Timing, Vsync, CPU

Started by vitalir, October 29, 2007, 14:09:03

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oNyx

>i think the effects in gladiator are due to the lense size, and fov, not the frame rate.

It's short exposure. Hence no (well, less) motion blur. The framerate is the same.

>I honestly have never seen a game that requires more than 60fps, the human eye cant even pic
>up much more than that anyway.

The human eye is asynchronous. Each "pixel" is asynchronously polled every ~7hz. Basically... the new scene is sprayed over the old. That's how real life motion blur works. The quality of the eye-generated blur depends on the source material. Infinite frames (the real world) yield better blur than 60 frames for example.

Now imagine you're doing a 180° turn in 0.5 sec. With 60fps you get 30 frames in that time... 180/30=6. So, each frame has a 6° step. A quick 180° turn is more than 2 times faster, leaving you with 12 or more degrees per frame.

>Movies genereally have a frame rate of either (PAL) 25, or (NTSC) 24.

However, movies already contain excessive amounts of motion blur (unless short exposure times are used). Just press pause and you'll see. In the cinema they usually put some extra blur on top during cam turns, because it wouldn't look smooth otherwise (it still looks a tad jerky).

Btw NTSC uses 30 (interlaced - 60 progressive). 24 is cinema.

>And of course there will ne NO CRTS in use in the very near future.

Yes. However, displays will most likely allow more hz in the future. OLEDs for example can switch a lot faster.

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Well, it's a pretty complicated topic. The perceived smoothness depends on several factors. Eg the extreme contrast levels of the usual "white rect on black background" test case usually aren't reached. With real art in place everything is magically smoother. Or things don't move fast enough to make a difference (that's why 2d is usually more than fine with 60fps). Or you can cheat like movies do with a bit of generated motion blur.

Example:

The bunny does a cell size (32px) step @ 60fps, but it looks like it does a super fluid sweep. The excessive amount of blur isn't obvious to the player, but is clearly visible in screenshots.