GSUSEDDEVICEMODE
Displays the currently used graphics device. Although you can set the preferred device using the GSDEVICEMODE system variable, it may not be supported by your hardware. In this case GSUSEDDEVICEMODE reports a different graphics device than the one set in GSDEVICEMODE.
Type: Integer
Saved: Temporarily during the session (read-only)
Range: 0 (Undetected), 1 (Software, BMP mode), 2 (OpenGL), 3 (OpenGL ES), 4 (Custom graphics device)
Default: Varies