glx

GLX stands for the OpenGL Extension to the X Window System. It is a collection of extensions defined by the Khronos Group that enables OpenGL rendering within the X Window System environment. GLX provides the mechanisms for creating OpenGL rendering contexts, binding them to X drawables (such as windows or pixmaps), and presenting rendered frames to the display.

The core concepts of GLX include GLXContext, which represents an OpenGL rendering state, and GLXFBConfig or XVisualInfo, which describe the framebuffer or visual attributes supported by the X server and the graphics driver. Applications use GLX functions to query capabilities, create a context (often with specific attributes for modern OpenGL profiles), bind the context to a drawable with glXMakeCurrent, and swap buffers with glXSwapBuffers. Additional utilities allow querying driver capabilities, sharing resources between contexts, and controlling features such as vertical synchronization.

GLX operates as part of the X11 protocol stack and relies on the X server and the graphics driver (for example, Mesa-based drivers, NVIDIA, or AMD) to implement the actual rendering. Typical workflows include selecting a suitable GLXFBConfig, creating a GLXContext (potentially with glXCreateContextAttribsARB for modern profile attributes), making the context current, issuing OpenGL commands, and swapping buffers to display the result.

In practice, GLX has been the traditional path for OpenGL on X11 systems running Linux and other Unix-like operating systems. It coexists with other graphics interfaces such as EGL, which provides a cross-platform alternative for creating contexts and surfaces, especially on Wayland or non-X11 environments. GLX remains widely supported in legacy X11 setups and in environments where direct OpenGL integration with X is desired.