fix mouse joint example

Author: monkstone

external_library/gem/pbox2d/mouse_joint/boundary.rb

@@ -36,7 +36,7 @@ def display
     stroke(127)
     fill(127)
     stroke_weight(1)
-    rect_mode(Java::ProcessingCore::CENTER)
+    rect_mode(Java::ProcessingCore::PConstants::CENTER)
     a = b.get_angle
     push_matrix
     translate(x, y)

external_library/gem/pbox2d/mouse_joint/box.rb

@@ -1,7 +1,7 @@
 # The Nature of Code
 # Daniel Shiffman
 # http://natureofcode.com
-
+require 'forwardable'
 # A rectangular box
 class Box
   extend Forwardable
@@ -34,7 +34,7 @@ def display
     pos = box2d.body_coord(body)
     # Get its angle of rotation
     a = body.getAngle
-    rect_mode(Java::ProcessingCore::CENTER)
+    rect_mode(Java::ProcessingCore::PConstants::CENTER)
     push_matrix
     translate(pos.x, pos.y)
     rotate(a)

external_library/gem/pbox2d/mouse_joint/mouse_joint.rb

@@ -9,13 +9,15 @@
 require_relative 'boundary'
 require_relative 'spring'
 require_relative 'dummy_spring'
-require 'forwardable'
 
 # A reference to our box2d world
 attr_reader :box2d, :boundaries, :box, :spring
+def settings
+  size(640, 360)
+end
 
 def setup
-  size(640, 360)
+  sketch_title('Mouse Joint')
   # Initialize box2d physics and create the world
   @box2d = Box2D.new self
   box2d.create_world