Refacored Bullet Physics Library 2.1 released

Member
Posts: 27
Joined: 2006.07
Post: #1
You can download the source code, demos and documentation of Bullet collision detection and rigid body dynamics library at http://bullet.sf.net

Based on feedback, a lot of refactoring happened, and a starting point for GPU physics is added. When using Cmake, you can autogenerate Xcode projectfiles and create universal binaries.

Thanks,
Erwin Coumans
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Sage
Posts: 1,199
Joined: 2004.10
Post: #2
This is very interesting to me -- I'm an avid user of ODE, but I'm about to write a "2.0" of my robotics simulation environment and am considering using Bullet, since it seems more actively developed -- not to mention its performance seems much better.

Are there any tutorials or general info for people coming from ODE?
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Member
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Post: #3
TomorrowPlusX Wrote:This is very interesting to me -- I'm an avid user of ODE, but I'm about to write a "2.0" of my robotics simulation environment and am considering using Bullet, since it seems more actively developed -- not to mention its performance seems much better.

Are there any tutorials or general info for people coming from ODE?

Is your development C or C++? Right now, Bullet only offers a C++ API.
Most development is driven by feedback, so please join the Bullet forum, download the latest version (2.12 as of this posting) and try to integrate.

Biggest benefit of Bullet right now is extendible C++ code, proper convex hull collision detection support and COLLADA physics import/export. Bullet provides its own constraint solver, and it is recommended to use that one, although you can also use external solvers like 'ODE quickstep' within the Bullet framework. Bullet's solver is not fully optmized yet, but it is in the planning.

I consider an C API, very similar to ODE if there is enough request, but please check out the C++ API first.

It would be nice if you can post a link to your software on the Bullet Physics forum.

Thanks,
Erwin
http://bullet.sf.net
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Sage
Posts: 1,199
Joined: 2004.10
Post: #4
It's your run-of-the-mill robotics simulator, just a framework to make it easy-ish to prototype AI. ODE actually works pretty well, I don't have any complaints with it. I'm really just interested to see if bullet would be an improvement for me. And since ODE is bringing in some components from Bullet, well... hard to say.

Here's a couple old screenshots. I'm refactoring the app -- I'm going to keep the AI framework, and update the graphics and physics code, and probably polish the UI a bit.

[Image: PANSISim.png]

And

[Image: Wandering.png]

I'm a C++ guy -- I actually like ODE's C interface, but that's only because it's logical and well documented. I wrote a C++ abstraction on top of ODE's with an XML loader for simulations.
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Jones
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Post: #5
Very Cool looking simulation, TommorowPlusX. Smile
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Luminary
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Joined: 2002.04
Post: #6
How are you doing the toon shading Grin
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Sage
Posts: 1,199
Joined: 2004.10
Post: #7
It's a fake toon shader Rasp

I basically just cranked up the ambient lighting until there was very little differentiation between light and dark ( some, but not a lot ) and then used single-pass ( subtractive ) stencil shadows. Originally the outlines were done by drawing back-facing planes with gl_lines, but profiling I found I got better performance by re-using the silhouette determination code I wrote for shadows to draw outlines.

It's actually really cheap to draw -- I wrote this code originally against a GF4MX... on my 5200, I could probably use the backfacing triangles technique, since the 5200 is a lot faster.
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Member
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Post: #8
It looks like a fun project, can you make it publically available?

Thanks,
Erwin
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Sage
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Post: #9
It's mac-only, but I'd be happy to. It's a little hacky in parts, though, which is why I'm working on a 2.0.

Where should I post it? I guess here, since it's a mac forum...
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Member
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Post: #10
TomorrowPlusX Wrote:It's mac-only, but I'd be happy to. It's a little hacky in parts, though, which is why I'm working on a 2.0.

Where should I post it? I guess here, since it's a mac forum...

I would be more then happy to host your Mac-only demo on my physics forum. You can link to that file (without annoying advertisement).

Please mail me the demo: tp at continuousphysics.com

Thanks,
Erwin
http://bullet.sf.net

PS: You didn't check the iDevGames-forum messages and your inbox is full :-)
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Sage
Posts: 1,199
Joined: 2004.10
Post: #11
I need to check my mailbox more often. I'll sign up to the bullet library when I've got a chance and probably annoy you all with questions.

Also, I'll post my app and a bunch of demo scenarios. The problem with the app is that it's PPC only, I have no idea if it will run on a new intel mac.
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