[Coco] Coco3 colors

[Richard Goedeken]

Hello,

I'm a long time Coco fan and software engineer. I recently started kicking 
around the idea of writing a coco 3 side scroller game for fun.  I thought 
that I should get some hex color values for the 64-color palettes to use while 
making the graphics.  I didn't see any good documentation on the web for this, 
so I took the code from the latest mame release which generates the coco 3 
palettes and built it into a test app to dump out the values.  I thought this 
information might be useful to other people on this list, so I have uploaded 
the results to this pastebin page:

http://pastebin.com/nm9WJ6Gv

This table has hex values (00-FF) for both RGB and Composite output modes in 
R,G,B order.  I also did another little trick to generate 'closest match' 
tables as well.  I converted the RGB values to a different color space which 
is supposed to allow one to calculate a 'perceptual difference' metric using 
the euclidean distance between different colors.  I then used this to 
calculate the "closest" Composite palette color index for each RGB palette 
color, and vice versa.  This is in the last 2 columns.  For instance, you can 
see example colors at this web page:

http://www.coco3.com/community/2009/09/64-composite-coco-colors/

BTW the last column of colors is wrong in each of these images for some 
reason.  But if you look at RGB color 34, it's a sort of dark orange color. 
Then if you go to index 34 of the color table, the "RGB-match" column value is 
21.  This column gives the corresponding Composite palette index which looks 
the closest to the RGB color.  In this case, color 21 in the Composite palette 
is a similar shade but just a little bit lighter.  To my eyes it looks like 
the best match.  Correspondingly, Composite color 34 is light green with a 
hint of yellow.  The "Comp-Match" value for index 34 is 51.  If you look at 
RGB color 51, it's also a green with a hint of yellow hue.

I hope someone finds this information useful.  I can also post the code if 
anyone is interested.

Regards,
Richard