pbuffer

A pbuffer, short for pixel buffer, is an offscreen rendering target used in computer graphics to render content without displaying it on a window. In OpenGL contexts, pbuffers provide a drawable surface that can be rendered to, then either read back or used as a texture, depending on the platform and extensions. Pbuffers are typically created and managed through platform-specific APIs such as GLX on Unix/Linux with the X Window System and WGL on Windows.

Features and usage: A pbuffer can be configured with color buffers and may also include depth and stencil buffers. Some implementations support multisampling and other options. After rendering to a pbuffer, its contents can be copied to system memory or bound for use in subsequent rendering passes or texture-based operations, again depending on the available extensions. Creating a pbuffer usually involves functions like glXCreatePbuffer on GLX or wglCreatePbufferARB on WGL, and the pbuffer is typically associated with a GL rendering context, which may be shared with a windowed context to enable resource reuse.

History and status: Pbuffers emerged as an early solution for offscreen rendering in OpenGL before render-to-texture capabilities and framebuffer objects (FBOs) were standardized. With the advent of FBOs in later OpenGL revisions, pbuffers have largely fallen out of favor for new development and are considered legacy in modern graphics pipelines. They may still be encountered for compatibility reasons or in environments where FBO support is unavailable.

See also: OpenGL, framebuffer object, GLX, WGL, GLX_ARB_pbuffer, WGL_ARB_pbuffer.