Re: video card for IIGS

[a_specto@alcor.concordia.ca (Mitchell Spector)]

andrew.webber2@btinternet.com (Andrew Webber) wrote:

>> Video remains the same number of pixels and colors per screen as before,
>> though with the advantage of being able to display on a VGA-compatible
>> display (albeit less attractive looking in some respects, due to differences
>> between NTSC-RGB and VGA). 
>
>I am thinking of hunting one of these down, when you say the display
>is not quite right on a VGA monitor is it the colours that look odd?

    Color is fine. There are two problems as far as the translated video
goes: 1) Modern CRT displays. 2) The card's emulation.

    The first issue is not the fault of the card, it's just simple a drawback
of using a higher quality and better resolution display. When the IIgs 
was designed, the engineers took advantage and actually depended
on idiosyncracies of the AppleColor RGB to display graphics in a
certain way. 

    For example, the dithering in the 640 mode *depends* on a monitor 
with a high dot-pitch (0.37mm in this case) to give the illusion of solid
colors. If I connect the IIgs to my 15 kHz-compatible NEC MultiSync
display (0.28mm) I can clearly see alternating lines patterns in the IIgs
Finder that are meant to blend together on a less sharp display. Another
problem is scanline doubling. The display is brighter and more solid 
looking with thin black lines eliminated, but it has the side effect of
making  pixels square and chunky looking rather than fine and 
rounded. It's identical to what happens displaying 320x200 (MCGA) 
on a PC.

    As for the second issue, that is the fault of the card. There are 
several faults in fact, though I won't get too much into them. In a
nutshell the card is too slow to keep up with shadowing graphics
it reads from the GS's built-in video. Animation, especially in games
and demos, is extremely choppy and appears to skip frames. The
Ninjaforce MegaDemo is utterly appalling through a Second Sight,
so much so the KEGS32 emulator on my PC is much more faithful
for displaying the demo. In some cases the emulation just doesn't
work properly, in Rastan the scrolling background is blank (or worse,
I can't quite remember) and some modes, such as Double-Hi-Res,
cause the card to always lock-up when displayed.

>Apart from that do Games etc work ok?

    It is _usable_ enough to make use of a IIgs on a modern VGA 
display, though not faithful enough to replace the AppleColor RGB. 
Some people swear by the card for running AppleWorks or other 
productivity software, and rightfully so. Though for games and 
demos I have difficultly recommending it.

Mitchell Spector
a_specto@alcor.concordia.ca