GSDEVICEMODE
Sets the preferred graphics device to use in the program. If set to use a graphics device that is not supported by the system, the graphics device that is actually used can be different and is reported by the GSUSEDDEVICEMODE system variable.
0 = Undetected
1 = Software (BMP mode)
2 = OpenGL (recommended for working with 2D and 3D wireframe visual styles)
3 = OpenGL ES (recommended for 3D rendering as it supports advanced visual styles and high quality transparency)
4 = Custom graphics device
Type: Integer
Saved: In the registry
Range: 0 to 4
Default: 3