Shaft Shearing

shaft_shearing.rb

require "graphics"

class ShaftShearing < Graphics::Simulation
  # I should soooo make one called "fruit flies ponder a pond where the bg is
  # like [10, 21, 36], and there is a circle at the end of the bezier
  CLEAR_COLOR = [36, 30, 10]

  def initialize
    super 800, 450, 24
    @points = [[-1, -1], [-1, h], [w, h], [w, -1]]
    # @points = 100.times.map { |i| [
    #   w/2*Math.cos(2*Math::PI*i/30.0)+w/2,
    #   h/2*Math.sin(2*Math::PI*i/30.0)+h/2,
    # ] }
    color.default_proc = -> h, k { k }

    @drawers = []
    n        = 500

    n.times do |i|
      color   = [255, 255, 255]
      points  = @points.dup
      percent =
        Math.sin(Math.sin(Math.sin(Math.sin(Math.sin(
          Math.sin(Math::PI*(i/n.to_f%1)-Math::PI/2)
        )))))
        ./(
          Math.sin(Math.sin(Math.sin(Math.sin(Math.sin(
            1
          )))))
        ).+(1)./(2)
      @drawers[i] = []
      200.times do
        points << points.first
        crnt_points = points
        @drawers[i] << lambda { draw_lines_between crnt_points, color }
        points = percentages_between points, percent
      end
    end
  end

  def draw(ticks)
    clear
    @drawers[ticks % @drawers.length].each(&:call)
  end

  def dim((r, g, b), percent)
    end_r, end_g, end_b = CLEAR_COLOR
    [ r + (end_r-r)*percent,
      g + (end_g-g)*percent,
      b + (end_b-b)*percent,
    ]
  end

  def draw_lines_between(points, color)
    points.each_cons 2 do |(x1, y1), (x2, y2)|
      line x1, y1, x2, y2, color
    end
  end

  # feels like if I think about calculus for a little bit, I might be able to
  # come up with an equation for htis so that we don't have to repeatedly invoke it
  def percentages_between(points, percent)
    points.each_cons(2).map do |(x1, y1), (x2, y2)|
      [x1+(x2-x1)*percent, y1+(y2-y1)*percent]
    end
  end

  def rand_point
    return [rand(w), rand(h)]
    [rand(5*w)-2*w, rand(5*h)-2*h]
  end
end

ShaftShearing.new.run