Making Field of view using Raycasts With for loops (Using Unity C#)

Question

Code:

        void IdleState ()
    {
    RaycastHit hit;

    for (float i = -ViewWidth; i < ViewWidth; i++)
        { 
            float Iterater = i/20;
            if (Physics.Raycast(transform.position, transform.forward + new Vector3(Iterater,0,0), out hit, ViewRange))
             {
                Debug.DrawRay(transform.position,(transform.forward + new Vector3(Iterater,0,0)).normalized * ViewRange, Color.red);
                if (hit.transform.gameObject.layer == LayerMask.NameToLayer("Player"))
                 {
                    FoundPlayer(hit.transform);
                 }
             }
        }

}

Problem: In Unity I am trying to create a Field of view for an enemy AI by drawing multiple raycasts with for loops. For some reason the raycasts do this: GIF

I've been trying to fix this for days Please help!

Also the FoundPlayer() function in case you need it:

void FoundPlayer  (Transform DetectedObject)
    { 
        float step = TurnSpeed * Time.deltaTime;
        Vector3 Direc = DetectedObject.position - transform.position;
        Vector3 RotMath = Vector3.RotateTowards(transform.forward, Direc,step,0.0f);
        transform.rotation = Quaternion.LookRotation(RotMath);
        Vector3 CurrentRot = transform.eulerAngles;
        transform.rotation = Quaternion.Euler(0,CurrentRot.y,0);
    }

The FoundPlayer() function just rotates the enemy towards the player when one of the raycasts hit it.

Do they need to be rays, or are you just trying to find anything "in view"? — Immersive, Jan 09 '19 at 04:09

Immersive · Accepted Answer · 2019-01-09T04:32:45.553

Regarding Raycast:

transform.Forward is in world-space coordinates, to which you add some fraction of world-space X-axis offset. What you wanted is to add some fraction of 'local-space' X-axis. transform.Right is the world-space conversion of local-space X-axis. Try:

var rayDirection = (transform.Forward + (Vector3.Scale(transform.Right, new Vector3(Iterater, 0, 0))).normalized;

Regarding Fields of View:

If all you want to do is check what objects are within a FOV, start finding everything within a sphere, then filter those objects to what's within appropriate angles from transform.forward:

float ViewRange = 10;
float hHalfFov = 45; // Horizontal Half-Field of View (Degrees)
float vHalfFov = 45; // Vertical Half-Field of View (Degrees)

void IdleState() {

    // Find all colliders within ViewRange
    var hits = Physics.OverlapSphere(transform.position, ViewRange);

    foreach (var hit in hits) {
        if ( hit.gameObject == this.gameObject ) continue; // don't hit self

        // Check FOV
        var direction = (transform.position - hit.transform.position);
        var hDirn = Vector3.ProjectOnPlane(direction, transform.up).normalized; // Project onto transform-relative XY plane to check hFov
        var vDirn = Vector3.ProjectOnPlane(direction, transform.right).normalized; // Project onto transform-relative YZ plane to check vFov

        var hOffset = Vector3.Dot(hDirn, transform.forward) * Mathf.Rad2Deg; // Calculate horizontal angular offset in Degrees
        var vOffset = Vector3.Dot(vDirn, transform.forward) * Mathf.Rad2Deg; // Calculate vertical angular offset in Degrees

        if (hOffset > hHalfFov || vOffset > vHalfFov) continue; // Outside of FOV

        Debug.DrawLine(transform.position, hit.transform.position, Color.red);

        if (hit.transform.gameObject.layer == LayerMask.NameToLayer("Player")) {
            FoundPlayer(hit.transform);
        }
    }
}

It seems that Transform.Scale doesnt exist, neither does transform.scale, was there something else you meant? — William L, Jan 09 '19 at 03:42
So for the most part that worked, only problem is it removed almost all the raycasts, only leaving the 2 on the very edge of the Enemy's Field of view and one that follows the player when detected. — William L, Jan 09 '19 at 03:58
Try different divisors for the Iterater. Consider that you're doing vector additions for the `rayDirection`: One unit forward plus some fraction of one unit left/right. A 45degree offset would require a full unit of offset left/right. Vector addition may not be the best solution, vector rotations would probably be better. The point of this answer was to highlight that you were incorrectly using mixed coordinate systems. — Immersive, Jan 09 '19 at 04:06

Making Field of view using Raycasts With for loops (Using Unity C#)

1 Answers1