🚀 go-pugleaf

greg@zaphod.uchicago.edu (Greg Kuperberg) writes:

>In a previous article,
>Re: Jerky Animation (Was: The Correct Way to Control Game Speed),
>I discussed motion blur and a way to achieve it with sprites in a simple
>case.  I mentioned that motion blur is the best possible approximation
>for the human eye to true visual motion.  I should qualify this a little.

>If you consistently follow a motion-blurred object with your eye as it
>moves across the screen, it will not look particularly better than
>a non-blurred moving object.  The win of motion blur is when your mind
>is following the object but your eye is fixed, which is what will
>usually happen when you view an animation.

>The reason that motion-blur is right is that your eye is a
>continuously open camera; it has no oscillating shutter as movie
>projectors or high-speed cameras do.  The persistence of an image
>in your retina is about a tenth of a second, and the only way
>your mind knows that an object in your field of vision is moving is
>that its image is blurred.  Your mind de-blurs the image.  An unblurred
>moving object in an animation makes the image processing in your head
>think that the object is changing position without moving.

	Is there no other way to accomplish this? What you described in your
previous post really isnt practical for me- there will be too many objects
moving over an irregular background. My other choices have left me in a bit
of a quandry- if I use page flipping, waiting for the vertical retrace slows
things down too much, but if I dont, the animation is of course poor.

	I was wondering... is there any way to do page flipping more
efficiently than reading registers until they read the correct value?
I have recalled seeing something about being able to hook the retrace into
an interrupt- is that possible? As is, using page flipping is a ridiculous
bottle neck- here is the profile of a quickie routine I wrote to move a
sprite around the screen

page_flipping 76% of time
getting background 5%
restoring background 3%
putting sprite to screen %1 (compiled bitmap)

and the rest went to stuff like reading the joystick, etc.

Once you add more sprites, of course the page flipping takes up less of
the time, but the affect is the same- if you move the sprites at only
one pixel a frame, they look beautiful but they are WAY too slow....if you
move them more than one you get multiple images- the most I was able to
test was a speed of 10 pixels/frame and I could make out 3 distinct images!

Right now, I am looking at a couple of choices:
a) use page flipping and have a slow and boring but nice looking game...
b) dont use page flipping and have a fun game that doesnt look so hot...

I would appreciate a c) if anyone knows of one... :)

Thanks,
Chad R. Collins
collins@blkbox.com