[Coco] Re: Ideas for a Graphics Project, part 2

[Robert Gault]

It is much more complicated than that. First, the colors in the image 
must be counted, determined, and reduced to two sets of dithered colors. 
The colors for any pixel must be very similar in intensity on each 
screen to reduce flicker when screen swapping. There is considerable 
calculation done before the image is seen, taking 5-10 minutes if I 
remember correctly. A similar method is used by the OS-9 program viewgif 
written by Vaughn Cato.

The three screen RGB flicker method, as used in the Projector, can 
rapidly reduce colors to RGB sets. The drawback is that there is no 
possibility of matching intensity of RGB colors making up any pixel. 
Therefore flicker is quite noticeable.

Richard E. Crislip wrote:
> Hello Roger
> 
> <snip>
> 
>>Sockmaster's Hi-Color mode as in Twilight Terminal is superior to The 
>>Projector's and Projector-3's flicker modes.  Sock's Hi-Color mode is 
>>complex enough to boggle you for hours.  In fact, I never learned just
>>how  he does it even after many attempts of him explaining it to me...
>>and I am  a super fast learner.  However, it involves two screens each
>>filtered for a  different color and palette set to achieve even more
>>colors and less  flicker than what P-3 can do.
> 
> 
> Without actually talking to Sockmaster, I have deduced that what he has done
> was simular to the HAM (Hold An Modify) trick done on the Amiga which
> allowed it to display all 4095 colors of its palette. The down side of the
> Amiga HAM was artifacting anytime the screen was scrolled from the original
> position. It got pretty bad during certain instances. But it was cool just
> the same.
> 
> Regards