arc tesselation example

Author: monkstone

demo/arc_tesselation.rb

@@ -0,0 +1,88 @@
+#!/usr/bin/env jruby
+require 'picrate'
+
+# After an openprocessing sketch by Manoylov AC
+# https://www.openprocessing.org/user/23616/
+# press mouse to generate new pattern
+# use `c` key to toggle colored / greyscale
+# use 's' to save
+
+class ArcTesselation < Processing::App
+  attr_reader :cols, :coloured
+
+  PALETTE = %w[#152A3B #158ca7 #F5C03E #D63826 #0F4155 #7ec873 #4B3331].freeze
+
+  def settings
+    size(600, 600)
+  end
+
+  def setup
+    background 0
+    sketch_title 'Arc Tesselation'
+    # create a java primitive array of signed int
+    @cols = web_to_color_array(PALETTE)
+    stroke_weight 1.5
+    stroke_cap SQUARE
+    stroke(0, 200)
+    @coloured = true
+  end
+
+  def draw
+    arc_pattern
+  end
+
+  def sep_index(idx, length)
+    (idx - (length - 1) * 0.5).abs.floor
+  end
+
+  def sep_color(idx, number)
+    cols[sep_index(idx - 1, number + 1)]
+  end
+
+  def arc_pattern
+    circ_number = rand(4..10)
+    block_size = rand(30..70)
+    back_color = coloured ? cols.last : 255
+    fill(back_color)
+    rect(0, 0, width, height)
+    half_block = block_size / 2
+    two_block = 2 * block_size
+    grid(width + two_block, height + two_block, block_size, block_size) do |x, y|
+      push_matrix
+      translate x, y
+      rotate HALF_PI * rand(0..4)
+      circ_number.downto(0) do |i|
+        diam = two_block * i / (circ_number + 1)
+        ccolor = i < 2 || !coloured ? back_color : sep_color(i, circ_number)
+        fill ccolor
+        arc(-half_block, -half_block, diam, diam, 0, HALF_PI)
+        arc(half_block, half_block, diam, diam, PI, PI + HALF_PI)
+      end
+      pop_matrix
+    end
+    no_loop
+  end
+
+  def mouse_pressed
+    @cols = shuffle_array(cols) if coloured
+    loop
+  end
+
+  def key_typed
+    case key
+    when 'c', 'C'
+      @coloured = !coloured
+    when 's', 'S'
+      save(data_path('arc_pattern.png'))
+    end
+  end
+
+  # do a ruby shuffle! on a primitive java array
+  def shuffle_array(arr)
+    cols = arr.to_a
+    cols.shuffle!
+    cols.to_java(Java::int)
+  end
+end
+
+ArcTesselation.new

demo/chladni.rb

@@ -23,7 +23,7 @@ class Chladni < Processing::App
   attr_reader :m, :n, :epsilon, :recompute
 
   def settings
-    size(500, 500)
+    size(500, 500, P2D)
   end
 
   def setup