ml-agents/Project/Assets/ML-Agents/Examples/Dodgeball/Scripts/MouseLook.cs

using UnityEngine;
using System.Collections;

// Script by IJM: http://answers.unity3d.com/questions/29741/mouse-look-script.html
// Changed to fit standard C# conventions

// MouseLook rotates the transform based on the mouse delta.
// Minimum and Maximum values can be used to constrain the possible rotation

// To make an FPS style character:
// - Create a capsule.
// - Add a rigid body to the capsule
// - Add the MouseLook script to the capsule.
// -> Set the mouse look to use LookX. (You want to only turn character but not tilt it)
// - Add FPSWalker script to the capsule

/// - Create a camera. Make the camera a child of the capsule. Reset it's transform.
/// - Add a MouseLook script to the camera.
/// -> Set the mouse look to use LookY. (You want the camera to tilt up and down like a head. The character already turns.)
[AddComponentMenu("Camera-Control/Mouse Look")]
public class MouseLook : MonoBehaviour {

	public enum RotationAxes { MouseXAndY = 0, MouseX = 1, 	MouseY = 2 };
	public RotationAxes axes = RotationAxes.MouseXAndY;
	public float sensitivityX = 15F;
	public float sensitivityY = 15F;

	public float minimumX = -360F;
	public float maximumX = 360F;

	public float minimumY = -60F;
	public float maximumY = 60F;

	float rotationX = 0F;
	float rotationY = 0F;

	Quaternion originalRotation;

	void FixedUpdate()
	{
		if (axes == RotationAxes.MouseXAndY)
		{
			// Read the mouse input axis
			rotationX += Input.GetAxis("Mouse X") * sensitivityX;
			rotationY += Input.GetAxis("Mouse Y") * sensitivityY;

			rotationX = ClampAngle(rotationX, minimumX, maximumX);
			rotationY = ClampAngle(rotationY, minimumY, maximumY);

			Quaternion xQuaternion = Quaternion.AngleAxis(rotationX, Vector3.up);
			Quaternion yQuaternion = Quaternion.AngleAxis(rotationY, -Vector3.right);

			transform.localRotation = originalRotation * xQuaternion * yQuaternion;
		}
		else if (axes == RotationAxes.MouseX)
		{
			rotationX += Input.GetAxis("Mouse X") * sensitivityX;
			rotationX = ClampAngle(rotationX, minimumX, maximumX);

			Quaternion xQuaternion = Quaternion.AngleAxis(rotationX, Vector3.up);
			transform.localRotation = originalRotation * xQuaternion;
		}
		else
		{
			rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
			rotationY = ClampAngle(rotationY, minimumY, maximumY);

			Quaternion yQuaternion = Quaternion.AngleAxis(-rotationY, Vector3.right);
			transform.localRotation = originalRotation * yQuaternion;
		}
	}

	void Start()
	{
		originalRotation = transform.localRotation;
	}

	public static float ClampAngle(float angle, float min, float max)
	{
		if (angle < -360F)
			angle += 360F;
		if (angle > 360F)
			angle -= 360F;
		return Mathf.Clamp(angle, min, max);
	}
}