Line-by-line explanation:
Lines 1-4: Declare the PlayerController class, which inherits from the MonoBehaviour class. Lines 6-8: Declare public variables for the player's speed, mouse sensitivity, and jump height. Lines 11-13: Declare private variables for the player's forward/backward and left/right movement values, as well as their rotation around the x- and y-axes. Lines 16-17: Declare private variables for the player's movement vector and Rigidbody component. Line 19: In the Start() method, get the Rigidbody component attached to the GameObject and store it in the rb variable. Lines 22-35: In the Update() method, calculate the player's movement vector based on their input. Then, use the Rigidbody component to apply forces to the player and move them around. Lines 37-39: Rotate the player around the x-axis based on their mouse input. Lines 41-43: Rotate the camera around the y-axis based on the player's mouse input. Lines 45-47: If the player presses the space bar, jump. The camera can rotate freely around the y-axis, without any limits. This may make the player controller more difficult to control, especially if the player is using a high mouse sensitivity. It is important to test the player controller and adjust the mouse sensitivity as needed to find a setting that is comfortable and controllable for the player.