Looking Glass Beta 4 Release Candidate 3

After many months of hard work from our team, I am pleased to announce Beta 4 Release Candidate 3 which brings with it a huge number of improvements.

If you like this project and find it useful and would like to help out you can support this project directly by using the following platforms.



  • Fixed an issue where cursor shape corruption could occur on rapid shape changes.
  • Fixed an issue with NvFBC that could cause frame tearing.
  • Adjusted the host application to print out device information earlier to aid in debugging.
  • Minor optimization to NvFBC change detection logic.
  • Don’t terminate the host if NvFBC flags protected content, instead wait until capture is available again.


  • Added coloring to the client’s terminal output for warnings/errors, etc.
  • default minimizeOnFocusLoss to off
  • Stopped the windows event code from generating false events.
  • Improved the windows event handling reducing CPU usage considerably.
  • Improved NvFBC performance by boosting the kernel thread priority as is done for DXGI.
  • Documentation improvements.


  • SDL has been deprecated and is no longer needed to build the client
  • Help overlay for EGL when the escapeKey is held
  • Allow FPS display to be toggled at runtime with escapeKey+D
  • added win:autoScreensaver which automatically disables screensaver when requested by applications in the guest
  • VM->Host DMABUF support - Kernel Module — Looking Glass B4-rc3 documentation
  • asynchronous Wayland clipboard transfers
  • Release all keys when the client loses focus and prevent stuck keys when navigating away with window manager shortcuts. The old behavior can be restored with input:releaseKeysOnFocusLoss=no
  • Wayland feature parity with X11, scaling support, and improved compatibility
  • add an option to build with libdecor (-DENABLE_LIBDECOR=ON) for showing window decoration on GNOME Wayland
  • open log from taskbar notification icon is re-added with better security
  • improve cursor interactions with overlapping windows
  • documentation is now generated using sphynx and is now available as part of the CI builds on the website.
  • Fixed issue with large clipboard transfers failing
  • DXGI is now the default capture interface, NvFBC is still available but must be selected via the host configuration file.
  • DXGI CPU usage improved with smarter sleep timing in the frame thread
  • Fix issue with parsing configuration files saved in UTF8 format (Windows)
  • Client framebuffer copy performance improvements
  • EGL fixed issue with textures getting overwritten during drawing
  • OpenGL flickering issue fixed when not using a compositor
  • Old/incorrect cursor shape on initial client connection fixed.