Kepler Light Curve

turtles-own
[ 
  vx     ;; x-component of velocity vector
  xc     ;; real x-coordinate (in case particle leaves world)
  yc     ;; real y-coordinate (in case particle leaves world)
]

globals
[
  period
  flux
  max-flux
  scaler
  g  ;; Gravitational Constant
]

;;;;;;;;;;;;;;;;;;;;;;;;
;;; Setup Procedures ;;;
;;;;;;;;;;;;;;;;;;;;;;;;

to setup
  clear-all
  set scaler scale
  setup-patches
  set max-flux count patches with [pcolor = yellow]
  set-default-shape turtles "circle"
  set period 1000000
  reset-ticks
end 

to setup-patches
  ask patches[set pcolor black]
  ask patches with [(sqrt((pxcor * pxcor) + (pycor * pycor)) < 200)][set pcolor yellow]
end 


;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Runtime Procedures ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;

to go
  if ((ticks mod period) = 0)
  [
    reset-ticks
    instance-planet
  ]
  ask turtles [ update-position ]
  calculate-flux
  check-position
  tick
end 

to instance-planet
  clear-turtles
  crt 1
  [ 
    set period round (1000 / scaler * sqrt(orbit-distance * orbit-distance * orbit-distance))
    set xc -300
    set yc 0
    set color black
    set size (200 * (planet-radius / (100 - orbit-distance)))
    setxy xc yc
    set vx (sqrt ((0.593) / orbit-distance)) * scaler
  ]
    set-plot-x-range (0) (5 * period)
end 

to update-position ;; Turtle Procedure
  ;; As our system is closed, we can safely recenter the center of mass to the origin.
  set xc (xc + vx)
  adjust-position
end 

to check-position
  ask turtles[
    if xc > max-pxcor[ die ]
  ]
end 

to adjust-position ;; Turtle Procedure
  ;; If we're in the visible world (the world inside the view)
  ;; update our x and y coordinates.
  ;; if there is no patch at xc yc that means it is outside the world
  ;; and the turtle should just be hidden until it returns to the
  ;; viewable world.
  ifelse patch-at (xc - xcor) (yc - ycor) != nobody
  [ setxy xc yc
    show-turtle
  ]
  [ hide-turtle ]
end 

to calculate-flux
  ask turtles[
    ask patches in-radius (size / 2)
      [set pcolor black]
  ]
  set flux ((count patches with [pcolor = yellow]) / max-flux)
  ask turtles[
    ask patches in-radius size[
    if (sqrt((pxcor * pxcor) + (pycor * pycor)) < 200)
      [set pcolor yellow]
    ]
  ]


;  ifelse count turtles > 0[
;    ifelse abs [xc] of turtle 0 < 200
;    [set flux (1 - ((planet-size * planet-size) / (200 * 200)))]
;    [set flux 1]
;  ]
;  [set flux 1]
end 

to update-patches
  if count turtles > 0[
    ask turtles[
      let x xc
      ask patches with [(sqrt((pxcor * pxcor) + (pycor * pycor)) < 200)][
        ifelse (sqrt((pxcor - x) * (pxcor - x) + (pycor * pycor)) < [size] of turtle 0)
        [set pcolor black]
        [set pcolor yellow]
      ]
    ]
  ]
end 



; Copyright 1998 Uri Wilensky.
; See Info tab for full copyright and license.