Re: Apple Computer, Inc made mistake to do SHR?

[Nick Westgate <nick.westgate@gmail.com>]

On Jul 14, 4:38 am, Toinet <antoine.vig...@laposte.net> wrote:
> Displaying 3,200 colors on a IIgs is really CPU consuming and would
> not let enough cycles for the program itself. That is why 3,200 colors
> images are only fixed images and are not animated.

And this relates to the root cause of the problem.

Imagine a stock Apple II(+/e/c) with 8-bit hires (280x192).
It would only be capable of 2 frames per second of animation.

The GS can do better, but suffers from a similar problem: graphics
memory must be accessed at 1MHz, so the pixel-pushing (i.e. CPU-
>graphics memory) bandwidth is severly limited. An accelerated CPU
helps, but not much. GS games often used only part of the SHR screen
for this reason.

Halving the bits/pixel means halving the needed bandwidth.

So then the question becomes: Why did Apple impose this limitation on
graphics bandwith? They certainly added some complexities in trying to
compensate (e.g. fast fill mode), so I'm guessing simplification of
Apple II compatibility was the main driver. I'm sure others can offer
more insight on this.

Cheers,
Nick.