[Unity学习]第三人称相机控制脚本

using UnityEngine;

public class ThirdPersonCamera : MonoBehaviour
{
    
    
    public GameObject target; // Target to follow 
    public float targetHeight = 5f; // Vertical offset adjustment 
    public float distance = 12.0f; // Default Distance 
    public float offsetFromWall = 0.1f; // Bring camera away from any colliding objects 
    public float maxDistance = 20f; // Maximum zoom Distance 
    public float minDistance = 0.6f; // Minimum zoom Distance 
    public float xSpeed = 200.0f; // Orbit speed (Left/Right) 
    public float ySpeed = 200.0f; // Orbit speed (Up/Down) 
    public float yMinLimit = -80f; // Looking up limit 
    public float yMaxLimit = 80f; // Looking down limit 
    public float zoomRate = 40f; // Zoom Speed 
    public float rotationDampening = 0.5f; // Auto Rotation speed (higher = faster) 
    public float zoomDampening = 5.0f; // Auto Zoom speed (Higher = faster) 
    public LayerMask collisionLayers = 3841; // What the camera will collide with 
    public bool lockToRearOfTarget = false; // Lock camera to rear of target 
    public bool allowMouseInputX = true; // Allow player to control camera angle on the X axis (Left/Right) 
    public bool allowMouseInputY = true; // Allow player to control camera angle on the Y axis (Up/Down) 

    private float xDeg = 0.0f;
    private float yDeg = 0.0f;
    private float currentDistance;
    private float desiredDistance;
    private float correctedDistance;
    private bool rotateBehind = false;
    private bool mouseSideButton = false;
    private float pbuffer = 0.0f; //Cooldownpuffer for SideButtons 
                                  //private float coolDown = 0.5f; //Cooldowntime for SideButtons  

    void Start()
    {
    
    
        Vector3 angles = transform.eulerAngles;
        xDeg = angles.x;
        yDeg = angles.y;
        currentDistance = distance;
        desiredDistance = distance;
        correctedDistance = distance;

        // Make the rigid body not change rotation 
        //        if (rigidbody)
        //            rigidbody.freezeRotation = true;

        if (lockToRearOfTarget)
            rotateBehind = true;

        //Grab target
        if (target == null)
        {
    
    
            target = GameObject.FindGameObjectWithTag("Player") as GameObject;
        }

        gameObject.layer = 2;
    }

    //Only Move camera after everything else has been updated 
    private void LateUpdate()
    {
    
    
        Apply();
    }

    public void Apply()
    {
    
    
        // Don't do anything if target is not defined 
        if (target == null)
            return;

        //pushbuffer 
        if (pbuffer > 0)
            pbuffer -= Time.deltaTime;
        if (pbuffer < 0)
            pbuffer = 0;

        //Sidebuttonmovement 
        //        if ((Input.GetAxis("Toggle Move") != 0) && (pbuffer == 0))
        //        {
    
    
        //            pbuffer = coolDown;
        //            mouseSideButton = !mouseSideButton;
        //        }

        if (mouseSideButton && Input.GetAxis("Vertical") != 0)
            mouseSideButton = false;

        Vector3 vTargetOffset;

        // If either mouse buttons are down, let the mouse govern camera position 
        if (GUIUtility.hotControl == 0)
        {
    
    
            if (Input.GetMouseButton(0) || Input.GetMouseButton(1))
            {
    
    
                //Check to see if mouse input is allowed on the axis 
                if (allowMouseInputX)
                    xDeg += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
                else
                    RotateBehindTarget();
                if (allowMouseInputY)
                    yDeg -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;

                //Interrupt rotating behind if mouse wants to control rotation 
                if (!lockToRearOfTarget)
                    rotateBehind = false;
            }

            // otherwise, ease behind the target if any of the directional keys are pressed 
            else if (Input.GetAxis("Vertical") != 0 || Input.GetAxis("Horizontal") != 0 || rotateBehind ||
                     mouseSideButton)
            {
    
    
                RotateBehindTarget();
            }
        }

        yDeg = ClampAngle(yDeg, yMinLimit, yMaxLimit);

        // Set camera rotation 
        Quaternion rotation = Quaternion.Euler(yDeg, xDeg, 0);

        // Calculate the desired distance 
        desiredDistance -= Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * zoomRate *
                           Mathf.Abs(desiredDistance);
        desiredDistance = Mathf.Clamp(desiredDistance, minDistance, maxDistance);
        correctedDistance = desiredDistance;

        // Calculate desired camera position 
        vTargetOffset = new Vector3(0, -targetHeight, 0);
        Vector3 position = target.transform.position - (rotation * Vector3.forward * desiredDistance + vTargetOffset);

        // Check for collision using the true target's desired registration point as set by user using height 
        RaycastHit collisionHit;
        Vector3 trueTargetPosition = new Vector3(target.transform.position.x, target.transform.position.y + targetHeight, target.transform.position.z);

        // If there was a collision, correct the camera position and calculate the corrected distance 
        var isCorrected = false;
        if (Physics.Linecast(trueTargetPosition, position, out collisionHit, collisionLayers))
        {
    
    
            // Calculate the distance from the original estimated position to the collision location, 
            // subtracting out a safety "offset" distance from the object we hit.  The offset will help 
            // keep the camera from being right on top of the surface we hit, which usually shows up as 
            // the surface geometry getting partially clipped by the camera's front clipping plane.
            correctedDistance = Vector3.Distance(trueTargetPosition, collisionHit.point) - offsetFromWall;
            isCorrected = true;
        }

        // For smoothing, lerp distance only if either distance wasn't corrected, or correctedDistance is more than currentDistance
        currentDistance = !isCorrected || correctedDistance > currentDistance
            ? Mathf.Lerp(currentDistance, correctedDistance, Time.deltaTime * zoomDampening)
            : correctedDistance;

        // Keep within limits 
        currentDistance = Mathf.Clamp(currentDistance, minDistance, maxDistance);

        // Recalculate position based on the new currentDistance 
        position = target.transform.position - (rotation * Vector3.forward * currentDistance + vTargetOffset);

        //Finally Set rotation and position of camera 
        transform.rotation = rotation;
        transform.position = position;
    }

    private void RotateBehindTarget()
    {
    
    
        float targetRotationAngle = target.transform.eulerAngles.y;
        float currentRotationAngle = transform.eulerAngles.y;
        xDeg = Mathf.LerpAngle(currentRotationAngle, targetRotationAngle, rotationDampening * Time.deltaTime);

        // Stop rotating behind if not completed 
        if (targetRotationAngle == currentRotationAngle)
        {
    
    
            if (!lockToRearOfTarget)
                rotateBehind = false;
        }
        else
            rotateBehind = true;
    }

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