Visual debugging a Field of view angle

Questions & Answers
1

I’ve been trying for the past few days trying to figure out a way to visual debug a field of view angle.
I’ve tried it multiple ways with a custom editor and a mesh but its too confusing for me. Is there a simpler way to do this?
I have this field of view script for enemies to see the player. Everything works fine, but I could really use the debug to figure out view ranges.

I’ll post the code below:

void Update () {
 
        inCell = player.GetComponent<PlayerMovement> ().playerInCell;
 
        if(inCell == true)
        {
            Patrol ();
        }
        else
        {
            CheckForLights ();
            FieldOfView ();
            //Debug.Log ("A luz da cena está: " + sceneLightStatus + " e o player tem a luz: " + playerLightStatus);
 
            if(playerInSight == true && playerInRange == true)
            {
                inPursuit = true;
                agent.SetDestination (target.transform.position);
            }
            else
            {
                Patrol ();
            }
        }
    }
 
    void FixedUpdate()
    {
        Vector3 raycastDirection = target.transform.position - transform.position;
 
        RaycastHit hit;
 
        if(Physics.Raycast (transform.position, raycastDirection, out hit, viewDistance) && hit.transform.tag == "Player")
        {
            playerInRange = true;
        }
        else{
            Invoke ("ChangePlayerInRange", exitTime);
        }
    }
 
    void FieldOfView()
    {
        Vector3 targetDir = target.position - transform.position;
        float angle = Vector3.Angle (targetDir, transform.forward);
 
        minimumDistance = Vector3.Distance (target.transform.position, transform.position);
 
        if(angle < FOV * 0.5f && minimumDistance > 2f)
        {
            playerInSight = true;
        }
        else if(minimumDistance < 2f){
            playerBusted = true;
            playerInSight = true;
        }
        else{
            Invoke ("ChangePlayerInSight", exitTime);
            //playerInSight = false;
        }
    }
2

Well the field of view of your enemy is actually a cone. So if you want to create a mesh that visually shows that cone you just need something like this:

public Mesh CreateViewCone(float aAngle, float aDistance, int aConeResolution = 30)
{
    Vector3[] verts = new Vector3[aConeResolution +1];
    Vector3[] normals = new Vector3[verts.Length];
    int[] tris = new int[aConeResolution * 3];
    Vector3 a = Quaternion.Euler(-aAngle, 0, 0) * Vector3.forward * aDistance;
    Vector3 n = Quaternion.Euler(-aAngle, 0, 0) * Vector3.up;
    Quaternion step = Quaternion.Euler(0, 0, 360f / aConeResolution);
    verts[0] = Vector3.zero;
    normals[0] = Vector3.back;
    for (int i = 0; i < aConeResolution; i++)
    {
        normals[i+1] = n;
        verts[i+1] = a;
        a = step * a;
        n = step * n;
        tris[i * 3] = 0;
        tris[i * 3 + 1] = (i + 1) % aConeResolution + 1;
        tris[i * 3 + 2] = i+1;
    }
    Mesh m = new Mesh();
    m.vertices = verts;
    m.normals = normals;
    m.triangles = tris;
    m.RecalculateBounds();
    return m;
}

Note that “aAngle” would also be half your FOV angle. “aDistance” defines how far you want to draw the cone. Note it’s the side length of the cone, not its height. The “aConeResolution” defines how many points the cone should have. The more points the smoother the cone base, Also note that the cone is not “closed” at the end. So the “base circle” is missing.

The cone mesh is aligned with the local forward axis. So as long as the FOV angle doesn’t change you only need to create the cone mesh once. If you add the renderer to the enemy it will always show it’s FOV.