轮流走向最后的轮换挑战

Question

Consider this working script, that handles a FPS camera movement:

using UnityEngine;

public class CameraHandler : MonoBehaviour {
    public Transform target;
    float dragSpeed = 10f;
    float lookAtSensitivity = 200f;
    float xRot;
    Transform parentGO;

    private void Start() {
        parentGO = transform.parent;
    }
    void goToPivot(Transform pivot) {
        parentGO.position = Vector3.Lerp(transform.position, pivot.position, 0.05f);
        transform.rotation = Quaternion.Lerp(transform.rotation, pivot.rotation, 0.05f);
    }

    void resetCamRot() {
        xRot = 0;
        float yRot = transform.localEulerAngles.y;
        parentGO.transform.eulerAngles += new Vector3(0, yRot, 0);
        transform.localEulerAngles -= new Vector3(0, yRot, 0);
    }

    void LateUpdate() {
        if (Input.GetKey(KeyCode.Mouse1)) {  
            float touchX = Input.GetAxis("Mouse X") * lookAtSensitivity * Time.deltaTime;
            float touchY = Input.GetAxis("Mouse Y") * lookAtSensitivity * Time.deltaTime;
            xRot -= touchY;
            xRot = Mathf.Clamp(xRot, -90f, 90f);
            transform.localRotation = Quaternion.Euler(xRot, 0f, 0f);
            parentGO.transform.Rotate(Vector3.up * touchX);
            
        }

        if (Input.GetKey(KeyCode.Space)) {
            goToPivot(target);
        }
        if (Input.GetKeyUp(KeyCode.Space)) {
            resetCamRot();
        }
    }
}

Check how the rotations take place in different gameobjects in their respective axis, so that each of rotations are kept independent and everything works.

transform.localRotation = Quaternion.Euler(xRot, 0f, 0f); //camera GO only rotates in local x
parentGO.transform.Rotate(Vector3.up * touchX); //parent GO only rotates in global y

Problem comes when I need to "force" the camera look a certain direction without the inputs, to the FPS movement rules break, and for example the camera gameobject rotates also in the Y xis. That is why I need to call the resetCamRot() method, and traspass the local rotation from the camera object to the parent so that the situation meets the the FPS movement requirements (no local Y axis rotation).

Without calling the resetCamRot() method, when the FPS movement starts on right mouse button click, the camera abruptly changes to the direction it was facing before "forcing" it with goToPivot that sets the position and the rotation.(Just commentinf the resetCamRot method out)

Although resetCamRot() does the work it feels a bit hacky, so is there another way to set the camera to a forced rotation maintaining the local rotation of the child object (where the camera is) to 0?

I thought of decomposing the next step rotation given by Quaternion.Lerp(transform.rotation, pivot.rotation, 0.05f); in the goToPivot() method in each of their respective axis and gameObjects as its done when the rotation is set from the input, to have a clean local Y rot in he camera gameobject each step. Seems to be the over-complicated thing in this case, but was not able to figure that out.

I you wish to try the script out for the challenge just need to add a parent gameobject to the camera and the attach the target in the editor.

Answer 1

This will make the camera look in the direction, the parent transform look in the direction, only flattened, and finally update the internal state ( xRot ) in accordance with the difference between the two:

    void LookTowards(Vector3 direction) {
        Vector3 flattened = direction;
        flattened.y = 0f;

        parentGo.rotation = Quaternion.LookRotation(flattened);
        transform.rotation = Quaternion.LookRotation(direction);
        xRot = Vector3.SignedAngle(flattened, direction, parentGo.right);
    }