DRD Team

I test multiplayer on my own machine by running 2 instances of GZDoom. With ZDoom, I can place both windows side-by-side and they would both be updated in real-time regardless of which window I have focused.

With GZDoom, only the currently focused window gets updated; the other copy of the game will stay stalled and freeze until it is within focus again, making testing multiplayer on the same machine impossible...

Running both games with -noidle doesn't help.

I suspect it might be an OpenGL issue. There's nothing in the netcode that differs between ZDoom and GZDoom, as far as I know.

For example, have you tried starting one GZDoom in OpenGL, changing the ini so that it uses vid_renderer 0, starting the other GZDoom so it'll be in software, and then focus on the OpenGL window to see if the software one gets updated?