Object Visibiliy Check

using UnityEngine;

public static class VisibilityHelper
{
    private static float DistantRadiusToAngle(float distance, float radius)
    {
        return Mathf.Asin(radius / distance) * Mathf.Rad2Deg;
    }

    public static bool IsObjetVisible(Vector2 viewPosition, Vector2 viewDirection, float viewDistance, float viewAngle, Vector2 objectPosition, float objectRadius)
    {
        Vector2 delta = objectPosition - viewPosition;
        float distanceToObject = delta.magnitude;

        //If view circle and object circle do not intersect - then object is out of view range
        if (viewDistance + objectRadius < distanceToObject)
            return false;

        float angleToObject = Vector2.Angle(viewDirection, delta);

        //Since out calculations are using decline from view direction - we need only half of our view angle
        float halfViewAngle = viewAngle / 2f;
        //We are converting object radius to angle, using trigonomentry
        float objectRadiusAsAngle = DistantRadiusToAngle(distanceToObject, objectRadius);

        //If object is declined too far from our view direction - then it is outside of our viewport
        if ((halfViewAngle + objectRadiusAsAngle) < angleToObject)
            return false;

        return true;
    }
}