OpenTK

The Open Toolkit is set of fast, portable, low-level C# bindings for OpenGL, OpenGL ES, OpenAL, and OpenCL. It runs on all major platforms and powers hundreds of apps, games, and scientific research programs. OpenTK provides several utility libraries, including a math/linear algebra package, a windowing system, and input handling. OpenTK is not a game engine, nor does it try to be one: It offers a useful set of tools and lets you decide how to use them. It is the ideal starting point if you want to write a game or scientific application from the ground up. The OpenGL specification specifies exactly what the result/output of each function should be and how it should perform. It is then up to the developers implementing this specification to come up with a solution of how this function should operate. Since the OpenGL specification does not give us implementation details, the actual developed versions of OpenGL are allowed to have different implementations.