glXCreatePbuffer — create an off-screen rendering area

C Specification

GLXPbuffer glXCreatePbuffer(Display * dpy,
 GLXFBConfig config,
 const int * attrib_list);



Specifies the connection to the X server.


Specifies a GLXFBConfig structure with the desired attributes for the window.


Specifies a list of attribute value pairs, which must be terminated with None or NULL. Accepted attributes are GLX_PBUFFER_WIDTH, GLX_PBUFFER_HEIGHT, GLX_PRESERVED_CONTENTS, and GLX_LARGEST_PBUFFER.


glXCreatePbuffer creates an off-screen rendering area and returns its XID. Any GLX rendering context that was created with respect to config can be used to render into this window. Use glXMakeContextCurrent to associate the rendering area with a GLX rendering context.

The accepted attributes for a GLXPbuffer are:


Specify the pixel width of the requested GLXPbuffer. The default value is 0.


Specify the pixel height of the requested GLXPbuffer. The default value is 0.


Specify to obtain the largest available pixel buffer, if the requested allocation would have failed. The width and height of the allocated pixel buffer will never exceed the specified GLX_PBUFFER_WIDTH or GLX_PBUFFER_HEIGHT, respectively. Use glXQueryDrawable to retrieve the dimensions of the allocated pixel buffer. The default value is False.


Specify if the contents of the pixel buffer should be preserved when a resource conflict occurs. If set to False, the contents of the pixel buffer may be lost at any time. If set to True, or not specified in attrib_list, then the contents of the pixel buffer will be preserved (most likely by copying the contents into main system memory from the frame buffer). In either case, the client can register (using glXSelectEvent, to receive pixel buffer clobber events that are generated when the pbuffer contents have been preserved or damaged.

GLXPbuffers contain the color and ancillary buffers specified by config. It is possible to create a pixel buffer with back buffers and to swap those buffers using glXSwapBuffers.


glXCreatePbuffer is available only if the GLX version is 1.3 or greater.

If the GLX version is 1.1 or 1.0, the GL version must be 1.0. If the GLX version is 1.2, then the GL version must be 1.1. If the GLX version is 1.3, then the GL version must be 1.2.

GLXPbuffers are allocated from frame buffer resources; applications should consider deallocating them when they are not in use.


BadAlloc is generated if there are insufficient resources to allocate the requested GLXPbuffer.

GLXBadFBConfig is generated if config is not a valid GLXFBConfig.

BadMatch is generated if config does not support rendering to pixel buffers (e.g., GLX_DRAWABLE_TYPE does not contain GLX_PBUFFER_BIT).

See Also

glXChooseFBConfig, glXCreatePbuffer, glXMakeContextCurrent, glXSelectEvent


Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see