二维角色精灵 animation 与 3D 等距旋转相机？

Question

Im trying to write a script to control my players sprite animations that adjusts direction when the camera is rotated. It is a 2D sprite in a 3D isometric world with fixed cameras for each direction. Right now I have three separate scripts for player controller, player animation and sprite renderer.

Player Controller:

public class PlayerController : MonoBehaviour
{
    public float speed = 5f;
    
void Update()
    {
        var moveInput = new Vector3(Input.GetAxis("Horizontal"), 0f , Input.GetAxis("Vertical"));

        moveInput = Camera.main.transform.TransformDirection(moveInput);
        moveInput.y = 0;
        moveInput = moveInput.normalized;
    
        transform.position += moveInput * Time.deltaTime * speed;
    }
}

The controller is based off the cameras direction because multiple cameras are used for each direction.

Player Animation:

public class PlayerAnimation : MonoBehaviour

{
    public Rigidbody2D body;
    public SpriteRenderer spriteRenderer;
    public List<Sprite> nSprite;
    public List<Sprite> neSprite;
    public List<Sprite> eSprite;
    public List<Sprite> seSprite;
    public List<Sprite> sSprite;
    public float frameRate;
    float idleTime;
    Vector3 direction;
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        direction = new Vector3(Input.GetAxis("Horizontal"), 0f , Input.GetAxis("Vertical")).normalized;
        
        direction = Camera.main.transform.TransformDirection(direction);

        HandleSpriteFlip();

        List<Sprite> directionSprites = GetSpriteDirection();

        if(directionSprites != null) //holding direction
        {
            float playTime = Time.time - idleTime; //time since we sterted walking
            int totalFrames = (int)(playTime * frameRate); //total frames since we started
            int frame =  totalFrames % directionSprites.Count; //current frame

            spriteRenderer.sprite = directionSprites[frame];
        }
        else //holding nothing, input is neutral
        {
            idleTime = Time.time;
        }
    }

    void HandleSpriteFlip()
    {
        if (!spriteRenderer.flipX && direction.x < 0)
        {
            spriteRenderer.flipX = true;
        }
        else if (spriteRenderer.flipX && direction.x > 0)
        {
            spriteRenderer.flipX = false;
        }
    }

    List<Sprite> GetSpriteDirection()
    {

        List<Sprite> selectedSprites = null;

        if (direction.y > 0) //north
        {
            if (Mathf.Abs(direction.x) > 0) //east or west
            {
                selectedSprites = neSprite;
            }
            else {//neutral
                selectedSprites = nSprite;
            }
        }
        else if (direction.y < 0) //south
        {
            if (Mathf.Abs(direction.x) > 0) //east or west
            {
                selectedSprites = seSprite;
            }
            else {//neutral
                selectedSprites = sSprite;
            }
        }
        else //neutral
        {
            if (Mathf.Abs(direction.x) > 0) //east or west
            {
                selectedSprites = eSprite;
            }
        }

        return selectedSprites;
    }
}

This player animation script that I was following made a lot of since to me but it was written with a 2D controller. How should I add the walk animations, can it tracks the players current facing direction to update the sprite renderer?

Sprite Renderer:

private SpriteRenderer spriteRenderer;

public Transform plane;
public Camera cam;

private const float step = 22.5f;

public Sprite N, NW, W, SW, S, SE, E, NE;
public void Start() => spriteRenderer = GetComponent<SpriteRenderer>();
public void Update()
{
    var projected = Vector3.ProjectOnPlane(cam.transform.forward, plane.up);
    var angle = Vector3.SignedAngle(projected, plane.forward, plane.up);
    
    var AbsAngle = Mathf.Abs(angle);
    
    if (AbsAngle < step) spriteRenderer.sprite = N;
    else if (AbsAngle < step*3) spriteRenderer.sprite = Mathf.Sign(angle) < 0 ? NW : NE;
    else if (AbsAngle < step*5) spriteRenderer.sprite = Mathf.Sign(angle) < 0 ? W : E;
    else if (AbsAngle < step*7) spriteRenderer.sprite = Mathf.Sign(angle) < 0 ? SW : SE;
    else spriteRenderer.sprite = S;
    
    Billboard(spriteRenderer.transform, cam);
}
public void Billboard(Transform character, Camera mainCamera)
{
    var dir = plane.position - mainCamera.transform.position;
    var LookAtRotation = Quaternion.LookRotation(dir);
    
    var LookAtRotationOnly_Y = Quaternion.Euler(character.rotation.eulerAngles.x, LookAtRotation.eulerAngles.y,character.eulerAngles.z);
    character.rotation = LookAtRotationOnly_Y;
}

This is from the question commented below and it works to update the camera on a stationary object, but how would i use it for a moving player that changes facing direction.

Answer 1

To solve this problem, I propose a special technique here. All you have to do is replace the sprites with sprite animations. It does take a bit of patience though. First you have to create motion animations as well as idle in all directions as below and then make sure the animation is executed with the play key.

After doing this you need an animator. But not like the old days when you connected them with a transition. There are 4 directions below, you can enter all 16 states in the animator as below and set the default to none without any animation. The purpose of this animator is only to store animations. Changes will be made by the script. We only need the names of the states, carefully follow the string codes and name them as follows.

Animation string codes :

• for Move : "move" + "{direction key}"
• for Idle : "idle" + "{direction key}"

After performing the above steps, it's time to actually change states instead of changing sprites. To do this, we no longer need to have the SpriteRenderer component, instead we get the Animator .

public Animator animator;

public void Start() => animator = GetComponent<Animator>(); //

In the continuation of the program, instead of changing the sprite in different directions, you should change the states according to the direction of the character. here we have a stateName variable that chooses which state to play at the end of the code. If you change the forward character through the movement code, here it is enough to select the speed of movement to select "idle" or "move" , then the direction extension is connected to the name state and the desired animation will be executed.

// this is condition of choosing between idle or move, you can get direction vector like before

var stateName = GetDirection().magnitude != 0 ? "move" : "idle"; 

if (AbsAngle < step) stateName += "N";
else if (AbsAngle < step*3) stateName += Mathf.Sign(angle) < 0 ? "NW" : "NE";
else if (AbsAngle < step*5) stateName += Mathf.Sign(angle) < 0 ? "W" : "E";
else if (AbsAngle < step*7) stateName += Mathf.Sign(angle) < 0 ? "SW" : "SE";
else stateName += "S";

if (!animator.GetCurrentAnimatorStateInfo(0).IsName(stateName)) animator.Play(stateName);

public Vector3 GetDirection() => new Vector3(Input.GetAxis("Horizontal"), 0f , Input.GetAxis("Vertical")).normalized;