtOgre.

In my experience, integrating any of the Bullet wrappers into my code took the same or more effort than using Bullet directly.

I wanted to avoid it and use Newton exactly for this reason. Bullet is a great physics engine, but it's definitely not for the inexperienced.

[mkultra333]

I just use Bullet directly. As has been said, it's doesn't seem any more complex than using a wrapper. And you eliminate a extra level of convolution and possible bugs.

[nikki]

I must confess I haven't paid much attention to BtOgre since the time I made it as a quick little utility for a game I was working on. Last year I've been in college and pretty busy with courses, and this summer I have a job. Have you looked into the memory leak much? Does it seem like it would too hard to fix?

[N_K]

For a beginner like me, yes, it would be too hard to fix the problem in BtOgre itself, but on the other hand, it can be fixed easily by doing a simple modification to the Bullet collision library (although this fix is kind of hacky, and it shouldn't be done this way).

Anyway, please don't take this whole memory leak thing as an insult, I'm thankful for your work on BtOgre, and I respect that you don't have time to maintain it anymore. I just wanted to tell the experts about this problem, hoping that someone will eventually find the leak and fix it, making this neat little interface even better.

[nikki]

Fixed in the latest commit - I'm not sure whether the best way would be to have Bullet handle this (check my post in the BtOgre topic).