int PointSet::AddPointReuse ()
{
	xref ndx;	
	if ( NumPoints() < mBuf[0].max-1 )
		AddElem ( 0, ndx );
	else
		RandomElem ( 0, ndx );
	return ndx;
}
int FluidSystem::AddPointReuse ()
{
	xref ndx;	
	Fluid* f;
	if ( NumPoints() <= mBuf[0].max-2 )
		f = (Fluid*) AddElem ( 0, ndx );
	else
		f = (Fluid*) RandomElem ( 0, ndx );

	f->sph_force.Set(0,0,0);
	f->vel.Set(0,0,0);
	f->vel_eval.Set(0,0,0);
	f->next = 0x0;
	f->pressure = 0;
	f->density = 0;
	return ndx;
}