GLXpbuffer

GLXpbuffer, commonly written GLXPbuffer, is the GLX-specific handle used to identify a pbuffer, an offscreen rendering surface provided by the GLX extension for the X Window System. A pbuffer enables rendering with an OpenGL context without producing a visible window, supporting offscreen image generation, preprocessing, and testing.

Pbuffers are created with glXCreatePbuffer, which requires a Display*, a GLXFBConfig, and an attribute list that specifies properties such as width, height, color depth, and buffering options. The call returns a GLXPbuffer, an opaque handle (typically implemented as an XID) that names the pbuffer resource within the X server and GLX library.

To render to a pbuffer, it is bound to a GLX context by calling glXMakeCurrent(dpy, pbuf, ctx). Once current, subsequent OpenGL commands draw into the offscreen surface. Depending on supported extensions, the pbuffer may also be attached to a texture for render-to-texture workflows.

GLXpbuffer-based pbuffers are part of GLX legacy offscreen rendering utilities. They require GLX extension support and compatible hardware/drivers; on newer systems, framebuffer objects (FBOs) and other offscreen rendering techniques are often preferred. Nevertheless, pbuffers remain relevant for compatibility with older software and environments that rely on GLX PBuffers.