Seriously, Josh, how many games have you played that run at 60 fps and have objects running across the screen that "not even 60fps can convey"?
Most!
I linked to the thread the other day, but actually most fast moving ones will have objects moving across the screen quickly. e.g. The objects on the side of the track. Take a fast straight away, as the objects get closer to you the faster their onscreen velocity becomes (from single digit pixels per frame to handfuls). All the inner frame information is lost. Ditto when you turn: As you approach a hairpin corner and make a tight turn (lets say a turn right). Lets say your FOV is 70 degrees and you make a 90 degree turn in .5 seconds (or 30 frames). On a 720p screen you are going to move nearly 1,650 pixels to the right. Even using an even number of frames transversed, you are looking at 55 pixels of screen advancement per frame (of course a hard turn is more jerky and going to have segments where things move slower and faster during the turn). You could compound this issue if the object in question was moving (e.g. a small S-curve where you are in the first bend and the car ahead of you is in the second bend going the opposite way).
But most frequently, in a racing game, the objects toward the edge of the screen, especially on a 16:9 aspect display, will be moving across many pixels very quickly. In FM2 I have seen objects move
inches and the
GPU is giving you none of the inner frame data. When I look at the edges objects do appear to skip, albeit quickly.
It may annoy me, not you. That is fine. Just remember that when you do a 60fps rant and someone says 30fps is sufficient! Motion Blur is just one example where games fall significantly short of mimicking cameras or the eye--but some users won't see a need for it, just as some won't see one for 60fps.
The ball is just a simplified example of a single object. The principle is much broader. How frames are rendered is very different from the eye or a camera captures information. Games capture points in time and render all the information for that singular point in time. Cameras capture all the data for a time segment (all the data for 1/60th of a second).
GPU: Point-in-time (@ 60Hz, 60 distinct points rendered at 1/60th of a second intervals)
Camera: Segment-in-time (@ 60Hz captures, all data during 1/60th time segment)
http://en.wikipedia.org/wiki/Motion_blur
Wikipedia said:
When a camera creates an image, that image does not represent a single instant of time. Because of technological constraints or artistic requirements, the image represents the scene over a period of time. As objects in a scene move, an image of that scene must represent an integration of all positions of those objects, as well as the camera's viewpoint, over the period of exposure determined by the shutter speed. In such an image, any object moving with respect to the camera will look blurred or smeared along the direction of relative motion. This smearing may occur on an object that is moving or on a static background if the camera is moving. In a film or television image, this looks natural because the human eye behaves in much the same way.
Games aren't providing all the extra information inner-frame.
This is why nAo said that the PGR4 video's weren't rendered realtime: He is spotting inner-frame motion blur that would, traditionally, be composited by taking a larger number of frames (e.g. 360) and compositing them together to 30fps. This would simulate how a camera/eye work and give much higher IQ motion blur than the vector/velocity maps most developers are using.
(accoarding to your own words) the typical eye can't notice".
You misunderstood me there (or I didn't express it right). Your eyes won't see the screen updates. At 60fps (or 70-80ish in reality--60fps is actually below the threshold from a study I read, but people don't complain because it is 30 or 60 for consoles... people should be kevetching for 72Hz... but I digress). And I agree, at 60Hz the
screen update issue is largely resolved for most gamers.
My point has been consistant about actual
object velocity and inner-frame information, which has very little to do with refresh rate (unless we start seeing displays with hundred
s of refreshes a second). Movies at 24Hz can appear smooth for the reason that, although only 24Hz, they capture all the data during a 1 second period.
A game rendered at 60Hz only captures the data at 60 points in time during a 1 second period.
Even further, blur happens automatically, like for example when rendering the road in a typical racer such as GT: The pixels of the road further in front travel less pixels but quicker (more distance) which make them come across as blured.
I don't think I am understanding. Pixels "further in front" -- do you mean like 100M+ down the road? Those do move slower, and will appear more sharp, not more blurred.
As they come closer, they are less blured and seem sharp, which further enhances the feel of speed.
As they get closer they should get blurrier because they are travelling faster and are compensating for the inner-frame information that the renderer / display haven't displayed.
UNLESS you are looking at the ground right in front of you and following a point on the ground with your eyes.
And this would be a classic example of how motion blur DOESN'T work for a game. (Thanks to Farid for pointing this out) Motion Blur would assume you are looking forward or in a specific direction in many situations. This can be a fairly safe assumption in a racing game where, when driving at high speeds, you will mostly be looking down track.
I can understand the desire for no motion blur. The arguement (that Turn10 pushed forward) that 60fps resolves the need for Motion Blur is absolute BS.
I'm not sure how many games you've played, but in all the 60 fps games I've played, what you are refering to hasn't happened. Not even in GT:HD at 1080p...
I am a PC gamer and play almost every game at 60Hz-72Hz (depending on whether the game cap/display cap comes first). On consoles I tend to favor games with stable framerates over a number. Stable 60fps>30fps; but then again I like the effect of motion blur has on making an image look "solid".
Yeah, yeah I still haven't jumped in or whatever Sony's marketing scheme is.
But don't worry about Motion Blur too much. nAo has pointed out that right now we really don't have the ability to do proper motion blur. I have seen a DX10 whitepaper that demonstrated the use of GS to do motion blur though in a more proper way, so this may be something we see in the future.
And in a way that makes us both happy.