Frame Skipping and Buffered Rendering Issues

[EvilKingStan]

Just tried the new frame skipping on android with pretty substantial improvements in speed across the board. A few games even got the boost they needed to be full speed. Which in some cases was a pretty substantial boost. (i.e. Half-Minute Hero from about 35 fps to between 56 and 60 fps. Is there a limit to the number of frames that the emu can skip?) The main issues I have aren't really with the frame skipping, but with buffered rendering and how it affects frame skipping. For starters, I just noticed today that if buffered rendering is turned off, it fixes the ghost-image issue in Mortal Kombat, as well as helping avoid some minor graphics issues in Half-Minute Hero. So there are graphics issue caused by it. The main problem I noticed was that in 3D games, as long as buffered rendering is on, every few seconds the screen will blink. i can't tell if this is fixed by turning buffered rendering off because without it the screen flickers at a rate that could probably cause seizures. I say 3D games because the issue wasn't apparent to me in 2D menus within 3D games, nor in fully 2D games like Final Fantasy I, The Impossible Game, or Half-Minute Hero. Instead some of the graphics kind of drag around when they're moving. It's kind of like the ghost-images in MK, but it's more like they're vibrating back and forth between their original position and where they're moving to. It's a bit hard to explain without a visual, but it happens too fast to get a screenshot that shows the problem. If need be I can try one of those screen recording apps. The problem with the 2D graphics I can confirm is fixed by turning buffered rendering off. And here's something interesting, in 2D games the screen won't start flickering when the buffered render s disabled. It's unique to 3D graphics.

[VIRGIN KLM]

There is no accurate frameskipping in that generation of consoles, it's just technicaly impossible, hence alot of stuff tend to not work correctly but you can expect things to improve a bit better. As you noticed (and was expected) you cannot skip a frame that needs to pass from the framebuffer in order to be rendered properly, it's exactly the same issue with all emulators (PCSX2, Dolphin etc.) struggle to correct as much as possible.

[Henrik]

Yes it's probably not possible to have perfect frameskipping, but it can be a lot better. I only just implemented a very first version, it's not great yet.

[EvilKingStan]

Yes it's probably not possible to have perfect frameskipping, but it can be a lot better. I only just implemented a very first version, it's not great yet.

Alright, I can appreciate that. For a first version though, it works well. Like I said in my (overly-long) post above though, the problems aren't really with frameskipping, but more with buffered rendering and how it affects frameskipping. With BR off the games run a lot smoother, and with less bugs in the graphics. I know that isn't complete either, i just felt it was worth posting about.

[ssshadow]

Yes it's probably not possible to have perfect frameskipping, but it can be a lot better. I only just implemented a very first version, it's not great yet.

Alright, I can appreciate that. For a first version though, it works well. Like I said in my (overly-long) post above though, the problems aren't really with frameskipping, but more with buffered rendering and how it affects frameskipping. With BR off the games run a lot smoother, and with less bugs in the graphics. I know that isn't complete either, i just felt it was worth posting about.

Different games respond differently I suppose, Persona 3 frameskips with no problems even with buffered rendering.

[unknown]

first I am sorry I want to ask..

what the function of frame skip? I have test it in my android and the game become lag

and why disable the buffered rendering the screen become flickering??

[EvilKingStan]

first I am sorry I want to ask..

what the function of frame skip? I have test it in my android and the game become lag

and why disable the buffered rendering the screen become flickering??

Frame skip basically just takes shortcuts in games to make it run faster. Like skipping homework problems to get done sooner. Lag would just be slowness. I believe you mean that it is choppy. That's because the emulator is skipping a lot of frames to try to reach full speed. It will become smoother as the emulator gets faster.

I don't actually know enough about buffered rendering to know why the emu flickers with it off. I'll leave that explanation to someone who knows a legitimate answer.

[VIRGIN KLM]

I'll try to make it simple. Think of the buffer like a machine that makes humbergers. Without the frameskip function, every humberger gets created, and it comes out of the machine when it's ready, sooner or later. With frameskip it says to machine that you'll have to spit out every second whatever you have ready, whether that's full, half or nothing. Here's where the problems start.

[livisor]

I'll try to make it simple. Think of the buffer like a machine that makes humbergers. Without the frameskip function, every humberger gets created, and it comes out of the machine when it's ready, sooner or later. With frameskip it says to machine that you'll have to spit out every second whatever you have ready, whether that's full, half or nothing. Here's where the problems start.

So basicly what we want is a machine that makes complete burgers every second right?How does multi threading affect frameskip capabilities?

[VIRGIN KLM]

So basicly what we want is a machine that makes complete burgers every second right?How does multi threading affect frameskip capabilities?

It brings a machine extra to do the work so it can say to do the half job and the rest completes the other. But I doubt video rendering can get sliced in 2 threads, it will possibly slice the VUs on different threads and that's all.