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Cake day: February 6th, 2025
  • borokov@lemmy.worldtoProgramming@programming.dev•What is the difference between an API, a Library, a Package, and a Framework?
    1·
    6 days ago

    Small word about OpenGL, as it seems confusing for many peoples:

    OpenGL is a spec written by Kronos group. There is no such thing as OpenGL library, or OpenGL source code. You cannot “download” OpenGL. OpenGL is really just a buch of .txt files explaining how functions should be named and what they should do. This spec define an API.

    Then, this API can be implemented by anyone, by writing code and putting it in a library.

    GPU drivers implement this API. That means that Nvidia, AMD and Intel have their own implementation.

    To have access to this API from your program, you have to “getProcAdress” all function you want to use from GPU driver’s DLL. As this is quite painfull, libs exist, like glew, that do it for you. These libs are really just a long list of getProcAdress for all entry points.

    That’s also why you cannot “static link” with OpenGL. As function can only be retrieved at runtime.

    Another interesting things is MESA. It’s a CPU implementation of OpenGL spec. So MESA is a lib, with source code and so on. You can download it, link against it, etc… This is very useful when you want to do 3D without GPU (yes, this happen, especially in medical domain).