Looking Glass

Welcome to the home of Looking Glass, a KVM Frame Relay (KVMFR) implementation.

What is Looking Glass

Looking Glass is an open source application that allows the use of a KVM (Kernel-based Virtual Machine) configured for VGA PCI Pass-through without an attached physical monitor, keyboard or mouse. This is the final step required to move away from dual booting with other operating systems for legacy programs that require high performance graphics.


Looking Glass is targeted at extremely low latency use requirements on the local computer, it is not designed to stream over a network or pipe but rather through a block of shared memory. In current testing at a refresh rate of 60Hz it is possible to obtain equal or better then 16 milliseconds of latency with the guest. If the user doesn't care for VSYNC this can be further reduced to under a few milliseconds on average.


Unlike network based streaming applications, Looking Glass does not use any form of compression or color space conversion, all frames are transferred to the viewer (client application) in 32-bit RGBA without any transformations or modifications. This is possible through the use of a shared memory segment which enables extremely high throughput low latency guest to host communication.

Requirements - Host

For optimal performance the host requires a video card that supports the GL_ARB_buffer_storage extension (OpenGL 4.3 or later), but will still perform well without. Anything that supports OpenGL post 2013 should do fine.

Requirements - Guest

At this time only Windows 10 is supported with either any video card supporting DXGI Desktop Duplication or the NVIDIA Capture API (Professional cards only such as Quadro).


Looking Glass has been released under the GPL 2.0 license by Geoffrey McRae of HostFission.


Geoffrey is donating his free time to this project and as such is not being paid, if you would like to support him please become a patron.