我將如何限制LineRender從游戲物件到我的游標的距離？

我正在創建一個迷你高爾夫游戲，玩家可以點擊并拖動來擊球。目前，我有一條線可以顯示出球的方向和力量。我不太確定如何在保持正確方向的同時限制線條渲染的距離（也就是功率）。我還想將線條渲染的長度與圖片左下角的功率計 ui 同步。我在下面提供了我的代碼：

private void ProcessAim()
{
    if (!isAiming || !isIdle) {
        return;
    }        
    
    worldPoint = CastMouseClickRay();
    if (!worldPoint.HasValue) {return;}

    DrawLine(worldPoint.Value);
}

private void Shoot(Vector3 worldPoint)
{
    // Disabling the aiming
    isAiming = false;
    lineRenderer.enabled = false;

    Vector3 horizontalWorldPoint = new Vector3(worldPoint.x, transform.position.y, worldPoint.z);

    Vector3 direction = (horizontalWorldPoint - transform.position).normalized;
    float strength = Vector3.Distance(transform.position, horizontalWorldPoint);
    rb.AddForce(direction * strength * shotPower);
}

private void DrawLine(Vector3 worldPoint) 
{
    Vector3[] positions = { transform.position, worldPoint };

    lineRenderer.SetPositions(positions);
    lineRenderer.enabled = true;
}

private Vector3? CastMouseClickRay()
{
    // Grabs the x and y coords and the clipPlane of the camera
    Vector3 screenMousePosFar = new Vector3(Input.mousePosition.x, Input.mousePosition.y, Camera.main.farClipPlane);
    Vector3 screenMousePosNear = new Vector3(Input.mousePosition.x, Input.mousePosition.y, Camera.main.nearClipPlane);

    // Converts to in-game
    Vector3 worldMousePosFar = Camera.main.ScreenToWorldPoint(screenMousePosFar);
    Vector3 worldMousePosNear = Camera.main.ScreenToWorldPoint(screenMousePosNear);
    Vector3 direction = (worldMousePosFar - worldMousePosNear).normalized;
    
    // Casting a ray between the two clipPlanes of the camera at the x and y coords to see if it hit any colliders
    RaycastHit hit;
    if (Physics.Raycast(worldMousePosNear, worldMousePosFar - worldMousePosNear, out hit, float.PositiveInfinity)) 
    {
        return hit.point;
    } 
    else 
    {
        return null;
    }
}

uj5u.com熱心網友回復：

你正在尋找Vector3.ClampMagnitude

你可以使用它，例如

private void DrawLine(Vector3 worldPoint) 
{
    // get vector from your position towards worldPoint 
    var delta = worldPoint - transform.position;
    // clamp the distance
    delta = Vector3.ClampMagnitude(delta, YOUR_DESIRED_MAX_DISTANCE);

    // assign back
    worldPoint = transform.position   delta;

    Vector3[] positions = { transform.position, worldPoint };

    lineRenderer.SetPositions(positions);
    lineRenderer.enabled = true;
}

順便說一句，CastMouseClickRay你應該簡單地使用Camera.ScreenPointToRay

// you should cache Camera.main!
private Camera mainCamera;

private Vector3? CastMouseClickRay()
{
    // you should cache Camera.main as it is expensive!
    if(!mainCamera) mainCamera = Camera.main;

    // simple as that you get the mouse ray
    var ray = mainCamera.ScreenPointToRay(Input.mousePosition);
    if (Physics.Raycast(ray, out var hit))
    {
        return hit.position;
    }
    else
    {
        return null;
    }
}

或者，如果您真的很想按照您的評論所說的去做

 // Casting a ray between the two clipPlanes of the camera at the x and y coords to see if it hit any colliders

那么你不會使用Raycast無限距離的a，而是使用aPhysics.Linecast

if (Physics.Linecast(worldMousePosNear, worldMousePosFar, out var hit))

如果有任何碰撞器與 start 和 end 之間的線相交，則回傳 true。

標籤：C＃ unity3d 游戏开发

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