In computing

Computing

Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...

, a GLX visual is a set of attributes that define a mode in which OpenGL

OpenGL

OpenGL is a standard specification defining a cross-language, cross-platform API for writing applications that produce 2D and 3D computer graphics. The interface consists of over 250 different function calls which can be used to draw complex three-dimensional scenes from simple primitives. OpenGL...

 programs can write to an X

X Window System

The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...

 window with GLX

GLX

GLX provides the interface connecting OpenGL and the X Window System: it enables programs wishing to use OpenGL to do so within a window provided by the X Window System.-History:...

. A list of GLX visuals can be found with the command "glxinfo". Programs can get a GLX visual matching the desired properties with glXChooseVisual. In principle, a GLX visual is an X visual augmented with ancillary buffer information.

An error message that has puzzled many an X user is "Couldn't find matching GLX visual" (or similar) — it means that the program tried to use a GLX visual that was not available on that X server. A possible solution is to change the color depth

Color depth

In computer graphics, color depth or bit depth is the number of bits used to represent the color of a single pixel in a bitmapped image or video frame buffer. This concept is also known as bits per pixel , particularly when specified along with the number of bits used...

to something that supports the requested capabilities.