Havok Releases Free Version For PC Developers
An anonymous reader writes "Havok has released the free version of its widely-used physics and animation engine (but without source code), including tools that integrate with Autodesk 3ds Max and Maya. Developers may use Havok for free for non-commercial games, middleware, and academic projects. Here are the SDK and tools."
The point of the GPL is to produce software which is freely redistributable. But if you integrate non-Free software, then you lose the rights that the GPL is meant to protect. You can no longer share the entire project. You can no longer examine the way the entire project works. You can no longer sell the project. You can no longer fix and support the project.
If you do not want to grant others the freedom to your software that the GPL offers, then you should not license your code under the GPL and instead you should pick a more appropriate license.
In other words, it's fine to create GPL software that links with standard Windows libraries. If, however, you want to link it with libraries that are add-ons - like WinG was back in Windows 3.1 days (to pull an example off the top of my head) - you're violating the terms of the GPL.