NavMesh

Let’s set up the navigation mesh.

• Select object “Playfield/Plane”
• Add a NavMeshSurface component
• Hit “Bake”

NavMeshObstacle

Our NPCs need to navigate around the buildings.

• Add a NavMeshObstacle component to each of the buildings and the trees
  • Mark the “Carve” checkbox
  • Un-mark the “Carve Only Stationary” box
  • Don’t do the roads. We don’t want NPCs to avoid roads
• You may need to re-bake the NavMesh on “Playfield/Plane”

It should look like this now:

NavMeshAgent and AIPilot

• Add a NavMeshAgent component to the “Character.prefab”
  • Set the Stopping Distance to 2
• Create a new class called AIPilot
• Inherit from Pilot
• Override the Start() function
  • Get the NavMeshAgent and store that in a member variable
  • Set NavMeshAgent.updatePosition to false
  • Set NavMeshAgent.updateRotation to false
    • Our Character class will be doing the movement
  • Copy Character.m_walkSpeed into NavMeshAgent.speed
  • Call base.Start()
• Override the GetInput() function
  • Use NavMeshAgent.desiredVelocity to set up the movement vector in your CharInput
    • Remember that desiredVelocity has a scale of 0 to speed. You’ll need to re-scale this into the 0 to 1 range
  • Make the facing angle of CharInput match the direction of movement
  • Return your CharInput
  • Do not call base.GetInput(). We do not want the keyboard controls.
• Override the Reset() function
  • Copy transform.position into NavMeshAgent.nextPosition
    • The character was moved by Character.Update(), and the agent needs to be updated manually
  • Call base.Reset()
• Remove the Pilot from “Character.prefab” and replace it with an AIPilot

The Character class should have no references to NavMeshAgent or AIPilot.
The AIPilot class interacts with the NavMeshAgent and updates the CharInput.

To test it out, add a temporary line to AIPilot.Start().
For testing, call NavMeshAgent.SetDestination(new Vector3(38.0f, 0.0f, 38.0f)).

Remove your test code (the SetDestination()), commit, and push.
Let’s get on to some AI.