Which OpenGL flavor to support 2.x, 3.x or 4.x, followed by which GLSL level to support, and which GL ES flavor to support 1.x, 2.0 or 3.0 and their respective GLSL levels.
Not to mention vendor specific extensions and workarounds driver bugs.
So one ends with multiple code paths, if several versions are to be supported. Similar to how HTML or POSIX are portable, but then again not so much.
Comments
What hurts the most? I would think the imperative drawing stuff would be missed least.
Which OpenGL flavor to support 2.x, 3.x or 4.x, followed by which GLSL level to support, and which GL ES flavor to support 1.x, 2.0 or 3.0 and their respective GLSL levels.
Not to mention vendor specific extensions and workarounds driver bugs.
So one ends with multiple code paths, if several versions are to be supported. Similar to how HTML or POSIX are portable, but then again not so much.