Ruby code to help navigate the game of Iron Lung

iron_lung.rb

# Ruby code to help navigate the game of Iron Lung.

class Numeric
  def sign
    value = (self / self.abs)
    if value.nan?
      1
    else
      value
    end
  end
end

class Vector
  attr_reader :x, :y

  def self.[](x, y)
    new(x, y)
  end

  def self.north
    Vector.new(0, 1)
  end

  def initialize(x, y)
    @x, @y = x.to_f, y.to_f
  end

  def to_s
    "<#{x.to_i},#{y.to_i}>"
  end

  def angle_from_origin
    # north is 0
    north = self.class.north
    angle = (Math.acos(dot(north) / magnitude * north.magnitude) * 180 / Math::PI).round(3)
    if angle.nan?
      0.0
    else
      angle * x.sign
    end
  end

  def angle_between(other)
    (other - self).angle_from_origin
  end

  def magnitude
    Math.sqrt(x**2 + y**2)
  end

  def dot(other)
    (x * other.x) + (y * other.y)
  end

  def cross(other)
    (x * other.y) - (y * other.x)
  end

  def unit
    mag = magnitude
    Vector.new(x / mag, y / mag)
  end

  def *(scalar)
    Vector.new(x * scalar, y * scalar)
  end

  def /(scalar)
    Vector.new(x / scalar, y / scalar)
  end

  def +(other)
    Vector.new(x + other.x, y + other.y)
  end

  def -(other)
    Vector.new(x - other.x, y - other.y)
  end
end


course = [
  Vector[182, 116],

  Vector[187, 187],
  Vector[225, 200],
  Vector[322, 186],
  "PHOTO 1 @ 033",

  Vector[322, 225],
  Vector[378, 263],
  "PHOTO 2 @ 050",

  Vector[300, 325],
  Vector[259, 406],
  "PHOTO 3 @ 296",

  Vector[300, 435],
  Vector[360, 425],
  Vector[400, 325],
  Vector[560, 277],
  "PHOTO 4 @ 043",

  Vector[613, 197],
  "PHOTO 5 @ 055",

  Vector[750, 260],
  Vector[835, 280],
  Vector[864, 258],
  "PHOTO 6 @ 209",

  Vector[835, 280],
  Vector[750, 260],
  Vector[610, 310],
  Vector[560, 425],
  Vector[623, 520],
  "PHOTO 7 @ 063",

  Vector[375, 520],
  Vector[375, 625],
  Vector[250, 660],
  Vector[200, 660],
  Vector[180, 610],
  Vector[180, 576],
  "PHOTO 8 @ 184",

  Vector[180, 610],
  Vector[200, 660],
  Vector[300, 660],
  Vector[325, 741],
  "PHOTO 9 @ 018",

  Vector[475, 690],
  Vector[540, 690],
  Vector[675, 792],
  Vector[675, 828],
  "PHOTO 10 @ 295",

  Vector[675, 770],
  Vector[712, 770],
  Vector[790, 675],
]

position = course.shift
while next_thing = course.shift
  if next_thing.is_a?(Vector)
    heading = position.angle_between(next_thing)
    puts "HEAD #{(heading % 360).round(2)} until #{next_thing} (distance #{(position - next_thing).magnitude.round(2)})"
    position = next_thing
  else
    puts next_thing
    puts
  end
end

iron_lung_headings.txt

HEAD 4.03 until <187,187> (distance 71.18)
HEAD 71.11 until <225,200> (distance 40.16)
HEAD 98.21 until <322,186> (distance 98.01)
PHOTO 1 @ 033

HEAD 0.0 until <322,225> (distance 39.0)
HEAD 55.84 until <378,263> (distance 67.68)
PHOTO 2 @ 050

HEAD 308.48 until <300,325> (distance 99.64)
HEAD 333.15 until <259,406> (distance 90.79)
PHOTO 3 @ 296

HEAD 54.73 until <300,435> (distance 50.22)
HEAD 99.46 until <360,425> (distance 60.83)
HEAD 158.2 until <400,325> (distance 107.7)
HEAD 106.7 until <560,277> (distance 167.04)
PHOTO 4 @ 043

HEAD 146.48 until <613,197> (distance 95.96)
PHOTO 5 @ 055

HEAD 65.3 until <750,260> (distance 150.79)
HEAD 76.76 until <835,280> (distance 87.32)
HEAD 127.19 until <864,258> (distance 36.4)
PHOTO 6 @ 209

HEAD 307.19 until <835,280> (distance 36.4)
HEAD 256.76 until <750,260> (distance 87.32)
HEAD 289.65 until <610,310> (distance 148.66)
HEAD 336.5 until <560,425> (distance 125.4)
HEAD 33.55 until <623,520> (distance 113.99)
PHOTO 7 @ 063

HEAD 270.0 until <375,520> (distance 248.0)
HEAD 0.0 until <375,625> (distance 105.0)
HEAD 285.64 until <250,660> (distance 129.81)
HEAD 270.0 until <200,660> (distance 50.0)
HEAD 201.8 until <180,610> (distance 53.85)
HEAD 180.0 until <180,576> (distance 34.0)
PHOTO 8 @ 184

HEAD 0.0 until <180,610> (distance 34.0)
HEAD 21.8 until <200,660> (distance 53.85)
HEAD 90.0 until <300,660> (distance 100.0)
HEAD 17.15 until <325,741> (distance 84.77)
PHOTO 9 @ 018

HEAD 108.78 until <475,690> (distance 158.43)
HEAD 90.0 until <540,690> (distance 65.0)
HEAD 52.93 until <675,792> (distance 169.2)
HEAD 0.0 until <675,828> (distance 36.0)
PHOTO 10 @ 295

HEAD 180.0 until <675,770> (distance 58.0)
HEAD 90.0 until <712,770> (distance 37.0)
HEAD 140.61 until <790,675> (distance 122.92)