Experiments with ruby-processing (processing-2.2.1) and JRubyArt for processing-3.0

Wednesday, 17 September 2014

Using the Range class in ruby processing

Since ruby-processing-2.6.3 the processing constrain function is actually implemented using the clip function of Range (this method has been added to Range in ruby-processing). However in ruby processing we should probably prefer to use the clip method directly, as I have here in my World class:-
# Class provides an OO way constraining a Mover in a 2D space
# use
# world = World.new((0..width), (0..height))
# world.constrain_mover(mover)
class World
  attr_reader :xrange, :yrange
  def initialize(xrange, yrange)
    @xrange, @yrange = xrange, yrange

  # @param mover is expected respond to loc, vel
  # that in turn respond to x and y getter/setters (Vec2D does this)

  def constrain_mover(mover)
    # Note clip functionality, extends Range in ruby-processing
    unless xrange.cover? mover.loc.x
      mover.vel.x *= -1
      mover.loc.x = xrange.clip mover.loc.x
    return if yrange.cover? mover.loc.y
    mover.vel.y *= -1
    mover.loc.y = yrange.clip mover.loc.y

For the sketch using this code see my fork Dan Shiffmans The Nature of Code Examples.

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I have developed JRubyArt and propane new versions of ruby-processing for JRuby- and processing-3.2.2