Strategy for implementing self driving cars (objects) in Unity 3D. This is very taxing on the CPU as it essentially uses computer vision in the game world sense.

self-driving-car-unity.cs

RaycastHit hit;
bool foundRoad = false;
bool playerIsInFront = false;

Vector3 current = new Vector3(gameObject.transform.position.x, 5, gameObject.transform.position.z);

Vector3 aheadWorld = new Vector3(0, -5, 15);
Vector3 leftWorld = new Vector3(-15, -5, 0);
Vector3 rightWorld = new Vector3(15, -5, 0);
Vector3 behindWorld = new Vector3(0, -5, -15);

Vector3 ahead = gameObject.transform.TransformDirection(aheadWorld);
Vector3 left = gameObject.transform.TransformDirection(leftWorld);
Vector3 right = gameObject.transform.TransformDirection(rightWorld);
Vector3 behind = gameObject.transform.TransformDirection(behindWorld);

Debug.DrawRay(current, ahead);
Debug.DrawRay(current, left);
Debug.DrawRay(current, right);
Debug.DrawRay(current, behind);

// If there is road ahead
if (Physics.Raycast (current, ahead, out hit)) {

  if (hit.collider.gameObject.tag == "Player") {
    playerIsInFront = true;
  } else {
    if (!foundRoad && isRoad (hit.collider.gameObject)) {
      transform.LookAt (hit.collider.gameObject.transform.position);
      foundRoad = true;
    }
  }
}

// If there is road to the left
if (Physics.Raycast (current, left, out hit)) {
  if (!playerIsInFront && !foundRoad && isRoad (hit.collider.gameObject)) {
    transform.LookAt(hit.collider.gameObject.transform.position);
    foundRoad = true;
  }
}

// If there is road to the right
if (Physics.Raycast (current, right, out hit)) {
  if (!foundRoad && isRoad (hit.collider.gameObject)) {
    transform.LookAt(hit.collider.gameObject.transform.position);
    foundRoad = true;
  }
}

// If there is road behind
if (Physics.Raycast (current, behind, out hit)) {
  if (!foundRoad && isRoad (hit.collider.gameObject)) {
    transform.LookAt(hit.collider.gameObject.transform.position);
    foundRoad = true;
  }
}

// Look at the road
if (foundRoad && !playerIsInFront) {
  if (!gm.paused) {
    gameObject.transform.position += gameObject.transform.TransformDirection (Vector3.forward) * 5.0f * Time.deltaTime;
  }
}

if (!foundRoad) {
  gm.deleteObject (gameObject);
  gm.createRandomCar ();
}



private bool isRoad(GameObject g) {   
if (g.tag == "Road") {
  return true;
} else {
  return false;
}
}