🚀 go-pugleaf

Quoted from <1992Dec17.134730.12855@waikato.ac.nz> by ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University):

> >What you're neglecting to mention, of course, is that those frames have to be
> >in RAM first. And not just any RAM, but "chip" RAM, of which you're only allowed
> >to have a total of 2MB, even on the newest machines (or so I'm told).

    ...

> As far as I can determine, none of the followup postings has exactly refuted
> my statement. Someone explained the capabilities of the Amiga to decompress
> frame-differenced images from fast RAM into chip RAM (interestingly, I can't

    That was explaining how animation works on the Amiga, in an
    attempt to point out that the 2000 fps figure is misleading. In
    fact, the 2000 fps example also assumes that the "animation" would
    be demo stuff, like 3D vectors or bouncing text, etc, which are
    drawn in "real time", not simple animations.

    The reason the OS guys posted that figure was to show that in a
    demo which ran at 50 fps, only a very small part of each frame was
    required to switch buffers.

    Basically what we have here is an "edge" figure of 2000 fps being
    mangled into a discussion on normal animation, which is
    inappropriate.

> recally anyone mentioning anything about decompression from disk), but no one
> has claimed that this can be done at 2000 frames per second, nor do I believe
> that it is possible.

    I mentioned decompression from disk, in the form of buffering the
    data before decompressing it. The other approach, which is done
    for some trade shows but which isn't "normal", is to read the
    data directly into display RAM from disk, for the duration of the
    animation. This requires a special disk format and custom code,
    apparently. They can do the reverse when creating the animation,
    like a VCR.

    As for a conventional animation working at 2000 fps - if you use
    the OS, then yes, you'll quickly run out of frames (unless your
    animation is a very short loop, like the spinning coin Psygnosis
    use), because you haven't got any spare time to decompress
    anything. :)

    If you do the double-buffering yourself, then you can pick an
    animation that will work quickly, like a dot moving around the
    screen... :)

    BTW, do you know what's involved in double-buffering on the Mac?

> Lawrence D'Oliveiro                       fone: +64-7-856-2889
--
*** John Bickers, TAP.                   jbickers@templar.actrix.gen.nz ***
***    "Radioactivity - It's in the air, for you and me" - Kraftwerk    ***