eyetest.rb

require 'rubygems'
require 'glapp'

require 'text_draw'

class EyeTest
  include GLApp

  class Chooser
    ALPHABET = ('A'..'Z').to_a + [' ']
    
    def initialize
      @choices = []
    end

    def pop
      @choices.pop
    end

    def done?
      current_characters.size == 1
    end

    def choice
      raise "not done choosing" unless done?
      current_characters.first
    end

    def choices
      split_in_two(current_characters)
    end

    def has_choices?
      !@choices.empty?
    end

    def choose(left_or_right)
      @choices << left_or_right
    end

    private

    def split_in_two(characters)
      characters.partition { |c| characters.index(c) < characters.size / 2 }
    end

    def current_characters
      @choices.inject(ALPHABET) do |chars, choice|
        left, right = split_in_two(chars)
        case choice
        when :left
          left
        when :right
          right
        end
      end
    end
  end

  def setup
    @message = []
    @chooser = Chooser.new
  end

  def update(s)
    if @chooser.done?
      @message << @chooser.choice
      @chooser = Chooser.new
    end
  end

  def setup_context
    glClearColor(0.0, 0.0, 0.0, 0.5)
    glEnable(GL_BLEND)
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
  end

  def pre_draw
    glClear(GL_COLOR_BUFFER_BIT)
  end

  def draw
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity
    glOrtho(0, 200,
            0, 200,
            -100, 100)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity
    glEnable(GL_LINE_SMOOTH)
    glEnable(GL_POINT_SMOOTH)
    glDepthMask(GL_FALSE)
    glLineWidth(2.0)
    glPointSize(3.0)

    TextDraw.new("Message: " + @message.join).draw(10, 180)

    left_chars, right_chars = @chooser.choices
    TextDraw.new("Left:").draw(10, 60)
    TextDraw.new(left_chars.to_s).draw(10, 40)
    TextDraw.new("Right:").draw(100, 60)
    TextDraw.new(right_chars.to_s).draw(100, 40)
  end

  def keyboard_down(key, special)
    exit if key == 27
  end

  def special_keyboard_down(key, special)
    case key
    when 100 then @chooser.choose(:left)  # Blink left
    when 102 then @chooser.choose(:right) # Blink right
    when 103 then pop                     # Blink both
    end
  end

  private

  def pop
    if @chooser.has_choices?
      @chooser.pop
    else
      @message.pop
    end
  end
end

EyeTest.new.show(1000, 1000)

