Make game playable on HiDPI displays through adjustable render resolution

[Illiou]

Since as of now it's still impossible to change the resolution in any meaningful way, the game is unfortunately not playable on HiDPI laptops like my Dell XPS 13 (which means I won't be able to play the game until next year while I don't have access to my desktop computer).

• Whereas in 1920x1080 the game runs at 60 fps all the time, even with high resolution sprites, the fps drop to around 20 fps with lowest graphic settings at 3200x1800, and lower when a lot is happening on the screen.
• Changing the system resolution every time you play the game is not an option, not just because it's annoying and resizes all the windows but because it fucks up parts of the Windows interface, which is only fixed after restarting/"relogin".
• Some time ago an option "Render in native screen resolution" was introduced, but for whatever reason only for MacOS users, so this doesn't help.

Since the game seems to run in borderless fullscreen and changing the screen resolution does not seem feasible, implementing an option that changes only in game render resolution seems like the best and only solution to me.
In other words, the interface would stay at native resolution but the in game content would be rendered at a resolution specified by e.g. a slider in the options menu. This would enable all systems to make the best use of their available resolution and processing power.

If the relevant developer reads this maybe they can say a bit about whether this is feasible.

[Zavian]

I suspect that your gpu is struggling to cope with rendering at 3200x1800. I suggest posting the info requested in viewtopic.php?f=7&t=68653 , that way we and the devs can get a better idea what hardware you are using, and where the actual bottleneck is.

[Illiou]

Yes, the bottleneck is the GPU. I monitored the load on the CPU and GPU: the CPU is mostly in the range of 50%-80% load, whereas the GPU is at 100% at resolution 3200x1800 and at around 80% at 1920x1080.
I don't have time at the moment to do more testing and log saving but I will do at some point in the future. Though I'd say they won't change the general conclusion for the issue stated, since no specific performance optimization is likely allow all HiDPI computers to run the game fluently. It's just too many pixels that need to be calculated for some graphics cards.

[Loewchen]

Moved to Ideas and Suggestions.

[Koub]

the CPU is mostly in the range of 50%-80% load

Even that is impressive and surprising, knowing how Factorio is mostly monothreaded.