this.phys = physics.kinematic;
this.dir_view2world = function(dir) { return dir.scale(this.zoom); };
this.view2world = function(pos) {
  var useren = window.rendersize.scale(this.zoom);
  if (window.mode === window.modetypes.stretch) {
    pos = pos.scale([window.rendersize.x/window.size.x, window.rendersize.y/window.size.y]);
    pos = pos.sub(window.rendersize.scale(0.5));
    pos = pos.scale(this.zoom);
    pos = pos.add(this.pos);
  }
  if (window.mode === window.modetypes.full) {
    pos = pos.sub(window.size.scale(0.5));
    pos = pos.scale(this.zoom);    
    pos = pos.add(this.pos);
  }
  return pos;
};
this.world2view = function(pos) {
  if (window.mode === window.modetypes.stretch) {
    pos = pos.sub(this.pos);
    pos = pos.scale(1.0/this.zoom);
    pos = pos.add(window.rendersize.scale(0.5));
  }
  if (window.mode === window.modetypes.full) {
    pos = pos.sub(this.pos);
    pos = pos.scale(1/this.zoom);
    pos = pos.add(window.size.scale(0.5));
  }
  return pos;
};

this.screenright = function() { return this.view2world(window.size).x; }
this.screenleft = function() { return this.view2world([0,0]).x; }

this.zoom = 1;