Sketch featuring Vec2D to_curve_vertex (JRubyArt)

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# Soft Body by Ira Greenberg
# Softbody dynamic simulation using curve_vertex
# and curve_tightness (and new Vec2D to_curve_vertex)
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require 'jruby_art'

# SoftBody class wrapped JRubyArt sketch features Vec2D :to_curve_vertex
class SoftBody < Processing::App
  attr_reader :accel, :center, :frequency, :radius, :rot_angle
  attr_reader :organic_constant, :nodes, :renderer, :angle, :node_start
  SPRINGING = 0.0009
  DAMPING = 0.98
  NODES = 5

  def setup
    size 640, 360
    @renderer = AppRender.new(self)
    init_node
    no_stroke
    frame_rate 30
  end

  def init_node
    @accel = Vec2D.new
    @center = Vec2D.new(width / 2, height / 2)
    @radius = 45
    @organic_constant = 1
    @rot_angle = -90
    @nodes = (0...NODES).map { Vec2D.new }
    @frequency = (0...NODES).map { rand(5..12) }
    @angle = Array.new(NODES, 0)
  end

  def draw
    fill(0, 100)
    rect(0, 0, width, height)
    update
    draw_shape
    move_shape
  end

  def draw_shape
    curve_tightness(organic_constant)
    fill 255
    begin_shape
    nodes.each { |vec| vec.to_curve_vertex(renderer) }
    nodes.take(NODES - 1).each { |vec| vec.to_curve_vertex(renderer) }
    end_shape(Java::ProcessingCore::PConstants::CLOSE)
  end

  def update
    delta = Vec2D.new(mouse_x - center.x, mouse_y - center.y)
    delta *= SPRINGING
    @accel += delta
    @center += accel
    @accel *= DAMPING
    @organic_constant = 1 - (((accel.x).abs + (accel.y).abs) * 0.1)
    @node_start = create_start
  end

  def create_start
    (0...NODES).map do |n|
      Vec2D.new(
        center.x + DegLut.cos(n * (360 / NODES)) * radius,
        center.y + DegLut.sin(n * (360 / NODES)) * radius
        )
    end
  end

  def move_shape
    (0...NODES).each do |i|
      nodes[i] = Vec2D.new(
      node_start[i].x + DegLut.sin(angle[i]) * (accel.x * 2),
      node_start[i].y + DegLut.sin(angle[i]) * (accel.y * 2)
      )
      angle[i] = frequency[i] + angle[i]
    end
  end
end

SoftBody.new(title: 'Soft Body')