Voodoo Blur

"It's all a blur to me."

Lots of folks have been talking about the new Voodoo4 cards and their features. Hmmm, I thought the Voodoo3 cards just came out a few months ago! Anyway, here is an editorial from over at http://hoozyermama.webjump.com/ on the subject, so I thought I'd do a point counterpoint thingy on it. Enjoy!

C Point:
"....about the next wave of whiz-bang gimmicks from 3dFX. I read it, and it's a bunch of hooey. The improved anti-aliasing is a good idea, and better shadowing is nice, too. Better frame rates are always good, and 32-bit color is overdue, right? But I don't think they figure that package would sell a new $300 card, which they desperately want to do. So they throw in this depth of field crap.   And the motion blur trick. Those two were MUCH better left alone. Here's why:

About Blur effects: something moving fast on a computer or TV screen will leave a blurred trail on your retina, and in your brain. This is due to the fast, but still finite, response time of the biochemical vision apparatus. There's no need to draw a trail to make something look like it moves realistically, it just has to MOVE realistically.   Try this simple experiment at home: Turn off your mouse pointer trails, if you have them on. Now whip your pointer across the screen. Did it blur? Of course it did. The 24 fps (artificially doubled to look like 48) of motion pictures is plenty to convince your brain that you're seeing smooth, lifelike motion. Do you really think that the 50-60 fps your spanking new video card gives you, with decent game programming, is going to be less convincing than that? I will NOT pay for this "feature," given a choice, and disable it if possible if and when I encounter it.

About depth of field: When your eye is focused on any one thing, everything else in your field of vision is somewhat blurred. Focus on this word, HERE, and notice that there are plenty of other words still in your field of vision. But how many of them can you see well enough to read? So now we know that there's no need to blur things in the picture you aren't supposed to be looking at to push your attention to the one in-focus object on the screen. It's just a lazy way to make you look at the right thing, when, in a well-made game, you'd be doing that anyway. In fact, I find this effect EXTREMELY annoying. I first ran into it at an IMAX 3-D movie. It was filmed underwater, so some of the scenes had limited light available. This necessitated opening the aperture to have enough light to expose the film, which restricted the depth of field.   So I could only watch the main subject in the center of the screen, because trying to see some of the background in cool 3-D gave me a headache from the blurriness.   And, most importantly, this ruined the lifelike 3-D effect. In the real world, you can choose your point of focus, and the rest of the world gets a little fuzzy.   On your computer screen, you should also be able to choose your point of focus.   The rest of the screen will go out of focus temporarily, and your suspension of disbelief may remain intact. If the programmers decide to fuzz out everything except the thing THEY know you're supposed to be looking at, trust me, it's going to feel LESS real.   And you want me to pay extra for that, too?

Counter Point:
"While this may turn out to be true in practice, it will be hard to say until we see how game developers utilize the technology. But as someone who made films and videos for a hobby for many years, and who loves to watch films, I need to say that the effects you speak about are used constantly in computer generated films like Star Wars: Episode 1. Why would Lucasarts go out of their way to add computer-generated blur effects, and depth of field effects if they did not make the images more life-like?

If you overdo anything, you can make it annoying, but check out how they use the effect in Star Wars movies. When an X-wing or pod-racer flies past the camera into view, only the first few frames are blurred, and the blur effect fades smoothly and quickly as the X-wing or racer recedes from the camera. This greatly increases the reality of the computer generated scene by making the computer-made object react just the way a real object would react if recorded on real film.

Then take depth of field blurring, even Max Fleischer's 3-D cartoons like the real old Popeye cartoons used multiplane animation with depth of field blurring on purpose. It made the 3D effect much more real, because all real films have depth of field blurring, especially with close-ups. If used subtly, it should make 3D games seem more movie-like.

Computer-generated movement blurring and depth of field burring are advanced graphics features that I'm certain other 3D chipset makers will be incorporating into newer graphics chipsets in the future.

Finally, I'd like to point out that if you move your mouse pointer fast on the screen, it does not blur at all. Try it. Move it back and forth really fast, and focus your eyes in one spot. You will end up seeing several images of the pointer jumping around, but each momentary image is clear, not blurred. This is because the pointer is not moving smoothly from one place to another. Each image appears in one spot, and there is no blurring between positions. Movement blurring occurs on film because the shutter speed is finite, and any movement occurring during the time the shutter is open blurs the image across each frame of film. So when you watch movies, where each frame is an individual still picture, the blurring effect is on the film, not in your visual system.

Anyway, I expect that good game developers will use this technology sparingly, and effectively to make 3D games seem more like movies, and less like moving 3D-rendered images."

Dr. John