Legacy Host Application configuration

Warning

This page applies only to the legacy Windows Host Application. New installations should use the IDD. B7 is the last recommended complete stack when non-capture mouse input through the Host Application is required.

The legacy Host normally selects a compatible frame path automatically. Its persistent configuration file is:

C:\Program Files\Looking Glass (host)\looking-glass-host.ini

Use options from the same release as the Host binary. Do not copy a current Host configuration into B7 or combine a B7 Host with a current client.

Capture interface

The legacy Host captures an existing Windows display through Desktop Duplication or NvFBC. It does not use Windows Graphics Capture. Select an interface only when automatic selection fails:

[app]
capture=d12

D12

The preferred Direct3D 12 Desktop Duplication path on supported systems. It can copy directly toward shared memory and supports damage tracking.

DXGI

The Direct3D 11 Desktop Duplication compatibility path. It may require an additional staging copy and can show cursor-related capture jitter.

NvFBC

An NVIDIA SDK path available only with supported hardware and licensing. It is not required by the IDD or the normal legacy D12 path.

The exact capture-interface options can change between releases. Consult the binary’s help and the configuration comments supplied with that release.

Select an IVSHMEM device

The legacy Host selects the first IVSHMEM device by default. When the VM has more than one, os:shmDevice selects by zero-based device order:

[os]
shmDevice=1

Check the Host log after changing it; the selected device is marked with an asterisk. This option is for the legacy Host and is not an IDD helper setting.

Downsampling

The legacy Host can reduce a captured resolution before transport. Rules use source:target syntax and may match resolutions greater than a threshold:

; Downsample exactly 3840x2160 to 1920x1080
downsample=3840x2160:1920x1080

; Downsample anything larger than 1920x1080
downsample=>1920x1080:1920x1080

This saves transport bandwidth but does not reduce the guest application’s rendering work. IDD users should request the required virtual monitor resolution instead.