![追踪四种方法](https://img-blog.csdn.net/20170804171949060?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
追踪过程中会发射一条射线,这条射线是会穿过物体的,并能够记录穿过的物体。可以做瞄准器,做跟踪人物用。
交互计算
![交互计算方式](https://img-blog.csdn.net/20170805095339111?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
计算的演示
![这里写图片描述](https://img-blog.csdn.net/20170805095518535?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
示例
1. 以第三人称模板为例
![这里写图片描述](https://img-blog.csdn.net/20170805104123292?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
2. 效果如图
![这里写图片描述](https://img-blog.csdn.net/20170805104434643?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
射线穿过物体的时候颜色会改变。因为当前是单通的,一次只能检测到一个物体。
3. LineByChannel 和LineTraceForObjects的区别
![这里写图片描述](https://img-blog.csdn.net/20170805105528597?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
LineTraceForObjects 可以传入待检测的类型,就是只检测这个类型的物体
![这里写图片描述](https://img-blog.csdn.net/20170805105607581?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
下面是一次检测多个物体的代码示例
![这里写图片描述](https://img-blog.csdn.net/20170805111834442?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
以上这段代码在实际应用中没有效果,建议使用MultiLineTraceForObject,这个是正常的。
Demo
1. 新建一个关卡,TranInteraction
2. 创建一个Pawn蓝图类-BP_TraceInteractionPawn,接口BPI_TrancInteraction
3. 创建一个SceneComponent组件-BPC_TraceInteraction
创建7个接口函数
1. TraceHitObject(Hit Result Hit); 返回值的名字为Bool Return
2. TraceLeaveObject(Hit Result Hit); 返回值的名字为Bool Return
3. TraceHitComponent(Hit Result Hit,PrimitiveComponent Component); 返回值的名字为Bool Return
4. TraceLeaveComponent(Hit Result Hit,PrimitiveComponent Component); 返回值的名字为Bool Return
5. TraceMove(Hit Result Hit(勾选引用传递)); 返回值的名字为Bool Return
6. TraceActivateDown(Hit Result Hit,Pawn Instigator); 返回值的名字为Bool Return
7. TraceActivateUp(Hit Result Hit,Pawn Instigator); 返回值的名字为Bool Return
1. 打开BPC_TraceInterface
2. 新建两个函数,LineTrace(float Distance) 返回值HitResult Hit,InteractWithHit(HitResult Hit)
3. 新建变量,Actor FocusedObject,PrimitiveComponent FocusedComponent,HitResult CurrentHit(私有的),局部变量(HitResult InHit)
4.
![这里写图片描述](https://img-blog.csdn.net/20170805125103111?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
5.把HitActor,HitComponent提升为局部变量
![这里写图片描述](https://img-blog.csdn.net/20170805125604495?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbG9uZ3lhbmJ1aHVp/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)