// switch to new proximity database -- just for demo purposes
void newPD (ProximityDatabase& pd)
{
// delete this boid's token in the old proximity database
delete proximityToken;
// allocate a token for this boid in the proximity database
proximityToken = pd.allocateToken (this);
}
void Boid::newPD( ProximityDatabase& pd ) {
delete proximityToken;
proximityToken = pd.allocateToken(this);
}