virtual PhysicsObject * make_copy() const =0
dynamic copy.
Describes a particle that requires representation by a point (pixel, sparkle, billboard) ...
virtual void output(ostream &out) const
Write a string representation of this instance to <out>.
An individual, physically-modelable particle abstract base class.
virtual void write(ostream &out, int indent=0) const
Write a string representation of this instance to <out>.