Reimplement old Low Latency VSync too (for lower spec machines)

[Leandro Jardim]

Some disks like one James Pond II OCS with a certain trainer in particular, doesn't work well with Lagless VSync, because it needs to be emulated cycle-exact to run perfectly, and tearing appears on the screen because my laptop can't run it fully.

Formerly my machine could run that disk with Low Latency VSync, so it was a big dissapointment when I noticed it disappeared without any apparent reason from WinUAE 4.0.0, only to give their place to the new Lagless VSync.

My hope is that Low Latency VSync will come back, since it works equally well, the difference is that it has other purpose than that of Lagless VSync, so seems there is no need to remove it yet.

Do not forget that the comparison between the two VSync's are different of comparing DirectDraw vs. Direct3D 9/11, since WinUAE will not lose any feature with it, it will only make WinUAE be a more comprehensive technology.

[Toni Wilen]

This is wrong request. Correct method is to report what goes wrong in lagless sync with 1 slice enabled. It is functionally identical to old low latency. Thats why low latency is gone. (2 slices are usually also almost same and it can be much more stable than 1). Another reason why this is wrong request is that CPU speed requirements are practically same.

btw, this is also one of the rare cases where actual video recording (from camera/phone/etc) is useful.

(remember that low latency vsync took many versions before it was usable)

[Leandro Jardim]

It is functionally identical to old low latency.

Sorry, I wasn't aware it works equal. Oops.

I tried Lagless VSync with one slice to confirm it out and it worked well.

That disk in question seems to stress my machine a little, because there are some places where the game engine drops the frame rate significantly but as there aren't any sound buffer issues, I don't think this should be a bug report.

Thanks.

[Toni Wilen]

Does 2 slices also work? (It can reduce latency noticeable compared to 1 slice)

[Leandro Jardim]

It works, and I can percept a subtle difference in speed for better.

I changed some options on my video card driver also, and got a very nice speed improvement with it too.

And sorry for the delay in responding.

[rare_j]

What options were changed in the video card driver?

[Leandro Jardim]

I disabled "application optimal mode" on the Intel HD control panel ("3D" labeled button) and enabled "disable fullscreen optimizations" on winuae.exe file properties on Windows Explorer ("compatibility" tab).

I did that because I have the feel that Windows 10 is enabling VSync on all "screens", even exclusive mode ones. For a quick test I had disabled VSync and enabled triple buffering on the WinUAE GUI and for my surprise the result was a screen with perfect scrolling and light CPU usage, at least I don't know yet if this is technically possible without VSync. (*)

(*) EDIT: Yes, I discovered that it works as a substitute for VSync. I have read in some other places before that it can replace VSync, but I never understood why it isn't used then, even with those people arguing that it increases the lag on the screen update. Now I understood.