OpenGL (GLX)

Note: Hardware-accelerated OpenGL is still under active development and should be considered beta quality, but should be working well enough to be useful. Please report problems with specific OpenGL applications to the cygwin mailing list.

The Cygwin/X X Server supports both software OpenGL rendering (using the mesa software renderer), and hardware accelerated OpenGL rendering (using the native Windows OpenGL (WGL) interface).

The X server command line options -wgl and -nowgl turn on and off the use of the native Windows OpenGL implementation. Currently -wgl is only supported in multiwindow mode, and is on by default in that mode. -wgl has no effect if your display driver does not support hardware-accelerated OpenGL.

The creation of indirect GLX contexts is disabled by default. The +iglx option is required to allow them.

Table 3-1. Summary of OpenGL rendering options

software rendering a

hardware-accelerated rendering


(Uses GLX protocol, limited to OpenGL 1.4)

start server with +iglx -nowgl options


start server with +iglx -wgl options




start server with -wgl option

export LIBGL_USE_WGL=1 b

(local clients only)

a. The software renderer used (e.g. llvmpipe, softpipe) can be selected using the GALLIUM_DRIVER environment variable.
b. Since direct accelerated rendering is currently experimental, the LIBGL_USE_WGL environment variable is required to enable it, but that will be removed when the feature is mature, at which point it will be the default and export LIBGL_ALWAYS_SOFTWARE=1 will be required to force software rendering.

Currently the default configurations are:

If glxinfo | grep OpenGL outputs something mentioning your graphics card vendor, you have hardware-accelerated rendering. If it mentions Mesa, you have software rendering.

Please ensure you are using the latest display drivers for your graphics hardware before reporting any visual issues with WGL.

Known issues: