' Maze formed from Truchet Tiles
' This is basically the same algorithm as the famous
' Commodore Pet '10Print' one-line maze.
' Rev 1.0.0 William M Leue 4/1/2021
option base 1

const TSIZE = 30

mode 1,16
open "debug.txt" for output as #1
cls
ncols = MM.HRES\TSIZE
nrows = MM.VRES\TSIZE
dim float h = 0.0
dim float s = 1.0
dim float v = 1.0
for row = 1 to nrows-1
 y = (row-1)*TSIZE
 for col = 1 to ncols
   x = (col-1)*TSIZE
   HSV2RGB(h, s, v, r, g, b)
   c = RGB(r, g, b)
   DrawTruchetTile x, y, rnd(), c
 next col
next row
do
 page scroll 0, 0, TSIZE, -1
 y = (nrows-2)*TSIZE
 for col = 1 to ncols
   x = (col-1)*TSIZE
   HSV2RGB(h, s, v, r, g, b)
   c = RGB(r, g, b)
   DrawTruchetTile x, y, rnd(), c
 next col
 pause 200
 h = h + 0.5
 if h > 360.0 then h = 0.0
print #1, "HSV2RGB(" + str$(h) + "," + str$(s) + "," + str$(v) + "," + str$(r) + "," + str$(g) + "," +  str$(b)
loop
end

sub DrawTruchetTile x, y, r as float, c
 local cx, cy
 if r < 0.5 then
   cx = x : cy = y + TSIZE
   arc cx, cy, TSIZE\2,, 0, 90, c
   cx = x + TSIZE : cy = y
   arc cx, cy, TSIZE\2,, 180, 270, c
 else
   cx = x: cy = y
   arc cx, cy, TSIZE\2,, 90, 180, c
   cx = x + TSIZE: cy = y + TSIZE
   arc cx, cy, TSIZE\2,, -90, 0, c
 end if
end sub

' ColorConvert.inc -- BASIC include file suitable for inclusion
' wherever color specs using RGB or HSV need to be inter-converted.
' William M Leue 1/7/2021

' Convert an RGB Color to HSV values.
' the RGB values must be in range 0..255; the S and V values will
' be in range 0..1; the H value will be in range 0..360
sub RGB2HSV r, g, b, h as float, s as float, v as float
 local float rp, cmax, cmin, delta

 rp = r/255.0 : gp = g/255.0 : bp = b/255.0
 cmax = max(rp, max(gp, bp))
 cmin = min(rp, min(gp, bp))
 delta = cmax - cmin
 if delta = 0 then
   h = 0
 else if cmax = rp then
   h = 60*(((gp-bp)/delta) MOD 6)
 else if cmax = gp then
   h = 60*(((bp-rp)/delta) + 2)
 else
   h = 60*(((rp-gp)/delta) + 4)
 end if
 if cmax = 0 then
   s = 0
 else
   s = delta/cmax
 end if
 v = cmax
end sub

' Convert an HSV value to its RGB equivalent
' The S and V values must be in range 0..1; the H value must
' be in range 0..360. The RGB values will be in range 0..255.
sub HSV2RGB h as float, s as float, v as float, r, g, b
 local float hh, f, p, q, t, x, c, i
 'local i
 c = v*s
 hh = h/60.0
 i = int(hh)
 f = hh - i
 p = v*(1-s)
 q = v*(1-s*f)
 t = v*(1-s*(1-f))
 x = c*(1.0 - hi MOD 2 - 1)
 
 select case i
   case 0
     rp = v : gp = t : bp = p
   case 1
     rp = q : gp = v : bp = p
   case 2
     rp = p : gp = v : bp = t
   case 3
     rp = p : gp = q : bp = v
   case 4
     rp = t : gp = p : bp = v
   case 5
     rp = v : gp = p : bp = q
 end select
 r = rp*255 : g = gp*255 : b = bp*255
end sub

' function to return an RGB color, given the h, s, and v
' values as input parameters. The S and V values must be
' in the range 0..1; the H value must be in the range
' 0..360. The output value will be a 24-bit RGB color.
function GetRGBColor(h as float, s as float, v as float)
 local r, g, b, c

 HSV2RGB h, s, v, r, g, b
 c = RGB(r ,g, b)
 GetRGBColor = c
end function  

' draw color swatches: the left-hand one is the original
' RGB color specified by the user. The right-hand one is
' that color first converted from RGB to HSV, and then
' back again to RGB. The two swatches will be the
' identical color.
sub ShowColors r,g,b,r2,g2,b2
 local c1, c2
 
 c1 = RGB(r,g,b)
 c2 = RGB(r2,g2,b2)
 box 200,200,100,100,1, RGB(WHITE), c1
 box 400,200,100,100,1, RGB(WHITE), c2
end sub

sub ShowPixelColors r,g,b
 local c1, x, y

 box 200,400,100,100,1, RGB(WHITE), c1
 c1 = RGB(r,g,b)
 for y = 401 to 498
   for x = 201 to 298
     pixel x, y, c1
   next x
 next y
end sub