PC Games start using motion blur

[hughJ]

"The way it plays out in my head is that you keep a decaying average of what you saw and blended in with what you see now, meaning that frames would be blurred together. "

problem is for true motion blur, the image should really be blending that of the past framebuffer(s) as well as the future ones too, otherwise you just get a trailing effect.. could probably run a game on a really poor quality LCD monitor and have the same trailing after-images for cheap

 

[ram]

There is indeed a big difference.
Motion blur make it look like you're getting a higher fps than you do.
Motion trails make it look like you're on drugs.

Ah, yes, the penny went down. I was confused 'cause of the 3dfx Q3A T-buffer demo (http://www.hardwarecentral.com/graphics/screenshots/q3_discrete_ghosts_zoom_tn.jpg). Basicly, what 3dfx showed was some sort of motion trail too (just with the difference that only 4 frames influenced the effect), and not real motion blur. For real motion blur, you would have to use the SAME weights for all rendered frames, that's simply not possible using the PS2/MotoGP framebuffer blending technique. So, for real full scene motion blur, you would need to have very high fps to get the effect good enough.

Nevertheless, IMO this "trail" effect is quite cool and should be forceable in the driver panel (that shouldn't be harder to implement than lets say OGSS).

 

[Simon F]

Just one question to the folks in the know.

Would it be possible to do temporal anti-aliasing (motion blur) by taking the rendering one frame, then blending that frame with the previous frame buffer (which you keep stored) except alpha blend it and/or shift the colour values of the previous frame so they're lighter and then store that new frame, keep on doing that over and over?

Not really. The equivalent of this approach in the spatial domain would be rendering your image at N*M resolution, putting a blur filter on it and trying to convince yourself that you've produced an antialiased result (rather than a blurred mess).

To do temporal antialiasing (in this manner) you have to super-sample in the time domain.

 

[Bambers]

BTW, Jedi Knight only seem to use the effect for the light sword, not the whole scene like MotoGP.

Its actually just a texture that trails behind the lightsabre whenever its swung.

 

[jb]

Do you have any details on that? Which technique do they use?

At this time I dont have all of the details as my version of the tools has not arrived yet. And it could be that the engine supports it and thus may not be included in UT2003. But when I was at Epic I saw one of there Demos for the GDC in which one part did use a form of Motion Blur. I remember that they had problems with the run as the resolution was set too high and UT2003 crashed. The card (GF4 but did not remember what type of GF4 it was) was running out of memory is what either Allan or Jack said. They re-ran the demo at a lower res and it worked out well. Now that might mean that they are using mulitple frames stored in the buffer to get the effect? I will ask to get the details and post them here.