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libretro / flycast

Flycast is a multiplatform Sega Dreamcast emulator. NOTE: No longer actively developed, use upstream repo for libretro from now on - https://github.com/flyinghead/flycast
http://reicast.com
GNU General Public License v2.0
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Stuttering occuring with OpenGL #857

Open Immersion95 opened 4 years ago

Immersion95 commented 4 years ago

I'm on Windows 10 x64 and the framerate can't sustain 60 fps with the latest core update.

It's 57 fps here with Vsync/Hard Gpu Sync 0; it was perfectly smooth before.

Vulkan is working fine though.

flyinghead commented 4 years ago

Do you know which version was perfectly smooth?

Immersion95 commented 4 years ago

I don't know, I already had problems with 638ea78

Disabling Hard GPU Sync helps but it was working great with that option before.

My CPU : i7 4790k

I tried on the Shield TV and it's buttery smooth :p

Games tested ; MVC2+SFA3

EDIT : Disabling Threaded rendering solved the problem. I can close this issue if it's ok for you :)

flyinghead commented 4 years ago

Threaded Rendering should be on at all times so no, it's not ok :)

Immersion95 commented 4 years ago

I tried everything but OpenGL+Threaded rendering stutters a lot. Using Vulkan solved it temporarily.

You can observe it on SFA3 - Character Select Screen

flyinghead commented 4 years ago

I can confirm that the frame rate is around 57-58 fps on the SFA3 character select screen. With Hard GPU Sync on it sometimes goes down to 50 with a lot of stuttering.

However I went back in time more than a year and I don't see any significant difference in framerate or stuttering. I also tried older RA versions to no avail.

Immersion95 commented 4 years ago

I can confirm that the frame rate is around 57-58 fps on the SFA3 character select screen. With Hard GPU Sync on it sometimes goes down to 50 with a lot of stuttering.

However I went back in time more than a year and I don't see any significant difference in framerate or stuttering. I also tried older RA versions to no avail.

Unfortunately I think you are right.

Frame pacing is really bad on OpenGL, some games don't run well on Vulkan (KOF 2000-2002) so it's a shame. Vulkan isn't available in older Intel GPU :(

Frame time deviation is also huge (20-30%).

I also want to correct my test with Android, it's not great but not as bad as Windows.