Maidens of the Kaleidoscope

~Hakurei Shrine~ => Help Me, Eirin! => Tech Support => Topic started by: Symmetry on September 06, 2014, 07:43:06 PM

Title: Technical question about the game engine and fps
Post by: Symmetry on September 06, 2014, 07:43:06 PM
Hi all,

I'm trying to work out if and how Touhou games could benefit from newer gaming monitors with features like Ultra Low Motion Blur.

So, I'm aware that there are patches for the mainline Touhou games offering an "fps" setting, and that some here like to increase that setting to make the game faster.
However, what doesn't seem to be explictly stated anywhere is this:
 - does setting e.g. 120fps in this tool actually cause the game engine to output more frames per second (meaning people see the game as subjectively running faster because their monitors are set to 60Hz, so half the frames are being dropped)
or
- does the game keep rendering at 60fps, and but internally do frameskipping (like an emulator fast-forward button)? In this case, "120fps" is misleading and should simply be called "2x speedup"

To put it another way, if I set 120fps as is talked about here, and then ran the game on a 120Hz gaming monitor, would gameplay appear to be normal speed, only twice as smooth (the way you'd expect if it were really 120fps)? Or would it still be double-speed?



Title: Re: Technical question about the game engine and fps
Post by: Agent of the BSoD on September 07, 2014, 08:35:57 PM
I'm not sure that they would benefit from new features like ultra low motion blur. They might, but I'm not in a position to test that. Someone else may have some insight into that.

The way Touhou handles speed is from the fps. Game speed is fps dependent. If you put the game at 120fps, the game will output 120fps and will run twice as fast. The extra frames are dropped. Touhou always outputs a 60Hz signal so I don't think you'd notice anything if you bump up the fps from a 60Hz monitor compared to a 120Hz monitor. You really want to keep the games at 60fps unless you want to play the games in turbo speed.
Title: Re: Technical question about the game engine and fps
Post by: Symmetry on September 07, 2014, 09:26:10 PM
Thank you for the answer!
The extra frames are dropped.
How frustrating. Still, if the in-between frames are actually rendered, I wonder if it would be possible to patch the game to output them instead?

 
Title: Re: Technical question about the game engine and fps
Post by: Agent of the BSoD on September 07, 2014, 10:20:54 PM
Possibly. They don't seem to render but the game still handles them anyway (otherwise there would be a lot of collision detection issues).
Title: Re: Technical question about the game engine and fps
Post by: shockdude on September 10, 2014, 01:29:00 AM
I'm pretty sure Touhou doesn't keep track of in-between frames. ZUN simply engineers the hitboxes so that you can almost never move through them.
I say almost never because Drake made a video of him moving straight through a pellet bullet (under atypical conditions): http://www.youtube.com/watch?v=hYuRCMmnb4k

Shmups tend to be framerate-dependent for one reason: timing. If Touhou wasn't framerate-dependent, then fluctuating framerates would cause bullets and your character to move different distances in between frames and make it extremely difficult to make precise movements. Fighting games are also framerate-dependent for similar reasons.

edit: I can't read, disregard. Drake's video is still pretty cool, though.
I'd like to see if 120FPS Touhou could be run at 120Hz. I'd think it'd be possible with EoSD at least; that game has weird issues with monitor refresh rates and I've seen Youtube videos of ordinary people not realizing Touhou 6 is running at 75FPS.