A _header-only_ library. Not sure how LGPL works for those - not much to avoid linking against... Throw it in your own .dll / .so and use that in your closed-source projects? Standard disclosure: IANAL.
Uh, no, it's not. The shaders are clearly part of the work, so you need to make sure that the shaders are "dynamically linked"; i.e. can be replaced by the end user with their own version in order to comply with the terms of the LGPL.
A program that contains no derivative of any portion of the Library, but is designed to work with the Library by being compiled or linked with it, is called a "work that uses the Library". Such a work, in isolation, is not a derivative work of the Library, and therefore falls outside the scope of this License.
I am confused with that paragraph. So if I statically compiled a project with Qt without any modification, does it fall outside the scope of LGPL as well?
>(1) If you statically link against an LGPLed library, you must also provide your application in an object (not necessarily source) format, so that a user has the opportunity to modify the library and relink the application.
This is covered in sections 6 and 6a of the LGPL 2.1.
It is a library.