Physics engine and other proprietary libraries

Matro · **Joined:** Sun Mar 01, 2009 1:35 am **Posts:** 1

Havok Physics for the PC is available free to projects like this. (I'm an engineer at Havok). I imagine it would be easiest on Cyan for them to just move to this version and let us download the libs direct from Havok. It'll certainly run faster than any of the alternatives and I wouldn't have to learn a new engine to contribute to the project

Cyan, any thoughts on this?

Matro

Anaerin · **Joined:** Wed Nov 08, 2006 10:20 pm **Posts:** 303

Uru: ABM was originally developed using Havok physics, but the licensing cost was too great for Uru Live, so they switched engine to the free-to-use PhysX library. That I am aware, there is no "Free" version of Havok that can be used on anything other than Windows, whereas PhysX can be used free on Windows and OSX, provided the project license doesn't attempt to impose it's license on third-party libraries (Like the GPL does).

Also, PhysX can be hardware accelerated with a PPU or an NVidia graphics card, which is something Havok doesn't do.

I have no connection to PhysX here, just saying how things are at the moment. I'm certain that, if you wanted to, you could rip out the PhysX engine and put a Havok one back in, or even throw in ODE (Which is what Myst V used), but at the end of the day, what we're getting to start with is a game with a PhysX engine built in, and unless there is a major technical reason for it, there seems little point in changing it for changing it's sake.

That's my take on it, anyways.

Gondar · **Posted:** Wed Mar 04, 2009 12:10 am

The reason they moved off of Havok is costs, but I suspect it's also cause Havok wasn't made for macs despite what was promised for years. (I suspect Blizzard using it was major incentive.. probably even part of their deal to have it cross-platform).
Now it is, so it's more a moot point.. but the biggest problem remains that unless we can actually get and recompile ages etc AND get the SDK used (to know how everything is called etc) we can't change the special used libraries and such. It took Cyan a lot of work to get ported from Havok to PhysX in the first place, so to change again would involve just as much from us and would involve changing physics info for the ages completely (hinted that they still had physics bugs in ported ages by the end of MOUL). We can't change it without source to the ages (someone noted physics info is baked into the ages directly) unless we could wrap calls even further for Cyan ages only or something.

This is probably why they used Cider.. if you fake the environment you can leave all the stuff as is. Somehow I get the impression that unless they can get us some SDK stuff, we're not gonna be modifying any of the packages except with lots of work and time..

(The solution? Cyan tells us if they can repackage the SDKs for those various libraries.. and if not, we start pushing the various companies for a special exempion to either use them non-profit as we will, or convert off to others we can modify as needed)

We'll see I guess. I don't know much about this, but then again until we see the source we're all much in the same boat.

Physics engine and other proprietary libraries

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