prog8/compiler/res/prog8lib/cx16/palette.p8

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; Manipulate the Commander X16's display color palette.
; Should you want to restore the full default palette, you can call cbm.CINT()
; The first 16 colors can be restored to their default with set_default16()
palette {
%option ignore_unused
uword vera_palette_ptr
sub set_color(ubyte index, uword color) {
vera_palette_ptr = $fa00+(index as uword * 2)
cx16.vpoke(1, vera_palette_ptr, lsb(color))
vera_palette_ptr++
cx16.vpoke(1, vera_palette_ptr, msb(color))
}
sub get_color(ubyte index) -> uword {
vera_palette_ptr = $fa00+(index as uword * 2)
return mkword(cx16.vpeek(1, vera_palette_ptr+1), cx16.vpeek(1, vera_palette_ptr))
}
sub set_rgb_be(uword palette_ptr, uword num_colors) {
; 1 word per color entry, $0rgb in big endian format
vera_palette_ptr = $fa00
repeat num_colors {
cx16.vpoke(1, vera_palette_ptr+1, @(palette_ptr))
palette_ptr++
cx16.vpoke(1, vera_palette_ptr, @(palette_ptr))
palette_ptr++
vera_palette_ptr+=2
}
}
sub set_rgb(uword palette_words_ptr, uword num_colors) {
; 1 word per color entry (in little endian format as layed out in video memory, so $gb;$0r)
vera_palette_ptr = $fa00
repeat num_colors*2 {
cx16.vpoke(1, vera_palette_ptr, @(palette_words_ptr))
palette_words_ptr++
vera_palette_ptr++
}
}
sub set_rgb8(uword palette_bytes_ptr, uword num_colors) {
; 3 bytes per color entry, adjust color depth from 8 to 4 bits per channel.
vera_palette_ptr = $fa00
ubyte red
ubyte greenblue
repeat num_colors {
cx16.r1 = color8to4(palette_bytes_ptr)
palette_bytes_ptr+=3
cx16.vpoke(1, vera_palette_ptr, cx16.r1H) ; $GB
vera_palette_ptr++
cx16.vpoke(1, vera_palette_ptr, cx16.r1L) ; $0R
vera_palette_ptr++
}
}
sub color8to4(uword colorpointer) -> uword {
; accurately convert 24 bits (3 bytes) RGB color, in that order in memory, to 16 bits $GB;$0R colorvalue
cx16.r1 = colorpointer
cx16.r0 = channel8to4(@(cx16.r1)) ; (red) -> $00:0R
cx16.r0H = channel8to4(@(cx16.r1+1))<<4 ; (green) -> $G0:0R
cx16.r0H |= channel8to4(@(cx16.r1+2)) ; (blue) -> $GB:0R
return cx16.r0
}
sub channel8to4(ubyte channelvalue) -> ubyte {
; accurately convert a single 8 bit color channel value to 4 bits, see https://threadlocalmutex.com/?p=48
return msb(channelvalue * $000f + 135)
}
sub set_monochrome(uword screencolorRGB, uword drawcolorRGB) {
vera_palette_ptr = $fa00
cx16.vpoke(1, vera_palette_ptr, lsb(screencolorRGB)) ; G,B
vera_palette_ptr++
cx16.vpoke(1, vera_palette_ptr, msb(screencolorRGB)) ; R
vera_palette_ptr++
repeat 255 {
cx16.vpoke(1, vera_palette_ptr, lsb(drawcolorRGB)) ; G,B
vera_palette_ptr++
cx16.vpoke(1, vera_palette_ptr, msb(drawcolorRGB)) ; R
vera_palette_ptr++
}
}
sub set_all_black() {
set_monochrome($000, $000)
}
sub set_all_white() {
set_monochrome($fff, $fff)
}
sub set_grayscale() {
; set first 16 colors to a grayscale gradient from black to white
vera_palette_ptr = $fa00
cx16.r2L=0
repeat 16 {
cx16.vpoke(1, vera_palette_ptr, cx16.r2L)
vera_palette_ptr++
cx16.vpoke(1, vera_palette_ptr, cx16.r2L)
vera_palette_ptr++
cx16.r2L += $11
}
}
sub fade_step_multi(ubyte startindex, ubyte endindex, uword target_rgb) -> bool {
; Perform one color fade step for multiple consecutive palette entries.
; startindex = palette index of first color to fade
; endindex = palette index of last color to fade
; target_rgb = $RGB color value to fade towards
; Returns true if one or more colors were changed, false if no fade steps were done anymore.
; So you usually keep calling this until it returns false.
bool changed = false
while startindex <= endindex {
if fade_step(startindex, target_rgb)
changed=true
startindex++
if_z
break
}
return changed
}
sub fade_step_colors(ubyte startindex, ubyte endindex, uword target_colors) -> bool {
; Perform one color fade step for multiple consecutive palette entries, to different target colors.
; startindex = palette index of first color to fade
; endindex = palette index of last color to fade
; target_colors = address of uword $RGB array of colors to fade towards
; Returns true if one or more colors were changed, false if no fade steps were done anymore.
; So you usually keep calling this until it returns false.
bool changed = false
ubyte target_index = 0
while startindex <= endindex {
if fade_step(startindex, peekw(target_colors+target_index))
changed=true
target_index += 2
startindex++
if_z
break
}
return changed
}
sub fade_step(ubyte index, uword target_rgb) -> bool {
; Perform one color fade step for a single palette entry.
; index = palette index of the color to fade
; target_rgb = $RGB color value to fade towards
; Returns true if the color was changed, false if no fade step was done anymore.
; So you usually keep calling this until it returns false.
uword color = palette.get_color(index)
cx16.r0L = msb(color) ; r
cx16.r1L = lsb(color) >> 4 ; g
cx16.r2L = lsb(color) & 15 ; b
cx16.r0H = msb(target_rgb) & 15 ; r2
cx16.r1H = lsb(target_rgb) >> 4 ; g2
cx16.r2H = lsb(target_rgb) & 15 ; b2
ubyte changed
; use cmp() + status bits branches, to avoid multiple compares that could be done just once
cmp(cx16.r0L, cx16.r0H)
if_ne {
if_cc
cx16.r0L++
else
cx16.r0L--
changed++
}
cmp(cx16.r1L, cx16.r1H)
if_ne {
if_cc
cx16.r1L++
else
cx16.r1L--
changed++
}
cmp(cx16.r2L, cx16.r2H)
if_ne {
if_cc
cx16.r2L++
else
cx16.r2L--
changed++
}
palette.set_color(index, mkword(cx16.r0L, cx16.r1L<<4 | cx16.r2L))
return changed!=0
}
sub set_c64pepto() {
; set first 16 colors to the "Pepto" PAL commodore-64 palette http://www.pepto.de/projects/colorvic/
uword[] colors = [
$000, ; 0 = black
$FFF, ; 1 = white
$833, ; 2 = red
$7cc, ; 3 = cyan
$839, ; 4 = purple
$5a4, ; 5 = green
$229, ; 6 = blue
$ef7, ; 7 = yellow
$852, ; 8 = orange
$530, ; 9 = brown
$c67, ; 10 = light red
$444, ; 11 = dark grey
$777, ; 12 = medium grey
$af9, ; 13 = light green
$76e, ; 14 = light blue
$bbb ; 15 = light grey
]
set_rgb(colors, len(colors))
}
sub set_c64ntsc() {
; set first 16 colors to a NTSC commodore-64 palette
uword[] colors = [
$000, ; 0 = black
$FFF, ; 1 = white
$934, ; 2 = red
$9ff, ; 3 = cyan
$73f, ; 4 = purple
$4b1, ; 5 = green
$20c, ; 6 = blue
$ee6, ; 7 = yellow
$b53, ; 8 = orange
$830, ; 9 = brown
$f8a, ; 10 = light red
$444, ; 11 = dark grey
$999, ; 12 = medium grey
$9f9, ; 13 = light green
$36f, ; 14 = light blue
$ccc ; 15 = light grey
]
set_rgb(colors, len(colors))
}
sub set_default16() {
; set first 16 colors to the defaults on the X16
uword[] colors = [
$000, ; 0 = black
$fff, ; 1 = white
$800, ; 2 = red
$afe, ; 3 = cyan
$c4c, ; 4 = purple
$0c5, ; 5 = green
$00a, ; 6 = blue
$ee7, ; 7 = yellow
$d85, ; 8 = orange
$640, ; 9 = brown
$f77, ; 10 = light red
$333, ; 11 = dark grey
$777, ; 12 = medium grey
$af6, ; 13 = light green
$08f, ; 14 = light blue
$bbb ; 15 = light grey
]
set_rgb(colors, len(colors))
}
}