Point in polygon containment

turtles-own [name my_to]
globals [reset Contained imonitor x3 y3 x4 y4 thisslope check_m check_b test_x test_y test_m test_b left_x left_y hlist Ix Iy radius ExtList wholist step pos colors slopes intercepts Ax Ay Bx By Cx Cy ABx ABy ABm ABb BCx BCy BCm BCb CAx CAy CAm CAb midx midy]

to doit
  if reset = 1 [ca clear-output set reset 0]
  if count turtles with [name = "vert"] != 0 and count turtles with [name = "test"] != 0 [contain stop set reset 1]
  if count turtles with [name = "vert"] != 0 and count turtles with [name = "test"] = 0 [testpoint stop]
  if count turtles with [name = "vert"] = 0 [makepoly stop]
end 

to makepoly
  ;make color set
  ca
  clear-output
  set pos 0
  ;make points
  set hlist []
  repeat (10 + random 20) [
    set hlist lput random 360 hlist
  ]
  set hlist sort hlist
  foreach hlist [
     crt 1 [set shape "square" set size 0 set shape "dot" set color red set name "vert" set heading ? jump (3 + random 25 + (random 100) / 100)]
  ]
  set wholist []
  ask turtles[set wholist lput who wholist]
  set wholist sort wholist
  set pos -1
  repeat (length wholist - 1) [
   set pos pos + 1
   ask turtle (item pos wholist) [create-link-with turtle (item (pos + 1) wholist) set my_to item (pos + 1) wholist]]
  ask turtle (last wholist) [create-link-with turtle (first wholist) set my_to first wholist]
  ask links [set thickness 0.5 set color 5]
end 

to testpoint
  crt 1 [set shape "star" set size 2 set color 97 set name "test" setxy mouse-xcor mouse-ycor]  ;set heading random 360 jump (random 25 + (random 100) / 100)]
  set test_x [xcor] of first sort turtles with [name = "test"]
  set test_y [ycor] of first sort turtles with [name = "test"]
end 

to contain
  set left_x world-width / -2
  set left_y test_y
  crt 1 [set color black set name "left" setxy left_x left_y]
  ask turtle [who] of one-of turtles with [name = "test"][create-link-with one-of turtles with [name = "left"]]
  carefully[ask link ([who] of one-of turtles with [name = "test"]) ([who] of one-of turtles with [name = "left"]) [set thickness 0.5 set color white]][]

  set wholist []
  ask turtles with [name = "vert"][set wholist lput who wholist]
  foreach wholist [
    intersect_test ?
  ]
  ifelse (count turtles with [name = "i"] / 2) =  int (count turtles with [name = "i"] / 2) [show (se "INTERSECTIONS:" count turtles with [name = "i"] "    OUTSIDE    ")   set Contained "FALSE"][show (se "INTERSECTIONS:" count turtles with [name = "i"] "   INSIDE    ")   set Contained "TRUE"]
  set imonitor count turtles with [name = "i"]
  ask links [set thickness 0.2]
  ask links with [color = pink] [set thickness 0.5]
  set reset 1
end 

to intersect_test [w]
  set test_m 0
  set test_b test_y
  set x3 [xcor] of turtle w
  set y3 [ycor] of turtle w
  set x4 [xcor] of turtle [my_to] of turtle w
  set y4 [ycor] of turtle [my_to] of turtle w
  set check_m slope x3 y3 x4 y4
  set check_b intercept x3 y3 check_m
  carefully [
    set Ix ((check_b - test_b) / (test_m - check_m))
    set Iy (check_m * Ix + check_b)
    if Ix < test_x and (abs Ix < world-width / 2) and (abs Iy < world-height / 2) and not (y3 < test_y and y4 < test_y) and not (y3 > test_y and y4 > test_y)
    [
     crt 1 [setxy Ix Iy set shape "square" set name "i" set color blue set size 1]
     ask link w [my_to] of turtle w [set color pink]
    ]
  ][]
end 

to-report slope [x1 y1 x2 y2]
  carefully [set thisslope ((y1 - y2) / (x1 - x2))]
     [set thisslope 10000000000000]
  report thisslope
end 

to-report intercept [x y m]
  report (y - (m * x))
end