Walkers

walkers1.rb

# video @ https://vimeo.com/217144282
require 'graphics'

class Walkers < Graphics::Simulation
  def initialize
    super 800, 600, 24
    color.default_proc = -> h, k { k }
    @walkers = 50.times.map do
      length = 15
      colour = [
        rand(200)+55,
        rand(200)+55,
        rand(200)+55,
      ]
      Walker.new rand(w), rand(h), rand(2*Math::PI), colour, length
    end
  end

  def update(n)
    @walkers.each &:update
  end

  def draw(n)
    clear
    @walkers.each { |w| w.draw self }
  end
end


class Walker
  attr_accessor :x, :y, :ø, :colour, :length, :segments

  def initialize(x, y, ø, colour, length)
    self.x        = x
    self.y        = y
    self.ø        = ø
    self.colour   = colour
    self.length   = length
    self.segments = [[x, y]]
  end

  TWO_PI = 2*Math::PI
  def update
    self.ø += rand(TWO_PI)
    self.ø %= TWO_PI
    self.x += 10 * Math.cos(ø)
    self.y += 10 * Math.sin(ø)
    segments.unshift [x, y]
    segments.pop if segments.length > length
  end

  def draw(canvas)
    segments.each_cons 2 do |(x1, y1), (x2, y2)|
      canvas.line x1, y1, x2, y2, colour
    end
  end
end

Walkers.new.run

walkers2.rb

require 'graphics'

class Walkers < Graphics::Simulation
  def initialize
    super 800, 600, 24
    color.default_proc = -> h, k { k }
    @walkers = 200.times.map do
      length = 15
      colour = [
        rand(255),
        rand(255),
        rand(255),
      ]
      Walker.new rand(w), rand(h), rand(2*Math::PI), colour, length
    end
  end

  def update(n)
    @walkers.each &:update
  end

  def draw(n)
    # clear
    @walkers.each { |w| w.draw self }
  end
end


class Walker
  attr_accessor :x, :y, :ø, :colour, :length, :segments

  def initialize(x, y, ø, colour, length)
    self.x        = x
    self.y        = y
    self.ø        = ø
    self.colour   = colour
    self.length   = length
    self.segments = [[x, y]]
  end

  TWO_PI = 2*Math::PI
  def update
    self.ø += rand(TWO_PI)
    self.ø %= TWO_PI
    self.x += 10 * Math.cos(ø)
    self.y += 10 * Math.sin(ø)
    segments.unshift [x, y]
    segments.pop if segments.length > length
  end

  def draw(canvas)
    segments.each_cons 2 do |(x1, y1), (x2, y2)|
      canvas.line x1, y1, x2, y2, colour
      canvas.line x1+1, y1, x2+1, y2, colour
      canvas.line x1, y1+1, x2, y2+1, colour
    end
  end
end

Walkers.new.run

walkers3.rb

require 'graphics'

class Walkers < Graphics::Simulation
  def initialize
    super 1000, 600, 24
    color.default_proc = -> h, k { k }
    @walkers = 30.times.map do
      length = 15
      colour = [
        rand(200)+55,
        rand(200)+55,
        rand(200)+55,
      ]
      Walker.new 30, rand(w), rand(h), rand(2*Math::PI), colour, length, w, h
    end
  end

  def update(n)
    @walkers.each &:update
  end

  def draw(n)
    clear
    @walkers.each { |w| w.draw self }
  end
end


class Walker
  attr_accessor :x, :y, :ø, :colour, :length, :segments, :stride, :xmax, :ymax

  def initialize(stride, x, y, ø, colour, length, xmax, ymax)
    self.x        = x
    self.y        = y
    self.stride   = stride
    self.ø        = ø
    self.colour   = colour
    self.length   = length
    self.xmax     = xmax
    self.ymax     = ymax
    self.segments = [[x, y]]
  end

  TWO_PI = 2*Math::PI
  def update
    self.ø += rand(TWO_PI)
    self.ø %= TWO_PI
    self.x += stride * Math.cos(ø)
    self.y += stride * Math.sin(ø)
    segments.unshift [x, y]

    if x < 0
      self.x *= -1
    elsif xmax < x
      self.x -= 2*(x-xmax)
    end

    if y < 0
      self.y *= -1
    elsif ymax < y
      self.y -= 2*(y-ymax)
    end

    segments.pop if segments.length > length+2
  end

  def draw(canvas)
    percent = rand
    points = segments
    points = percentages_between points, percent
    points = percentages_between points, percent
    points = percentages_between points, percent
    points = percentages_between points, percent
    draw_lines_between canvas, points, colour, rand(3), rand(3)
  end

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

  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
end

Walkers.new.run