🚀 go-pugleaf

In article <16613@helios.TAMU.EDU> mkh6317@zeus.tamu.edu writes:
>In order for the 8*24GC card to produce dramatic aceleration the
>running application must make use of the so call G_world calls.

Depends on what you mean by 'dramatic'

>Are there ANY presently available programs which support the GC
>card?  Do we know of any forth-comming programs which will support
>the GC card?  If not, then the GC is an incredible rip-off.

Umm, how about: the menu manager in system 7, the standard controls in system 7.

There are a number of programs that use gworlds, mostly they are new high-end 
color programs, this is because most system 6 macs out there don't have gworlds
(ie all the compact macs - which is most of the market). If you are writing
a program that you want to run across the full range of macs out there you
don't want to have to burden yourself with using 2 different ways of doing
something like offscreen (if you are going to have to do it yourself you
might as well do it that way and use it on all the machines). Hopefully after 
System 7 has been out a while 7 specific applications will start using
gworlds on all macs. Also people with applications out there don't say
to themselves "gworlds, what a neat idea, I'll spend 3 months gutting
my application so it can use them" because the user (except of course
those with graphics accelerators) don't perceive a lot of benefit from
them.

I think that there are going to be 3 classes of applications that use GWorlds:

	- applications that need a temporary bitmap (for example somewhere to
	  save the bits under a pulled down menu), they probably wont usually
	  see a big speedup (pulling down menus already runs fast enough)

	- applications that use a gworld as a backing store for a window,
	  these applications will do window updates (for example when you
	  bring a window to the front or when you move an overlapping window)
	  much faster, also scrolling around in a window might be faster
	  (but remember that gworlds require lots real RAM for performance -
	  paging in the stuff isn't goingto be much of a speedup - a full
	  screen at 24-bits/pixel requires about 4MB)

	- finally there will be some applications that get much more
	  performance out of gworlds/accelerators, they are going to be
	  the ones that use them in new novell ways to overlap screen drawing
	  and image drawing to give superb graphics performance (for example
	  doubled buffered animation and video stuff) 

On then other hand there is a class of applications that can't use gworlds,
(at least not in a big way), they are the high end image manipulation packages
that need to manipulate images that are many times larger than physical memory
(for example a 24-bit 300dpi full screen image that is displayed on a 
1152x870 monitor at 72dpi requires 4MB*(300/72)*(300/72) = ~70Mb this is
also why image compression is becoming so important) the people who write
such programs do their own 'virtual memory' since they can't depend on there
being 'real' virtual memory.

I think thatthe main thing about expecting 'dramatic' acceleration from
gworlds is that they might not accelerate what you want (depends on what
the programmer used them for and of course on what exactly it is that you want)
and you might be disapointed.

BTW if you are a programmer and you want to use gworlds read the docs very
carefully, always call getpixbaseaddr before touching your pixmap directly
(this makes sure that the GC is finished with it) and always swapmmumode to
32 bit addressing before you touch it (because the pixmap may have migrated
onto the card).

I think that gworlds are important and that everyone should use them -
Apple should make them available to the low end machines even on future system
6 systems - I think that 6 months from now there will be a lot more applications
out there that do (because system 7 has now shipped and because it takes a few
years for a new technology to get adopted) and you will start to see
performance increases soon, they will probably be in a 'snapier' user interface
on the other hand you probably wont see MicroSoft using them for Word or some
such (on the other hand people like MicroSoft and Aldus could use them to make
scrolling of 24-bit pictures in text speed up a lot).

	Paul

-- 
Paul Campbell    UUCP: ..!mtxinu!taniwha!paul     AppleLink: CAMPBELL.P

My son is now 2 months old, in that time he has doubled his weight,
if he does this every 2 months for the next year he will weigh over 300lbs.