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HEX$ 32 Bit Values

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Samuel Gomes edited this page Nov 8, 2022 · 1 revision

LONG HEX$ values can be used to set a _PALETTECOLOR instead of using _RGB32 or _RGBA32 values.

  • Hexadecimal digits can be represented as any number or letter up to F: 0 1 2 3 4 5 6 7 8 9 A B C D E F
  • _BYTE values up to 255 can represented by two hexadecimal digits such as 1C, 23, FA, etc.
  • The HEX$ value for bright white(attribute 15) is &HFFFFFFFF or:
    • _ALPHA = FF (255), Red = FF (255), Green = FF (255), Blue = FF (255)
  • _RGB will return an alpha value of 255 for fully opaque 32 bit colors only. Values range from &HFF000000 to &HFFFFFFFF.
  • _RGB32 will return an alpha value of 255 for fully opaque colors only. Values range from &HFF000000 to &HFFFFFFFF.
  • _RGBA can set the transparency so hexadecimal values range from &H000000 (zero alpha) to &HFFFFFFFF (full alpha).
  • _RGBA32 can set the transparency so hexadecimal values range from &H000000 (zero alpha) to &HFFFFFFFF (full alpha).
  • So expanding on the principle above allows us to easily make up our own hex color values:
    • _PALETTECOLOR 1, &HFFFF0000 'COLOR 1 is full red
    • _PALETTECOLOR 2, &HFFFF00FF 'COLOR 2 is purple
    • _PALETTECOLOR 3, &HFFFFFF00 'COLOR 3 is brown

Where FF is the fully opaque _ALPHA and the 3 hex color values can range from 00 to FF (0 to 255) each.

Example(s)

Converting the color port RGB intensity palette values 0 to 63 to 32 bit hexadecimal STRING values.

SCREEN 12
DIM hex32$(15)
alpha$ = "FF"                              'solid alpha colors only
OUT &H3C8, 0: OUT &H3C9, 0: OUT &H3C9, 0: OUT &H3C9, 20 'set black background to dark blue

FOR attribute = 0 TO 15
  OUT &H3C7, attribute                     'set color attribute to read
  red$ = HEX$(INP(&H3C9) * 4)              'convert port setting to 32 bit values
  grn$ = HEX$(INP(&H3C9) * 4)
  blu$ = HEX$(INP(&H3C9) * 4)
  IF LEN(red$) = 1 THEN red$ = "0" + red$  'necessary for low or zero color intensities
  IF LEN(grn$) = 1 THEN grn$ = "0" + grn$
  IF LEN(blu$) = 1 THEN blu$ = "0" + blu$
  hex32$(attribute) = "&H" + alpha$ + red$ + grn$ + blu$
NEXT
PRINT "COLOR 0 = " + hex32$(0)
FOR i = 1 TO 15
  _PALETTECOLOR i, VAL(hex32$(i))
  COLOR i
  PRINT "COLOR" + STR$(i) + " = " + hex32$(i) 'returns closest attribute
NEXT

Code by Ted Weissgerber

Explanation: VAL is used to convert the HEX$ STRING values to valid 32 bit color values for _PALETTECOLOR.

No VAL conversion is necessary if the LONG &H hexadecimal values are entered into the program directly by the programmer.

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