获取鼠标位置下的UGUI或3D物体

来自于：剑起苍穹
根据UGUI的射线检测机制获取当前鼠标下的UI

/// <summary>
/// 获取鼠标停留处UI
/// </summary>
/// <param name="canvas"></param>
/// <returns></returns>
public GameObject GetOverUIobj(GameObject canvas)
{
    PointerEventData pointerEventData = new PointerEventData(EventSystem.current);
    pointerEventData.position = Input.mousePosition;
    GraphicRaycaster gr = canvas.GetComponent<GraphicRaycaster>();
    List<RaycastResult> results = new List<RaycastResult>();
    gr.Raycast(pointerEventData, results);
    if (results.Count != 0)
    {
        return results[0].gameObject;
    }
    return null;
}

不仅适用于UGUI，也可以在摄像机上添加PhysicsRaycaster组件，这样可以获取3D物体。

/// <summary>
/// 获取鼠标停留处物体
/// </summary>
/// <param name="raycaster"></param>
/// <returns></returns>
public GameObject GetOverWordGameObject(GameObject raycaster)
{
    PointerEventData pointerEventData = new PointerEventData(EventSystem.current);
    pointerEventData.position = Input.mousePosition;
    PhysicsRaycaster pr = raycaster.GetComponent<PhysicsRaycaster>();
    List<RaycastResult> results = new List<RaycastResult>();
    pr.Raycast(pointerEventData, results);
    if (results.Count != 0)
    {
        return results[0].gameObject;
    }
    return null;
}