Unity 2D和3D对象的点击
发表于2018-11-09
这篇文章给大家分别介绍下如何判断2D和3D对象的点击，想了解2D和3D对象的点击有何不同就来看看吧。
1、2D对象响应点击
（1）Canvas对象上有Graphic Raycaster
（2）被点击的对象加上Image，并勾选Raycast Target
（3）场景里有唯一对象挂上EventSystem和StandaloneInputModule
（4）被点击的对象加上Button，然后调用：
GetComponent<Button>().onClick.AddListener(() =>
｛
Debug.Log("button click");
｝);
2、3D对象响应点击
（1）看3d对象的camera上挂上Physics Raycaster
（2）被点击对象上加上Box Collider
（3）场景里有唯一对象挂上EventSystem和StandaloneInputModule
（4）挂上点击脚本，内容如下：
public class SceneObjClick : EventTrigger ｛
public override void OnPointerClick(PointerEventData eventData)
｛
base.OnPointerClick(eventData);
Debug.Log("Scene Obj Click");
｝
public override void OnDrag(PointerEventData eventData)
｛
base.OnDrag(eventData);
Debug.Log("Scene Obj Drag");
｝
｝
其中EventTrigger.cs是unity自身的脚本，内如如下：
namespace UnityEngine.EventSystems
｛
//
// 摘要:
// ///
// Receives events from the EventSystem and calls registered functions for each
// event.
// ///
[AddComponentMenu("Event/Event Trigger")]
public class EventTrigger : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler, IPointerDownHandler, IPointerUpHandler, IPointerClickHandler, IInitializePotentialDragHandler, IBeginDragHandler, IDragHandler, IEndDragHandler, IDropHandler, IScrollHandler, IUpdateSelectedHandler, ISelectHandler, IDeselectHandler, IMoveHandler, ISubmitHandler, ICancelHandler, IEventSystemHandler
｛
//
// 摘要:
// ///
// All the functions registered in this EventTrigger (deprecated).
// ///
[Obsolete("Please use triggers instead (UnityUpgradable) -> triggers", true)]
public List<Entry> delegates;
protected EventTrigger();
//
// 摘要:
// ///
// All the functions registered in this EventTrigger.
// ///
public List<Entry> triggers ｛ get; set; ｝
//
// 摘要:
// ///
// Called before a drag is started.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnBeginDrag(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a Cancel event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnCancel(BaseEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a new object is being selected.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnDeselect(BaseEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem every time the pointer is moved during dragging.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnDrag(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when an object accepts a drop.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnDrop(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem once dragging ends.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnEndDrag(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a drag has been found, but before it is valid
// to begin the drag.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnInitializePotentialDrag(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a Move event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnMove(AxisEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a Click event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnPointerClick(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a PointerDown event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnPointerDown(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when the pointer enters the object associated with
// this EventTrigger.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnPointerEnter(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when the pointer exits the object associated with this
// EventTrigger.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnPointerExit(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a PointerUp event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnPointerUp(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a Scroll event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnScroll(PointerEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a Select event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnSelect(BaseEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when a Submit event occurs.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnSubmit(BaseEventData eventData);
//
// 摘要:
// ///
// Called by the EventSystem when the object associated with this EventTrigger is
// updated.
// ///
//
// 参数:
// eventData:
// Current event data.
public virtual void OnUpdateSelected(BaseEventData eventData);
//
// 摘要:
// ///
// An Entry in the EventSystem delegates list.
// ///
public class Entry
｛
//
// 摘要:
// ///
// The desired TriggerEvent to be Invoked.
// ///
public TriggerEvent callback;
//
// 摘要:
// ///
// What type of event is the associated callback listening for.
// ///
public EventTriggerType eventID;
public Entry();
｝
//
// 摘要:
// ///
// UnityEvent class for Triggers.
// ///
public class TriggerEvent : UnityEvent<BaseEventData>
｛
public TriggerEvent();
｝
｝
｝
3、点击原理
底层调用Physics.RaycastAll，从摄像机发出一条射线，拿到所有碰撞到的物体，进行排序，获取第一个碰撞物体，然后获取该物体上得事件函数，进行调用。事件函数有EventTrigger继承的那些接口。