SnesGT and double buffering

vanfanel · Post by **vanfanel** » Mon Mar 02, 2009 5:13 pm

Hello all!

Well, I'm using SnesGT 0.230b6 these days in my new EEE BOX (no, it's NOT a laptop: it's a nano-desktop pc focussed on low power need, with an intel ATOM processor at 1,66 Ghz), since Bsnes is just too much for this little bastard and Zsnes sound leaves a lot to be desired in the last public version.

I can run avery game at full speed with SnesGT on this eeebox, but activating vsync option causes slowdows and framerate issues now and then. Obviously it's ok, since vsync is a very cpu-intensive task, but snesGT authors have posted abot a double buffering option in their bbs:

http://gigo.retrogames.com/bbs/c-board. ... tr;tree=90

However, the emulator runs at very high speed even if I specify 60 FPS...
Have you guys configured SnesGT without tearing, running at 60FPS, without using vsync? Does that USE_FLIP = 1 option work for you??

Thanks!!

vanfanel · Post by **vanfanel** » Tue Mar 03, 2009 3:47 pm

I've also tried the "wait" option under "virtual fps", wich simulates 60FPS but without vsync (to get vsync I must activate the vsync option explicitly). Performance is just great! But tearing occurrs...and that makes the whole emulation stink.

C'mon...this post has been viewed a lot of times! No SnesGT users with double buffer out there?? It should be the most popular snes emulator right now, until Zsnes 2.0 appears...

Squall_Leonhart · Post by **Squall_Leonhart** » Tue Mar 03, 2009 8:53 pm

vsync is cpu intensive? lol wut?

kode54 · Post by **kode54** » Tue Mar 03, 2009 9:43 pm

Squall_Leonhart wrote:vsync is cpu intensive? lol wut?

Depends on whether the video drivers are crappy and poll in a loop for vsync state.

vanfanel · Post by **vanfanel** » Tue Mar 03, 2009 11:26 pm

poll in a loop? So ...what's the other option? "sleep for wait"?
There's that "sleep for wait" option in the SnesGT menu. Should that be faster?
No double/triple buffer, then?

byuu · Post by **byuu** » Tue Mar 03, 2009 11:37 pm

vanfanel wrote:poll in a loop? So ...what's the other option?

Buffer the video frame and draw it when ready, make the application think the draw was immediately successful so that emulation can continue without impediment.

And most importantly, give the option to discard frames if emulation gets way too fast, so that videoInterface->Present() is guaranteed to never lock for up to ~16ms.

vanfanel · Post by **vanfanel** » Wed Mar 04, 2009 9:34 am

thanks byuu! I hope I can use bsnes someday, in a new multicore cpu.
Meanwhile, I've to stick with snesgt...

So, if my app is running slow when using vsync, I have crappy drivers without that intelligent design you described: that's ok, but...aren't there custom drivers for GMA 950? Searched with google, but I couln't find anything...

Squall_Leonhart · Post by **Squall_Leonhart** » Wed Mar 04, 2009 11:18 am

only for linux.

vanfanel · Post by **vanfanel** » Wed Mar 04, 2009 12:41 pm

Fine; there's no snesGT for Linux, and BSnes isn't an option for ATOM processors. I'll wait for zsnes then...

Thanks!

sweener2001 · Post by **sweener2001** » Wed Mar 04, 2009 10:50 pm

did you even try the buffer options?

in the time it took for these responses, couldn't you have tried all the options you were wondering about and found out if any of them do what you want?

vanfanel · Post by **vanfanel** » Thu Mar 05, 2009 4:17 pm

#sweener

hahaha!! what kind of Retarded Squirrell (tm) do you think I am?

I asked here because the ONLY buffer option, not available in the menu but only in the INI file if you add it manually (and only according to a post in the SNES GT BBS) doesn't work for me.
Of course I've tried! I've also tried enabled the tripple buffer option in my GMA950 drivers, but damn SnesGT uses DirectDraw and we don't get too many options to configure ddraw buffers manually those days...

About the "sleep for wait" comment I made, I meant that sleep for wait didn't have any difference here, so I asked if "it was supposed to make any difference."

So, to answer your question, YES, I TRIED. WAY before posting here

Well, my english is not perfect (half Spain is retarded, so we get translated and doubed films and series here...we had a civil war and most intelligent people was killed for being in the "wrong" side, the anti-fascist one), but I try to do my best!

