using UnityEngine;

public class Camera_FPS : MonoBehaviour
{
public Vector2 rotationLimit; //Limit for the vertical rotation of the camera. X is higher limit, Y is lower limit.
public float rotationSpeed = 600.0f; //Vertical rotation speed of the camera
public bool invertY = true; //Invert vertical rotation
public bool headBobEnabled = true; //Enables/disables head bobbing
public Vector2 headBobDistance = new Vector2(0.2f, 0.3f); //The distance the camera travels in the y-axis for the headBobbing effect
public float headBobSpeed = 5.0f; //Speed at which the player's head bobs

private Vector3 initialLocalPos; //Starting local y-position of camera
private float rot; //Stores the rotation value incremented by mouse movement in the y-axis
private Transform t; //Reference to the transform component of the game object

public void Awake()
{
t = transform; //Cache transform component
initialLocalPos = t.localPosition; //Store initial local position of the camera
}

public void Update ()
{
//Update rotation
rot += Input.GetAxis("Mouse Y") * rotationSpeed * ((invertY) ? -1 : 1) * Time.deltaTime;
if(rot < rotationLimit.y) //Check for lower limit
rot = rotationLimit.y;
if(rot > rotationLimit.x) //Check for upper limi
rot = rotationLimit.x;
t.localRotation = Quaternion.AngleAxis (rot, Vector3.right); //Apply rotation to transform

//Head bobbing
if(headBobEnabled)
{
//Calculate percentage of blend between stationary and bobbing camera positions
float percentage = Mathf.Min(1, Mathf.Abs(Input.GetAxis("Vertical")) + Mathf.Abs(Input.GetAxis("Horizontal")));

//Calculate desired x position
float desiredPosX = initialLocalPos.x + headBobDistance.x * Mathf.Sin(Time.time * headBobSpeed + Mathf.PI/2);
//Blend between stationary and desired x position
float newX = (initialLocalPos.x * (1 - percentage)) + (desiredPosX * (percentage));

//Calculate desired y position
float desiredPosY = initialLocalPos.y + headBobDistance.y * Mathf.Sin(Time.time * 2 * headBobSpeed);
//Blend between stationary and desired y position
float newY = (initialLocalPos.y * (1 - percentage)) + (desiredPosY * (percentage));

t.localPosition = new Vector3( newX, newY, t.localPosition.z);
}
}
}