The road to GPU physics acceleration on video games has been a long and not exactly rewarding journey. Even though Nvidia has been pushing its PhysX engine a great deal lately, only a handful of titles currently support it, while a majority of developers sit on the side wary of adopting proprietary technology. AMD on the other hand partnered with Intel-owned Havok to improve the way its graphics chips handle physics, but we've yet to see any significant development from that camp.
Looking to jumpstart widespread adoption of game physics -- or avoid being trumped by Nvidia -- AMD has taken a turn for the sensible route and announced its plans to support an open source physics library that can be used on any GPU, not just Radeons. Specifically, the company will be partnering with Pixelux Entertainment to expand the use of real-time physics through the open source Bullet Physics engine, OpenCL and DirectX 11.
Bullet Physics is currently the third most popular physics library after PhysX and Havok. It remains to be seen how Bullet compares to them in terms of features, but the partnership has the potential of finally bringing high level physics and simulation to the mainstream, without locking in users to a single platform. Hopefully we'll learn more about their plans and developer support in the near future.