hasChangedMovement() {
        let b = this._bHasChangedMovement;
        this._bHasChangedMovement = false;
        return b;
    }
/**
     * returns true if the entity has changed its movement
     * i.e. its speed vector has changed, or its angle has changed
     */
returns true if the entity has changed its movement
i.e. its speed vector has changed, or its angle has changed
returns true if the entity has changed its movement i . e . its speed vector has changed or its angle has changed
hasChangedMovement() {
        let b = this._bHasChangedMovement;
        this._bHasChangedMovement = false;
        return b;
    }
hasChangedMovement ( ) { let b = this . _bHasChangedMovement ; this . _bHasChangedMovement = false ; return b ; }
returns true if the entity has changed its movement
 i.e.
returns true if the entity has changed its movement i . e .