Heat Travel Color

extensions [rnd]

globals [
  sizew
  total-shades      ; the total number of shades ( <= 100)
  midpoint-nl-color ; the named NetLogo color at the midpoint (last digit is 5)
  num-turtles
  ticks-per-round
]
patches-own [ heat  ; number in darkness range,
                    ; with 0 = white, total-shades/2 = midpoint-nl-color, total-shade = black
]

to setup
  clear-all
  random-seed 10100
  set num-turtles 2
  set ticks-per-round 5000
  set midpoint-nl-color orange
  set total-shades 100
  set sizew 60
  resize-world 0 sizew 0 sizew
  set-patch-size 10
  set-default-shape turtles "default"
  init-turtles num-turtles
  ask patches [ set heat 0 set pcolor white]
  reset-ticks
end 

to init-turtles [ n ]
   create-turtles n
  [ setxy 0 0
    ;hide-turtle
    set color yellow
    set size 3 ]
end 

to go
  ask turtles [
    set heat heat + 1
    ask patch-here [recolor-patch ]
    move-random
  ]
  tick
end 

to move-random
  right random 360 forward 1
end 

; use heat + .5 because there should be some chance of moving to a patch that was never visited

to move-weighted
  move-to rnd:weighted-one-of neighbors [ heat + .5 ]
end 

; It's faster to only recolor the patch being visited

to recolor-patch
  set pcolor make-nl-color-shade  midpoint-nl-color heat total-shades
end 

; Reports a color ranging from white to 'nl-color' to black as
;  'shade-value' ranges from 0 to 'num-shades
;
; nl-color      a NetLogo color with last digit 5: can be referenced by name
; shade-value   darkness number with 0 = white, shade-value/2 = nl-color, num-shades = black
;               numbers < 0 will be set to 0, numbers > num-shades will be set to num-shades
; num-shades    the total number of shades ( <= 100)

to-report make-nl-color-shade [ nl-color shade-value num-shades]
  ; shade-value is forced to be between 0 and num-shades
  set shade-value min list num-shades max list 0 shade-value
  report scale-color nl-color shade-value num-shades 0
end