Deathlike2 · Post by **Deathlike2** » Thu Mar 05, 2009 5:40 pm

Are you running Vista or XP? That is relatively important in respect to DirectDraw and VSync. If you run Vista, then you are SOL (shit outta luck).

kode54 · Post by **kode54** » Thu Mar 05, 2009 9:41 pm

I could share my shitty DirectDraw timer-based vsync code again, also useful on XP systems where shitty drivers will peg the CPU (or core) at full utilization while waiting for vsync.

vanfanel · Post by **vanfanel** » Thu Mar 05, 2009 11:24 pm

I'm on XP, only because of WinUAE and SnesGT. For work I use Linux & Mac OSX in the same machine. I wouldn't be caught dead using Vista! (Well, I am only using the xp kernel: I'm not using the explorer.exe shell, and I've got only five services running: my system is fully optimizd for emulation, no need for AV shit, etc).

Sharing vsync code would be graet...if snesgt would be open source: but it is not... a real shame.

Kode54: is your avatar the final enemy of Whirlo?

Tallgeese · Post by **Tallgeese** » Fri Mar 06, 2009 12:40 am

kode54 wrote:I could share my shitty DirectDraw timer-based vsync code again, also useful on XP systems where shitty drivers will peg the CPU (or core) at full utilization while waiting for vsync.

...I wonder if that's why SMT Imagine, despite being ancient, has my Vista laptop running at 100% if fullscreened...

sweener2001 · Post by **sweener2001** » Fri Mar 06, 2009 2:32 am

vanfanel wrote:#sweener

hahaha!! what kind of Retarded Squirrell (tm) do you think I am?
I asked here because the ONLY buffer option, not available in the menu but only in the INI file if you add it manually (and only according to a post in the SNES GT BBS) doesn't work for me.
Of course I've tried! I've also tried enabled the tripple buffer option in my GMA950 drivers, but damn SnesGT uses DirectDraw and we don't get too many options to configure ddraw buffers manually those days...

About the "sleep for wait" comment I made, I meant that sleep for wait didn't have any difference here, so I asked if "it was supposed to make any difference."

So, to answer your question, YES, I TRIED. WAY before posting here
Well, my english is not perfect (half Spain is retarded, so we get translated and doubed films and series here...we had a civil war and most intelligent people was killed for being in the "wrong" side, the anti-fascist one), but I try to do my best!

someone always has to check that. if only you weren't the exception

creaothceann · Post by **creaothceann** » Fri Mar 06, 2009 9:27 am

vanfanel wrote:Well, I am only using the xp kernel: I'm not using the explorer.exe shell

What shell?

vanfanel · Post by **vanfanel** » Fri Mar 06, 2009 10:00 am

GeoShell, a minimal shell that can subst explorer.exe and take it out of my computer forever and ever.

Tallgeese · Post by **Tallgeese** » Fri Mar 06, 2009 6:50 pm

Sy kode, how do I find out if my driver is bad?

kode54 · Post by **kode54** » Fri Mar 06, 2009 9:06 pm

Try VBA or VBA-M with DirectDraw mode, note whether the CPU usage is higher with vsync enabled.

Tallgeese · Post by **Tallgeese** » Fri Mar 06, 2009 9:32 pm

Does fullscreen or windowed matter?

funkyass · Post by **funkyass** » Sat Mar 07, 2009 8:07 am

vanfanel wrote:GeoShell, a minimal shell that can subst explorer.exe and take it out of my computer forever and ever.

you can specify which program to use as the shell in the registry.

subst explore.exe is not a sane solution.

kode54 · Post by **kode54** » Sat Mar 07, 2009 8:37 am

Metatron wrote:Does fullscreen or windowed matter?

Possibly. Try windowed first.

vanfanel wrote:GeoShell, a minimal shell that can subst explorer.exe and take it out of my computer forever and ever.

Oh by the way, does that work with foobar2000's right click Open Containing Folder feature? It uses a shell API function to open the folder and hilight the track, and some replacement shells don't implement the function properly, so the function does nothing at all.

AamirM · Post by **AamirM** » Sat Mar 07, 2009 3:02 pm

kode54 wrote:I could share my shitty DirectDraw timer-based vsync code again, also useful on XP systems where shitty drivers will peg the CPU (or core) at full utilization while waiting for vsync.

Is it possible that this timer based approach may also work on Linux?

kode54 · Post by **kode54** » Sat Mar 07, 2009 10:30 pm

Only if Linux either has a function for polling vsync status without stalling, or if it can poll for the current scanline. Judging by the wine source code, there doesn't seem to be an easy answer for the latter, so I guess it's polling vsync a few times and timing the refresh rate. Although it seems that WaitForVerticalBlank is a stub too, so there's no easy way to poll vsync status either. Boo.