mycelium box

Author: monkstone

contributed/library/branch3D/branch3D.rb

@@ -0,0 +1,79 @@
+require 'forwardable'
+require_relative './rotator'
+
+class Branch
+  include Enumerable
+  extend Forwardable
+  def_delegators(:@children, :<<, :each, :length)
+  # variance angle for growth direction per time step
+  THETA = Math::PI / 6
+  # max segments per branch
+  MAX_LEN = 100
+  # max recursion limit
+  MAX_GEN = 3
+  # branch chance per time step
+  BRANCH_CHANCE = 0.05
+  # branch angle variance
+  BRANCH_THETA = Math::PI / 4
+  attr_reader :position, :dir, :path, :children, :xbound, :speed, :ybound, :app, :zbound
+
+  def initialize(app, pos, dir, speed)
+    @app = app
+    @position = pos
+    @dir = dir
+    @speed = speed
+    @path = []
+    @children = []
+    @xbound = Boundary.new(-600, 600)
+    @ybound = Boundary.new(-150, 150)
+    @zbound = Boundary.new(-150, 150)
+    path << pos
+  end
+
+  def run
+    grow
+    display
+  end
+
+  private
+
+  def grow
+    check_bounds(position + (dir * speed))
+    @position += (dir * speed)
+    Rotate.rotate_x!(dir, rand(-0.5..0.5) * THETA)
+    Rotate.rotate_y!(dir, rand(-0.5..0.5) * THETA)
+    Rotate.rotate_z!(dir, rand(-0.5..0.5) * THETA)
+    path << position
+    if (length < MAX_GEN) && (rand < BRANCH_CHANCE)
+      branch_dir = dir.copy
+      Rotate.rotate_x!(branch_dir, rand(-0.5..0.5) * BRANCH_THETA)
+      Rotate.rotate_y!(branch_dir, rand(-0.5..0.5) * BRANCH_THETA)
+      Rotate.rotate_z!(branch_dir, rand(-0.5..0.5) * BRANCH_THETA)
+      self << Branch.new(app, position.copy, branch_dir, speed * 0.99)
+    end
+    each(&:grow)
+  end
+
+  def display
+    app.begin_shape
+    app.stroke 255
+    app.stroke_weight 0.5
+    app.no_fill
+    path.each { |vec| vec.to_vertex(app.renderer) }
+    app.end_shape
+    each(&:display)
+  end
+
+  def check_bounds(pos)
+    dir.x *= -1 if xbound.exclude? pos.x
+    dir.y *= -1 if ybound.exclude? pos.y
+    dir.z *= -1 if zbound.exclude? pos.z
+  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

contributed/library/branch3D/rotator.rb

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+# Rotator module is required because rotate is not implemented for PiCrate Vec3D
+# NB: we use quaternions in ArcBall (avoiding possible gimbal lock)
+module Rotate
+  def self.rotate_x!(vec, theta)
+    co = Math.cos(theta)
+    si = Math.sin(theta)
+    zz = co * vec.z - si * vec.y
+    vec.y = si * vec.z + co * vec.y
+    vec.z = zz
+    vec
+  end
+
+  def self.rotate_y!(vec, theta)
+    co = Math.cos(theta)
+    si = Math.sin(theta)
+    xx = co * vec.x - si * vec.z
+    vec.z = si * vec.x + co * vec.z
+    vec.x = xx
+    vec
+  end
+
+  def self.rotate_z!(vec, theta)
+    co = Math.cos(theta)
+    si = Math.sin(theta)
+    xx = co * vec.x - si * vec.y
+    vec.y = si * vec.x + co * vec.y
+    vec.x = xx
+    vec
+  end
+end

contributed/mycelium_box.rb

@@ -0,0 +1,33 @@
+# Simple recursive branching system inspired by mycelium growth
+# After an original sketch by Karsten Schmidt
+# https://github.com/learn-postspectacular/sac-workshop-2013/blob/master/MyceliumBox/MyceliumBox.pde
+# translated to JRubyArt by Martin Prout 2018
+
+load_library :branch3D
+
+attr_reader :renderer, :root
+
+def setup
+  sketch_title 'Mycelium Box'
+  ArcBall.init self
+  @renderer = AppRender.new(self)
+  @root = Branch.new(
+    self,
+    Vec3D.new(0, 10, 10),
+    Vec3D.new(1, 0, 0),
+    6.0
+  )
+end
+
+def draw
+  background(0)
+  no_fill
+  stroke_weight 2
+  stroke(200, 0, 0, 100)
+  box(1200, 300, 300)
+  root.run
+end
+
+def settings
+  size(1280, 600, P3D)
+end