I think the CD32 had a special chip (HP or ?) which did chunky to
planar.
So maybe Rebol runs cool on CD32...I will have to give that a spin and
see.
Thanks for the explanation,
Steve Shireman
[EMAIL PROTECTED] wrote:
>
> On Fri, Aug 25, 2000 at 08:03:16PM +0200, [EMAIL PROTECTED] wrote:
> > That's platform dependance. If REBOL/View was designed with the
> > Amiga chipset in mind, it would probably be quite different and
> > would be fast on the Amigas, but not really fast on the other
> > systems. It was instead designed with an abstact system in mind;
> > probably that was too abstract, and /View is using only a little
> > of the power of our computers.
>
> REBOL internally keeps data in 32-bit chunky format (image!
> datatype). This is efficient on pretty much every hardware
> architecture, with the exception of the somewhat obsolete planar
> bitmap format the Amiga chipset uses.
>
> Planar bitmaps were great in the late 80's when it was important
> to use as few bits as possible per pixel (fewer than 8 typically),
> in order to achieve high resolutions with little memory. Things have
> changed since then though, and today everyone is using 8, 16, 24
> or 32 bits per pixel. For that chunky formats are more efficient, in
> particular when manipulating individual pixels.
>
> What makes REBOL/View relatively slow on Amigas with the native graphics
> chipset is the necessary chunky-to-planar conversion. We are using
> optimized Assembler code for that, but it is still a bottleneck. On
> Amigas with graphics boards REBOL/View is reasonably fast (often
> faster than under Unix/X running on the same hardware).
>
> REBOL/View cannot directly use planar bitmaps for its internal
> images, not only because that would require some rewrites, but
> also because the up to 8 planes the Amiga hardware supports would
> not be sufficient to support the various effects View provides
> (blending, colorization etc.). Those effects need to operate on
> 32-bit images throughout, and quantize colors down to the
> requirements of the display hardware only as the last step. This
> makes chunky-to-planar conversion inevitable. If REBOL stored
> all internal bitmaps in 8 or fewer bits then errors would add up
> when processing effects and the resulting images would look "ugly".
>
> --
> Holger Kruse
> [EMAIL PROTECTED]
