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[FEATURE] Implement multi-monitor rendering support #58
Description
As requested multiple times by users over the past weeks, adding proper multi-monitor fullscreen support should be considered. Due to today's monitor sizes and different setups, simply stretching a single, borderless window over all displays won't be a great solution. Specifically, the maximum texture size may not be enough if a user arranges 3 4K monitors side by side for example, as many GPUs only support up to 8192×8192 pixels.
My proposal here would be the following:
- Let the user configure on which displays projectM should be rendered on, ideally remembering the display name or port if we can get this from SDL.
- Let the user decide to either stretch or clone the output to the selected displays. Cloning is nice for beamer/LED screen display with a local reference monitor.
- For stretching, add a render resolution selection. If automatic, check maximum texture size and limit the render size accordingly, then stretch as needed.
- One output window should be the main one, which will render the UI.
This will require creating several output windows sharing an OpenGL context, and rendering to an off-screen surface. Then glBlitFramebuffer() can be used to copy the required image parts to each output window, eventually scaling it up.
Activity
kblaschke commentedon Nov 27, 2023
In addition to the above, if performance allows, projectMSDL could also run multiple projectM instances, showing each on a single monitor. This would allow showing different presets, but keeping the transitions synced.
MadMartian commentedon Mar 11, 2025
I've been looking for something like this for years, ever since the Qt4 projectM visualizer broke. I could make it span all my monitors with a KWin rule. I have been without that functionality for two years now.
[-]Implement multi-monitor rendering support[/-][+][FEATURE] Implement multi-monitor rendering support[/+]kblaschke commentedon Oct 7, 2025
While this feature currently has a fairly low priority, it's a good time to ask a few things on how people would expect this to work:
Any additional input is also welcome.