Running without focus

[KerBlammo!]

So back in the earlier versions of KSP I used to open the executable and then just tab away to do other things while the game loaded. Load times have significantly increased with version number and of course are much worse with mods, so it's a really handy thing to be able to do. Similarly, while making any kind of painfully long manoeuvres when I couldn't time accelerate (like in low orbits) I used to just tab away from the game for a while and it would run in the background. I know this changed quite a while back, but I was wondering if there was anyway to force this behaviour back into the game. I thought the option to "simulate in background" might do it, but that obviously pertains to something else. Any info on this (how I can get the functionality back, what the reason for the change was, etc) would be appreciated, thanks

[vexx32]

There's no way to actually disable this feature. You can, however, work around it -- it only does this when the game loses focus, which can only happen in native fullscreen mode. So, you have the option of just running it in windowed mode if you want... but you can leave it in fullscreen and use the -popupwindow command to make it run in full-window mode.

This option is available in the KSP Launcher (if you use the Launcher) under the Advanced settings; I believe it's called Fake full-screen mode.

If you use the Steam version, you can add the -popupwindow flag as a launch option (right click KSP in the Steam Library, select Properties, then click Set Launch Options and type the flag into the textbox that appears).

[KerBlammo!]

it only does this when the game loses focus, which can only happen in native fullscreen mode.

I don't understand that statement - If you click in any other window while KSP is in its own window, that still shifts focus away, whether KSP is windowed or not. Do you mean that, say I load up a YouTube clip or article, I can then click in the KSP window to give it focus and still see what I've loaded into another window (If I've resized both windows to be half the screen width, for example) or do you mean that in windowed mode, losing focus will not cause the game to stop running?

Thanks for the info on running windowed, either way.

[vexx32]

Oh, aye, I know what you mean. Yes, this 'stop running when focus is lost' behaviour does not (at least, as far as I am aware; I'm sure I'd hear about it otherwise) manifest at all in windowed modes (incl. the fake fullscreen mode). Something about how the OS, graphics card drivers, and Unity interact... Not too sure.

Something is a little weird with how Unity and/or Windows itself (and possibly other OSs, I'm not totally sure) handle fullscreen mode applications. When they're not in-focus, attempting to load graphical assets (and just generally do any actual processing) can quite frequently lead to very odd issues.

I'm not totally sure of all the technical details myself, but I know for a fact that in the past, simply alt-tabbing out of the game (or any other method of shifting focus away from KSP) when it's in true fullscreen mode has been the cause of any number of really odd glitches. Most were simple texture glitches that disappear on a game restart, but every now and again something more troubling would turn up.

To my knowledge, these oddities are not Unity-specific, but I could be wrong. More than a few fullscreen applications (especially those that are primarily designed as full-screen applications) tend to do much what KSP currently does when they lose focus; they stop processing. The Assassin's Creed titles are some that spring immediately to mind. I'm not even sure if they have a natively supported windowed mode, too.

Suffice to say, something weird happens, and I'm not fully sure where the faulty code is. I suspect it's partially OS, partially Unity (at least where KSP is concerned), but I don't know enough about either to give a comprehensive answer.

[KerBlammo!]

Thanks for the info. What I find odd is that I USED to be able to alt+tab out of (proper) full screen while the game kept running, sometimes for many hours, without any undue effects. I don't think I care enough to go back to my old versions to see which one was the last version to allow it. Maybe it changed when Unity was updated. Shame to lose the functionality, though, especially at load up. I've actually had very little trouble alt+tabbing away from other true full-screen games. Maybe just luck of the draw.