font.rb

{
  'A' => [[ [0,0], [2,5], [4,0] ], [ [1,2], [3,2] ]],
  'B' => [[ [0,0], [0,5], [2,5], [3,4], [2,3], [3,2], [3,1], [2,0], [0,0] ], [ [0,3], [2,3] ]],
  'C' => [[ [4,1], [3,0], [1,0], [0,1], [0,4], [1,5], [3,5], [4,4] ]],
  'D' => [[ [0,0], [0,5], [2,5], [3,4], [3,1], [2,0], [0,0] ]],
  'E' => [[ [3,0], [0,0], [0,5], [3,5] ], [ [0,3], [2,3] ]],
  'F' => [[ [0,0], [0,5], [3,5] ], [ [0,3], [2,3] ]],
  'G' => [[ [2,2], [4,2], [4,1], [3,0], [1,0], [0,1], [0,4], [1,5], [3,5], [4,4] ]],
  'H' => [[ [0,0], [0,5] ], [ [3,0], [3,5] ], [ [0,3], [3,3] ]],
  'I' => [[ [1,0], [1,5] ], [ [0,0], [2,0] ], [ [0,5], [2,5] ]],
  'J' => [[ [0,1], [1,0], [2,0], [3,1], [3,5] ]],
  'K' => [[ [0,0], [0,5] ], [ [3,5], [0,3], [3,0] ]],
  'L' => [[ [0,5], [0,0], [3,0] ]],
  'M' => [[ [0,0], [0,5], [2,2], [4,5], [4,0] ]],
  'N' => [[ [0,0], [0,5], [3,0], [3,5] ]],
  'O' => [[ [0,1], [0,4], [1,5], [3,5], [4,4], [4,1], [3,0], [1,0], [0,1] ]],
  'P' => [[ [0,0], [0,5], [2,5], [3,4], [3,3], [2,2], [0,2] ]],
  'Q' => [[ [0,1], [0,4], [1,5], [3,5], [4,4], [4,1], [3,0], [1,0], [0,1] ], [ [2,2], [5,-1] ]],
  'R' => [[ [0,0], [0,5], [2,5], [3,4], [3,3], [2,2], [0,2] ], [ [2,2], [3,0] ]],
  'S' => [[ [0,1], [1,0], [2,0], [3,1], [3,2], [0,3], [0,4], [1,5], [2,5], [3,4] ]],
  'T' => [[ [0,5], [4,5] ], [ [2,0], [2,5] ]],
  'U' => [[ [0,5], [0,1], [1,0], [3,0], [4,1], [4,5] ]],
  'V' => [[ [0,5], [2,0], [4,5] ]],
  'W' => [[ [0,5], [1,0], [2,2], [3,0], [4,5] ]],
  'X' => [[ [0,0], [4,5] ], [ [0,5], [4,0] ]],
  'Y' => [[ [0,5], [2,3], [4,5] ], [ [2,3], [2,0] ]],
  'Z' => [[ [0,5], [4,5], [0,0], [4,0] ]],
  'a' => [[ [3,3], [3,0] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
  'b' => [[ [0,5], [0,0] ], [ [0,1], [1,0], [2,0], [3,1], [3,2], [2,3], [1,3], [0,2] ]],
  'c' => [[ [3,2], [2,3], [1,3], [0,2], [0,1], [1,0], [2,0], [3,1] ]],
  'd' => [[ [3,5], [3,0] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
  'e' => [[ [0,1], [3,2], [2,3], [1,3], [0,2], [0,1], [1,0], [2,0], [3,1] ]],
  'f' => [[ [1,0], [1,4], [2,5] ], [ [0,3], [2,3] ]],
  'g' => [[ [3,3], [3,-1], [2,-2], [1,-2], [0,-1] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
  'h' => [[ [0,5], [0,0] ], [ [0,3], [1,3], [2,2], [2,0] ]],
  'i' => [[ [0,0], [0,3] ], [ [0,5] ]],
  'j' => [[ [0,-1], [1,-2], [2,-1], [2,3] ], [ [2,5] ]],
  'k' => [[ [0,0], [0,5] ], [ [2,3], [0,2], [2,0] ]],
  'l' => [[ [0,0], [0,5] ]],
  'm' => [[ [0,0], [0,3], [1,3], [2,2], [2,3], [3,3], [4,2], [4,0] ], [ [2,2], [2,0] ]],
  'n' => [[ [0,0], [0,3], [1,3], [2,2], [2,0] ]],
  'o' => [[ [3,2], [2,3], [1,3], [0,2], [0,1], [1,0], [2,0], [3,1], [3,2] ]],
  'p' => [[ [0,-2], [0,3] ], [ [0,2], [1,3], [2,3], [3,2], [3,1], [2,0], [1,0], [0,1] ]],
  'q' => [[ [3,-2], [3,3] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
  'r' => [[ [0,0], [0,3] ], [ [0,2], [1,3], [2,2] ]],
  's' => [[ [0,1], [0,0], [2,0], [2,1], [0,2], [0,3], [2,3], [2,2] ]],
  't' => [[ [1,5], [1,1], [2,0] ], [ [0,3], [2,3] ]],
  'u' => [[ [0,3], [0,1], [1,0], [2,1] ], [ [2,3], [2,0] ]],
  'v' => [[ [0,3], [1,0], [2,3] ]],
  'w' => [[ [0,3], [1,0], [2,3], [3,0], [4,3] ]],
  'x' => [[ [0,3], [2,0] ], [ [0,0], [2,3] ]],
  'y' => [[ [0,3], [1,0] ], [ [2,3], [1,0], [0,-2] ]],
  'z' => [[ [0,3], [2,3], [0,0], [2,0] ]],
  '0' => [[ [0,1], [0,4], [1,5], [2,5], [3,4], [3,1], [2,0], [1,0], [0,1] ], [ [2,4], [1,1] ]],
  '1' => [[ [0,4], [1,5], [1,0] ], [ [0,0], [2,0] ]],
  '2' => [[ [0,4], [1,5], [2,5], [3,4], [0,0], [3,0] ]],
  '3' => [[ [0,4], [1,5], [2,5], [3,4], [2,3], [3,2], [3,1], [2,0], [1,0], [0,1] ]],
  '4' => [[ [0,5], [0,3], [3,3] ], [ [3,5], [3,0] ]],
  '5' => [[ [3,5], [0,5], [0,3], [2,3], [3,2], [3,1], [2,0], [1,0], [0,1] ]],
  '6' => [[ [2,5], [0,2], [0,1], [1,0], [2,0], [3,1], [3,2], [2,3], [1,3], [0,2] ]],
  '7' => [[ [0,5], [3,5], [1,0] ]],
  '8' => [[ [0,4], [1,5], [2,5], [3,4], [3,3], [0,2], [0,1], [1,0], [2,0], [3,1], [3,2], [0,3], [0,4] ]],
  '9' => [[ [1,0], [3,3], [3,4], [2,5], [1,5], [0,4], [0,3], [1,2], [2,2], [3,3] ]],
  ' ' => [],
  '.' => [[ [0,0] ]],
  ':' => [[ [0,1] ], [[0,3]] ],
  '?' => [[ [0,4], [1,5], [2,4], [2,3], [1,2] ], [ [1,0] ]]
}

text_draw.rb

class TextDraw
  CHARACTERS = eval(File.read("font.rb"))

  def initialize(string)
    @string = string
  end

  def draw(x, y)
    glPushMatrix
      glLoadIdentity
      glTranslate(x, y, 0)
      glColor(1.0, 1.0, 1.0)
      characters.each do |char|
        draw_character(char)
        glTranslate(character_width(char), 0, 0)
      end
    glPopMatrix
  end

  def width
    characters.inject(0) do |sum, c|
      sum + character_width(c)
    end
  end

  protected

  def characters
    @string.scan(/./)
  end

  def draw_character(char)
    polys = CHARACTERS[char] || CHARACTERS['?']
    polys.each do |poly|
      glBegin(poly.size == 1 ? GL_POINTS : GL_LINE_STRIP)
      poly.each do |x, y|
        glVertex(x, y)
      end
      glEnd
    end
  end

  def character_width(char)
    return 4 if char == " "
    polys = CHARACTERS[char] || CHARACTERS['?']
    xs = polys.map { |poly| poly.map { |x,y| x } }.flatten
    xs.max - xs.min + 1
  end
end