# File lib/as_physics.rb, line 6
    def initialize(w, h, density, offset)
      hw = w/2; hh = h/2
      verts = [
               vec2(-hw, -hh),
               vec2(-hw,  hh),
               vec2( hw,  hh),
               vec2( hw, -hh),
              ]
      
      mass = w*h*density
      moment = CP.moment_for_poly(mass, verts, offset)
      
      super(CP::Body.new(mass, moment), verts, offset)
    end