From: WolfWings ShadowFlight <wolfwings@lightspeed.net>
  To  : ggi-develop@eskimo.com
  Date: Mon, 6 Jul 1998 00:31:50 -0700 (PDT)

Re: kgicon difficulties |-< (and new tarballs |->)

On Sun, 5 Jul 1998, KC5TJA wrote:

>> 	They aren't foreign to *VGA*, at least not anymore - all modern
>> SVGA cards do chunky pixels.  Both memory layout have advantages and
>
>Yes, I know; however, they've been doing planar graphics for much longer
>than they've been doing chunky (in the EGA).

Heh, wrong actually. }:>
CGA: Chunky 2-bit graphics/4-bit pseudo-graphics (the infamous 160x100)
Tandy: Chunky 4-bit graphics. (160/320/640x100/200)

EGA, and the backwards-compatable video modes on the VGA are pretty much
the only planar video modes ever intended, the "Mode-X" is actually a bug
that's generally available, many cards that used fancy hardware couldn't
do it, for instance.

>> disadvantages.  Planar layouts lend themselves well to things like
>> hardware scissors, alpha channels, multiple independent overlapping
>> playfields, and in general any situation where each pixel contains more
>> information than just its color.  This lets you modify only the info you
>
>Planar display systems tend to use less hardware as well, so they cost
>less.  Furthermore, bitplanes also use less memory than chunky modes, for
>the same reasons you mention above: you can exclude information you don't
>need.

Quite true, the same blitter chip, with a tiny "wrapper" can handle any
number of bit-planes, as to it, the memory layout doesn't change, it's
just sent off to blit various strips from here and there in memory.

>>want, without having to touch the other stuff.  However, one of the main
>>drawbacks of planar layouts is that they are considerably slower when it
>>comes to rapid software pixel-setting of the whole framebuffer.

This simply isn't true if you design the conversion process properly. I
know, I've seen it done well. No, it's not a quick-and-dirty programming
job, it takes a good programmer to do it well.

Hell, I can post a whole design document on doing all sorts of planar
graphics, I've seen and done blitters that blit texture-mapped polygons on
a 16-color VGA screen before, you just can't think of single pixels at a
time, that's the trick. }:>

>Again, direct CPU intervention is the answer... :)

No, a CPU for the blitter, with maybe 4k or 8k of memory for program code 
is the real answer. }:> I mean, if someone can make a complete 3D
landscape and fire routine in 256 bytes on an x86 CPU, including the
palette, even a 2k code buffer would be large enough for all but the
fanciest games.
             _
     _     _|_  WolfWings ShadowFlight
| | | | | | | | wolfwings@lightspeed.net
| | | | | | | | "Love is a bird,
|_|_| |_|_| | |  She needs to fly...
 _           /   Let all the hurt,
 \-.______,-'    Inside of you die..." - Madonna, Frozen