working app just needs hooking up

Author: monkstone

lib/math_demo/circles.rb

@@ -0,0 +1,55 @@
+#!/usr/bin/env jruby
+require 'propane'
+require_relative 'circumcircle'
+require_relative 't_points'
+require_relative 'triangle_point'
+
+class Circles < Propane::App
+
+  def settings
+    size(800, 600, P2D)
+  end
+
+  def setup
+    sketch_title 'Circles'
+    color_mode(HSB, 360, 100, 100, 100)
+    reset
+    ellipse_mode(RADIUS)
+  end
+
+  def draw
+    fill(0, 0, 0)
+    no_stroke
+    reset if (frame_count % 8_000).zero?
+    @points.each do |point|
+      # change direction sometimes
+      point.direction Vec2D.random if rand > 0.96
+      point.update
+    end
+
+    # set the style of the circle
+    @dc = map1d(millis, 0..150_000, 0..360) # slowly changes hue
+    stroke((@c + @dc) % 360, 50, 100, 5)
+    no_fill
+
+    ## verifies if there is a circle and draw it
+    draw_circle @points unless @points.collinear?
+  end
+
+  def draw_circle(pts)
+    circumcircle = Circumcircle.new(@points.positions)
+    circumcircle.calculate
+    center_point = circumcircle.center
+    radius = circumcircle.radius
+    ellipse(center_point.x, center_point.y, radius, radius)
+  end
+
+  def reset
+    @c = rand(360)
+    @points = TrianglePoints.new
+    3.times { @points << TPoint.new(Vec2D.new(rand(5..width - 5), rand(5..height - 5))) }
+    background 0
+  end
+end
+
+Circles.new

lib/math_demo/triangle_points.rb lib/math_demo/t_points.rb

@@ -20,7 +20,12 @@ def <<(pt)
   end
 
   def collinear?
-    full? ? (points[0] - points[1]).cross(points[1] - points[2]).zero? : false
+    full? ? (positions[0] - positions[1]).cross(positions[1] - positions[2]).zero? : false
+  end
+
+  # returns positions as an array of Vec2D
+  def positions
+    points.map(&:pos)
   end
 
   def full?

lib/math_demo/triangle_point.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+# particle and triangle point
+class TPoint
+  include Propane::Proxy
+  attr_reader :pos, :vel, :accel, :xbound, :ybound
+  # attr_reader :width, :height # uncomment for testing
+
+  def initialize(position)
+    @pos = position
+    @vel = Vec2D.new
+    @accel = Vec2D.random
+    @xbound = Boundary.new(0, width)
+    @ybound = Boundary.new(0, height)
+  end
+
+  def direction(acc)
+    # direction of the acceleration is defined by the new angle
+    @accel = acc
+    # magnitude of the acceleration is proportional to the angle between
+    # acceleration and velocity
+    dif = acc.angle_between(vel)
+    dif = map1d(dif, 0..PI, 0.1..0.001)
+    @accel = acc * dif
+  end
+
+  def update
+    @vel += accel
+    @vel.set_mag(1.5) { vel.mag > 1.5 }
+    @pos += vel
+    check_bounds
+  end
+
+  private
+
+  def check_bounds
+    @vel.x *= -1 if xbound.exclude? pos.x
+    @vel.y *= -1 if ybound.exclude? pos.y
+  end
+end
+
+# we are looking for excluded values
+Boundary = Struct.new(:lower, :upper) do
+  def exclude?(val)
+    true unless (lower...upper).cover? val
+  end
+end

test/triangle_points_test.rb

@@ -1,14 +1,15 @@
 require_relative './test_helper'
-require_relative '../lib/math_demo/triangle_points'
+require_relative '../lib/math_demo/t_points'
+require_relative '../lib/math_demo/triangle_point'
 
 METHODS = %i(each map size shift clear [] collinear? full?).freeze
 
 class TrianglePointsTest < Minitest::Test
   def setup
     @tpoints = TrianglePoints.new
-    @tpoints << Vec2D.new(0, 0)
-    @tpoints << Vec2D.new(100, 100)
-    @tpoints << Vec2D.new(300, 300)
+    @tpoints << TPoint.new(Vec2D.new(0, 0))
+    @tpoints << TPoint.new(Vec2D.new(100, 100))
+    @tpoints << TPoint.new(Vec2D.new(300, 300))
   end
 
   def test_respond