first crack

Author: monkstone

docs/_config.yml

@@ -1,28 +1,11 @@
-# Welcome to Jekyll!
-#
-# This config file is meant for settings that affect your whole blog, values
-# which you are expected to set up once and rarely edit after that. If you find
-# yourself editing this file very often, consider using Jekyll's data files
-# feature for the data you need to update frequently.
-#
-# For technical reasons, this file is *NOT* reloaded automatically when you use
-# 'bundle exec jekyll serve'. If you change this file, please restart the server process.
-
-# Site settings
-# These are used to personalize your new site. If you look in the HTML files,
-# you will see them accessed via {{ site.title }}, {{ site.email }}, and so on.
-# You can create any custom variable you would like, and they will be accessible
-# in the templates via {{ site.myvariable }}.
-title: Your awesome title
-email: [email protected]
+title: Vecmath gem for Visor etc.
+email: [email protected]
 description: >- # this means to ignore newlines until "baseurl:"
-  Write an awesome description for your new site here. You can edit this
-  line in _config.yml. It will appear in your document head meta (for
-  Google search results) and in your feed.xml site description.
+  Her we describe how to use some cool JRubyArt features in Visor
 baseurl: "" # the subpath of your site, e.g. /blog
 url: "" # the base hostname & protocol for your site, e.g. http://example.com
-twitter_username: jekyllrb
-github_username:  jekyll
+twitter_username: monkstoneT
+github_username:  monkstone
 
 # Build settings
 markdown: kramdown

docs/_posts/2019-03-01-welcome-to-jekyll.markdown

@@ -0,0 +1,97 @@
+---
+layout: post
+title:  "Welcome to Vecmath Gem for Visor"
+date:   2019-03-01 10:58:08 +0000
+categories: vecmath update
+---
+```ruby
+# ===== Default : Default
+GEM_HOME = '/home/tux/.gem/ruby/2.6.0'
+require 'vecmath'
+require 'forwardable'
+
+# Here we use the JRubyArt Vec2D class, and AppRender class (for vec.to_vertex)
+# Further we use the power of ruby (metaprogramming) to make Branch enumerable
+# and use Forwardable to define which enumerable methods we want to use.
+visor_class :Branch do
+  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 / 3
+  attr_reader :position, :dir, :path, :children, :xbound, :speed, :ybound, :app
+
+  def initialize(pos, dir, speed)
+    @renderer ||= AppRender.new(graphics)
+    @position = pos
+    @dir = dir
+    @speed = speed
+    @path = []
+    @children = []
+    @xbound = Boundary.new(0, width)
+    @ybound = Boundary.new(0, height)
+    path << pos
+  end
+
+  def run
+    grow
+    display
+  end
+
+  private
+
+  # NB: use of both rotate! (changes original) rotate (returns a copy) of Vec2D
+  def grow
+    check_bounds(position + (dir * speed)) if path.length < MAX_LEN
+    @position += (dir * speed)
+    dir.rotate!(rand(-0.5..0.5) * THETA)
+    path << position
+    if (length < MAX_GEN) && (rand < BRANCH_CHANCE)
+      branch_dir = dir.rotate(rand(-0.5..0.5) * BRANCH_THETA)
+      self << Branch.new(position.copy, branch_dir, speed * 0.99)
+    end
+    each(&:grow)
+  end
+
+  def display
+    begin_shape
+    stroke(255)
+    no_fill
+    path.each { |vec| vec.to_vertex(@renderer) }
+    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
+  end
+end
+
+# we are looking for excluded values
+Boundary = Struct.new(:lower, :upper) do
+  def exclude?(val)
+    !(lower...upper).cover? val
+  end
+end
+
+@root = Branch.new(
+    Vec2D.new(0, height / 2),
+    Vec2D.new(1, 0),
+    10.0
+)
+
+def draw
+  background(0)
+  root.run
+end
+
+```