Check whether a navmesh agent’s path is pending

Reminder to self. Here’s some code from state-based navigation logic. It’s in Update(), using a case statement on the state variable. Basically. we’ve got a destination, so set it, and go to the next state.

	// Set up navmesh.
	_navMeshAgent.speed = speed;
	// Set up the animator.
	_animator.SetFloat(animationParameter, _navMeshAgent.speed);
	// Start the navmesh.
	_navMeshAgent.destination = _collectibleBeingFetched.transform.position;
	_navMeshAgent.isStopped = false;
	state = CollectibleCarrierState.MovingToCollectible;
	break;
case CollectibleCarrierState.MovingToCollectible:
	// Are we there yet?
	if (_navMeshAgent.remainingDistance <= collectionPointStoppingDistance)
	{

Because of the break after setting the new state, the MovingToCollectible code doesn’t run until the next frame.

It worked most of the time, but sometimes, _navMeshAgent.remainingDistance would be zero. Ack!

The problem was the agent can take more than one frame to work out a path. Makes sense. For a long path calculation, you don’t want to block the main thread. Break the path computation up over a few frames.

My logic didn’t allow for that. To fix, check hasPath before seeing if we’re there yet:

	_navMeshAgent.destination = _collectibleBeingFetched.transform.position;
	_navMeshAgent.isStopped = false;
	state = CollectibleCarrierState.MovingToCollectible;
	break;
case CollectibleCarrierState.MovingToCollectible:
	// Have a path yet? It can take more than one frame.
	if (!_navMeshAgent.hasPath)
	{
		break;
	}
	// Are we there yet?
	if (_navMeshAgent.remainingDistance <= collectionPointStoppingDistance)
	{