glXMakeCurrent

glXMakeCurrent is a function in the GLX API used on the X Window System to bind an OpenGL rendering context to a drawable for the calling thread. By making a context current, subsequent OpenGL commands issued by that thread render into the specified drawable (window or pixmap).

Signature: GLboolean glXMakeCurrent(Display* dpy, GLXDrawable drawable, GLXContext ctx);

It returns GL_TRUE on success and GL_FALSE on failure. If ctx is non-NULL, the specified context becomes current for the calling thread for drawing to the given drawable. If ctx is NULL, the current context for the thread is released. The drawable must be a valid GLXDrawable associated with dpy, and the context must be compatible with the drawable’s visual and the display. The call can fail if the display is not open, the context is not compatible with the drawable, or the context has not been created for that display.

Notes: glXMakeCurrent operates on a per-thread basis; different threads may have different current contexts. To detach a context, you can call glXMakeCurrent(dpy, None, NULL). After rendering, the frame is typically presented with glXSwapBuffers. For environments that support separate read and draw contexts, GLX 1.3 provides glXMakeContextCurrent to bind both read and draw contexts to a thread. Related functions include glXCreateContext, glXDestroyContext, and glXGetCurrentContext.