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When I'm developing I tend to use emulation most of the time but have noticed XRoar, (running under Windows 10 64-bit), doesn't provide as smooth a framerate as VCC and MESS.

I usually test on a virtual Coco 2 to ensure I'm not dropping frames at 60Hz and in the past XRoar emulating an NTSC machine on a 60Hz LCD display has delivered silky smooth scrolling etc.

So my question is, does anyone else run XRoar under Win 10 and have you noticed the framerate being slightly `choppy', (Flagon Bird is a good game to test with)?

Is there something I need to add to xroar.conf?

I've noticed some oddities myself: strange pauses (using the GTK+ interface), far more than a frame. I'd wondered if it was something to do with my laptop... Maybe I should go back & see if it's the same with previous versions.

TBH I never expected it to be spot on, as timing is all based around the audio rate, not the frame rate - and there's bound to be some slight mismatch there that accumulates error over time leading to an occasional stutter, even emulating a 60Hz machine on a 60Hz display. But there does seem to be something else up now - just not terribly predictable!

I should probably finally get around to resampling the audio output based on the actual framerate; that might sort out a few things.

It does seem like something that's crept in, maybe in the last couple of releases, I'm not entirely sure?

I'd describe what I'm seeing as continual flicking between 60 and 30 fps, kind of how 50Hz update used to look on my 60Hz display. 60Hz update used to be pretty solid.

I'll run a comparison with older versions of XRoar and post my findings.

Had a very quick play over lunch using the scroll effect on Flagon Bird's front end running on a CoCo 2 as the test.

XRoar 0.33.1 was able to produce a smooth 60 fps scroll in sync with the game albeit not continually. Back on Windows 7 I used to click the XRoar window title bar when update became choppy to get it running smoothly again but that doesn't appear to have any effect under Windows 10. I did notice under Win 10 if I left XRoar running long enough it would eventually become smooth without my interference.

XRoar 0.34 was not able to produce a smooth 60fps scroll, at least not in an equivalent time frame to the above test.

Don't know if this helps?

Hmm, 0.34 brought SDL2 support, which I've preferred for the Windows builds, as previously it was far too dependent on users having up to date OpenGL drivers. SDL2 abstracts both OpenGL and DirectX in a uniform fashion, so more users end up with a working emulator (the giveaway was it starting with a black screen, as the sub-par OpenGL drivers on their system didn't support such basic things as textures...).

I wonder if I'm missing something in how I'm using the SDL2 API. Seems unlikely as it's so simple, but I'll give it a look at some point.

Doesn't explain my occasional pauses (actual noticeable pauses, not just choppiness) under Linux using GTK+ and GtkGLExt though!

Well, if something can be done to smooth out frame rate, that'd be great.

But don't feel you have to spend time on this though if you have bigger fish to fry. I may be the only person who's noticed.

I'm hoping the recent snapshot helps a bit.

It updates the sound just before VSYNC, like 0.33 did. Doesn't fix my problem - but then I seem to have more fundamental issues.

Cool. Looking forward to giving it a test when I finish work.

Works like a charm.

Pixel scrolling is silky smooth!

Huge thanks Ciaran.

xroar 0.34.8 crashes under Windows 10 when doing the following: 1) Full screen mode, 2) Minimize screen using ALT+TAB, 3) Clicking the xroar icon on the taskbar.