Camera not displaying anything when clamped used to set restrictions in Unity - unity3d

Question

Good day
I am trying to restrict my camera movement using a function that I am using to restrict other elements in a 2D game. When I call this function using my camera, it does something strange.
For some reason it does not display anything as soon as I called the function. I have tested the camera's position using Debug.log, and it seems to be in exactly the same place. The constraints also seem to work, but that is useless if nothing displays.
I am using a Mathf.Clamp function to try and constrain the map. I know that there are many tutorials showing how to constrain map movement, and honestly my approach seems similar.
I want to know why this function is failing. I am trying to keep things generic, and am already using this function to restrict the movement of other game elements.
My code looks like this:
int cameraSpeed = 10;
GameObject camera;
int maxX = 20;
int minX = -20;
int maxY = 20;
int minY = -20;
// Use this for initialization
public void constrain(GameObject obj)
{
Vector2 pos = obj.transform.position;
pos.x = Mathf.Clamp(pos.x, -maxX, maxX);
pos.y = Mathf.Clamp(pos.y, -maxY, maxY);
obj.transform.position = pos;
}
void Start () {
camera = GameObject.Find("Main Camera");
}
// Update is called once per frame
void Update()
{
if (Input.GetKey(KeyCode.RightArrow))
{
camera.transform.Translate(new Vector2(cameraSpeed * Time.deltaTime, 0));
}
if (Input.GetKey(KeyCode.LeftArrow))
{
camera.transform.Translate(new Vector2(-cameraSpeed * Time.deltaTime, 0));
}
if (Input.GetKey(KeyCode.DownArrow))
{
camera.transform.Translate(new Vector2(0, -cameraSpeed * Time.deltaTime));
}
if (Input.GetKey(KeyCode.UpArrow))
{
camera.transform.Translate(new Vector2(0, cameraSpeed * Time.deltaTime));
}
Debug.Log(camera.transform.position.x);
Debug.Log(camera.transform.position.y);
constrain(camera);
}
Screenshot of game without constraints:
Screenshot of game with constraints:
I am new to Unity and am trying to understand it thoroughly. Any advice would be greatly appropriated.

Answer 1

The Z-position of your camera is being set to 0. All of your other objects have the same Z-position, so the camera won't render them.
Change constrain() to:
public float zPos = -10
public void constrain(GameObject obj)
{
Vector3 pos = obj.transform.position;
pos.x = Mathf.Clamp(pos.x, -maxX, maxX);
pos.y = Mathf.Clamp(pos.y, -maxY, maxY);
pos.z = zPos
obj.transform.position = pos;
}
and that should fix it.
EDIT: The reason that this is happening is because you were using a Vector2 for your camera position. In Unity, a Vector2 is a Vector3 with a z-value of 0.

Answer 2

I have managed to find the bug with #DerwB's assistance. I now see that the camera needs to be on a lower z index than the objects it is displaying. DerwB's answer is close to a solution, but it does not allow the function to be reused to constrain other objects.
I have thus modified the function as below:
public void constrain(GameObject obj, bool isCamera = false)
{
Vector3 pos = obj.transform.position;
pos.x = Mathf.Clamp(pos.x, -maxX, maxX);
pos.y = Mathf.Clamp(pos.y, -maxY, maxY);
if(isCamera)
pos.z = 0;
else
pos.z = 1;
obj.transform.position = pos;
}
You then call the function as follows for the camera:
GameObject camera = GameObject.Find("Main Camera");
constrain(camera.gameObject,true); //if you are constraining the camera object
And like this if you are referencing other game objects:
GameObject player= GameObject.Find("Player");
constrain(player.gameObject,true); //skip the optional parameter if not referencing the camera