i finally pulled and programmed an idea i have had in my head for a long time:
how to artifact on PAL to provide extra colors (sorry guys no NTSC)...
this trick relies on the way PAL works...
what PAL does is average the color on 2 consecutive scanlines....
so what happens if we do this:
we gain a new color....
what we have to watch out for though is that the colors we combine have the same LUMA value or else it's *stipes*
today i programmed this concept in sg24 and got 28 (30 if i do something else) colors out of a coco II
the picture does NOT do it justice and i will provide a better picture later when my 40" lcd isn't being occupied by tv watchers (wife & mum)
XROAR WILL NOT SHOW THIS ! IT WILL SHOW YOU STRIPES
here is real HW (BAD PHOTO)
XROAR WILL ONLY SHOW YOU STRIPES:
the luma values that match can be gleaned from the VDG doc:
the following combinations work (alternate lines):
this can also be reversed tp provide other shades
the .asm file is here
I will try to provide a better image of the real hw doing it's thing later on