Re: Connecting 8 720p projectors + Led Panel + Master Displa
Posted: Mon Aug 24, 2015 16:05
The problem with using multiple graphic cards, aside from the obvious performance drop, is that Desktop Window Manager can get confused over what it is we actually want to do.
In OpenGL there is no such thing as exclusive fullscreen like in DirectX, so for spanning multiple outputs in fullscreen, Resolume creates a borderless window at the resolution of the outputs you want to cover. The Windows window manager detects this and then enters a mode of fake fullscreen for that display.
When doing this for multiple cards the Desktop Window Manager seems to get confused as to whether or not it should do compositing or not. On secondary displays it has fullscreen windows, but on the primary display it hasn't, thus it's doing compositing for the primary display, which is not needed by the secondary displays.
This results in all sort of weirdness like flickering on and off, or having the second card flickering between the right output and the output of one of the other monitors. We've noticed it most on AMD cards, NVidia seems to handle it a little better. Sometimes even using a different adapter from the same port will solve it, for instance using MiniDP to DVI instead of to VGA.
Since Win 8, it's also no longer possible to turn off DWM, so multiple cards is unfortunately always going to be a bit hit and miss.
In OpenGL there is no such thing as exclusive fullscreen like in DirectX, so for spanning multiple outputs in fullscreen, Resolume creates a borderless window at the resolution of the outputs you want to cover. The Windows window manager detects this and then enters a mode of fake fullscreen for that display.
When doing this for multiple cards the Desktop Window Manager seems to get confused as to whether or not it should do compositing or not. On secondary displays it has fullscreen windows, but on the primary display it hasn't, thus it's doing compositing for the primary display, which is not needed by the secondary displays.
This results in all sort of weirdness like flickering on and off, or having the second card flickering between the right output and the output of one of the other monitors. We've noticed it most on AMD cards, NVidia seems to handle it a little better. Sometimes even using a different adapter from the same port will solve it, for instance using MiniDP to DVI instead of to VGA.
Since Win 8, it's also no longer possible to turn off DWM, so multiple cards is unfortunately always going to be a bit hit and miss.