REM Jesse Gordon 3-25-2003. Updated comments on 2-10-2004
REM This program demonstrates how the formula:
REM colour = 32 + hue + ((2 - lum) * 72) + ((2 - sat) * 24)
REM can be used to calculate Hue, Luminance, Saturation into
REM an 8 bit number for screen 13 default colormap table.
REM There are 24 Hue levels (0 to 23) , 3 Saturation (0 to 2)
REM and 3 Luminance levels (0 to 2).
REM Hue is the color/wavelength
REM Saturation is the degree to which the color has color.
REM That is to say, that with a saturation of 0, you have mostly
REM a grey or white color. With a saturation of 2, the color is
REM bright and colorfull.
REM Lum is the brightness of it. If lum=0, then the color or gray
REM won't be very bright. If lum=2 then the color or gray will
REM be bright.

SCREEN 13 'Lets draw a nice chart showing all the colors:

CLS


hue = 0
FOR y = 0 TO 3
FOR x = 0 TO 5

x1 = (x * 4)
y1 = (y * 4)

sat = 0: Lum = 0
FOR yy = y1 TO (y1 + 2)
FOR xx = x1 TO (x1 + 2)

colour = 32 + hue + ((2 - Lum) * 72) + ((2 - sat) * 24)
LINE ((xx * 12), (yy * 12))-((xx * 12) + 11, (yy * 12) + 11), colour, BF


sat = sat + 1
NEXT
sat = 0
Lum = Lum + 1
NEXT


hue = hue + 1
NEXT
NEXT