Using Navmesh Off Mesh Links

Unity Nav Mesh Links scripts are baked into the Quantum navmesh (Quantum.NavMesh.Links).

The following fields are used during baking:

• Bidirectional - creates two links in each direction
• CostModifier - used as input for Quantum.NavMeshLink.CostOverride
• Area Type - set the region of the link (see Toggling a Navmesh Link at Run-Time section)
• Activated - if not activated the link will be skipped during baking
• GameObject.name - used as input for Quantum Quantum.NavMeshLink.Name

Creating a Navmesh Link

• Create and configure a Unity NavMesh Link

  

• Bake the Quantum navmesh and verify the link by checking the gizmos for blue arrows (Quantum gizmo overlay menu, enable NavMeshLinks and select the QuantumMapData GameObject)

  

• Agents now considers the link for path-finding.

  

Toggling a Navmesh Link at Run-Time

Links can be toggled on and off during runtime using Quantum navmesh regions. They can be baked with a region id and toggled globally or per agent. Read the Regions Manual for more information.

Simple Region Mode

Choose the Area Type of the Unity NavMesh Link to set the region.

Advanced Region Mode

• Set the Area Type of the Unity NavMesh Link to a region detection area.
• Attach a MapNavMeshRegion script to the Unity NavMesh Link, set a region Id and set Cast Region to No Region.

Customization and Signals

The link data structure can be queried from the navmesh asset using NavMesh.Links. If a mapping from link index to name or vice-versa is required, a dictionary can be constructed.

The NavMeshPathfinder component has the following Link API:

• bool IsOnLink(FrameBase) - returns true when the agent is currently on a link
• int CurrentLink(FrameBase) - returns the current link index that points into NavMesh.Links or -1 when currently not on a link

Waypoint have link related WaypointFlags:

• LinkStart - this waypoint is the start of a link
• LinkStop - this waypoint is the end of a link
• RepathWhenReached - after reaching this waypoint the agent re-runs path finding

When setting a new target while the agent is on a link the agent will finish the current link before executing the path-finding (see WaypointFlag.RepathWhenReached).

No automatic re-pathing (for example for NavMeshAgentConfig.MaxRepathTimeout) will be executed as long as the agent is traversing a link.

By default the agent will traverse the link with its normal speed.

To take control of the agent movement when the link has been reached, the ISignalOnNavMeshWaypointReached signal can be used. Afterwards the agent can be disabled until an animation is complete or the movement can be overwritten in following ISignalOnNavMeshMoveAgent callbacks.

• Receiving any navigation callbacks requires enabled SimulationConfig.Navigation.EnabledNavigationCallbacks
• Receiving an ISignalOnNavMeshMoveAgent callback requires the NavMeshAgentConfig.MovementType to be set to Callback, it is possible to change the config of an agent at run-time.

The sample code performs a teleport when an agent steps on the link start waypoint.

C#

namespace Quantum
{
  using Photon.Deterministic;
  using UnityEngine.Scripting;

  [Preserve]
  public unsafe class NewQuantumSystem : SystemMainThread, ISignalOnNavMeshWaypointReached
  {
    public override void Update(Frame frame)
    {
    }

    public void OnNavMeshWaypointReached(Frame frame, EntityRef entity, FPVector3 waypoint, Navigation.WaypointFlag waypointFlags, ref bool resetAgent)
    {
      var agent = frame.Get<NavMeshPathfinder>(entity);
      var waypointIndex = agent.WaypointIndex;
      if ((waypointFlags & Navigation.WaypointFlag.LinkStart) == Navigation.WaypointFlag.LinkStart)
      {
        // There always is another waypoint after the LinkStart
        var linkDestination = agent.GetWaypoint(frame, waypointIndex + 1);
        f.Unsafe.GetPointer<Transform2D>(entity)->Position = linkDestination.XZ;
      }
    }
  }
}