INeighborQueryJobWrapper

Neighbor queries are implementations of INeighborQueryJobWrapper. Given two sets of entities, they find MaxNumNeighbors neighbors for each entity from the first set. Normally this is MaxNumNeighbors nearest entities restricted by field of view FOV, but generally other criteria of a neighborhood could be implemented. The resulting neighborhood is passed into neighbor behaviors.

Implementing a Neighbor Query

To implement your own neighbor query, create a class implementing the INeighborQueryJobWrapper interface. Mark it with [JobWrapper], this will make it show up in the editor. The schedule method is expected to schedule a job which finds neighbors and writes them to the neighbors array. See below for details about the format of neighbors, which the behaviors will expect. All the data necessary to find the neighbors is passed inside NeighborQueryParams.

MyNeighborQueryJobWrapper.cs

[JobWrapper]
public class MyNeighborQueryJobWrapper : INeighborQueryJobWrapper
{
    public JobHandle Schedule(
        SystemBase systemBase,
        in NeighborQueryParams neighborQueryParams,
        in NativeArray<NeighborMatch> neighbors,
        in JobHandle dependency)
    {
        var handle = new MyNeighborQueryJob(neighborQueryParams).Schedule(dependency);
        return handle;
    }
}

Neighbors Array Format

The neighbors array is passed in preallocated with MaxNumNeighbors elements for each entity. The expected format is that indexes i * MaxNumNeighbors to i * MaxNumNeighbors + MaxNumNeighbors - 1 contain neighbors for entity i from neighborQueryParams.BaseBehaviorParams. Each NeighborMatch element contains the index of neighbor j inside neighborQueryParams.OtherBehaviorParams. Elements in the array where OtherIndex is -1 signify none neighbor.

INeighborQueryJobWrapper.cs

public struct NeighborMatch
{
    public int OtherIndex; // index of the neighbor inside OtherBehaviorParams
    public float DistanceToOrigin; // distance between origins
    public float DistanceToSurface; // distance between origins minus the radii of the two entities
}