UE4 重叠和碰撞事件的相应

在UE4刚开始学习碰撞检测的时候，发现重叠事件和碰撞相应函数无法调用，经过自己反复实验，找到了一些机制，现在记录下来。

1. 首先定义一个Actor用来检测重叠事件和碰撞事件

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "OverlapActor.generated.h"

UCLASS()
class TRACELENGTH_API AOverlapActor : public AActor {
	GENERATED_BODY()

public:
	// Sets default values for this actor's properties
	AOverlapActor();

	UPROPERTY(VisibleAnywhere, Category = "Pickup")
	class UStaticMeshComponent* PickupMesh;
	UPROPERTY(VisibleAnywhere, Category = "Pickup")
	class UBoxComponent* OverlapBox;
protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:
	// Called every frame
	virtual void Tick(float DeltaTime) override;
	UFUNCTION()
	void BeginOverlap(UPrimitiveComponent*OverlappedComponent, AActor* OtherActor, UPrimitiveComponent*OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);
	UFUNCTION() 
	void EndOverlap(UPrimitiveComponent*OverlappedComponent, AActor* OtherActor, UPrimitiveComponent*OtherComp, int32 OtherBodyIndex);

	UFUNCTION()
	void ComponentHit(UPrimitiveComponent* HitComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit);

};

// Fill out your copyright notice in the Description page of Project Settings.


#include "OverlapActor.h"
#include "Components/StaticMeshComponent.h"
#include "Components/BoxComponent.h"


// Sets default values
AOverlapActor::AOverlapActor() {
	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

	PickupMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("PickupMesh"));
	SetRootComponent(PickupMesh);

	OverlapBox = CreateDefaultSubobject<UBoxComponent>(TEXT("OverlapBox"));
	OverlapBox->SetupAttachment(GetRootComponent());

}

// Called when the game starts or when spawned
void AOverlapActor::BeginPlay() {
	Super::BeginPlay();
	OverlapBox->OnComponentBeginOverlap.AddDynamic(this, &AOverlapActor::BeginOverlap);
	OverlapBox->OnComponentEndOverlap.AddDynamic(this, &AOverlapActor::EndOverlap);

	PickupMesh->OnComponentHit.AddDynamic(this,	&AOverlapActor::ComponentHit);
}

// Called every frame
void AOverlapActor::Tick(float DeltaTime) {
	Super::Tick(DeltaTime);

}

void AOverlapActor::BeginOverlap(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult) {
	UE_LOG(LogTemp, Warning, TEXT("BeginOverlap"));
}

void AOverlapActor::EndOverlap(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex) {
	UE_LOG(LogTemp, Warning, TEXT("EndOverlap"));
}

void AOverlapActor::ComponentHit(UPrimitiveComponent* HitComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit) {
	UE_LOG(LogTemp, Warning, TEXT("ComponentHit"));
}

对应的蓝图如下：

2. 设置场景
在场景中仿真这个Actor,并且放置一个立方体Cube2在它的正上方，用来检测重叠和碰撞事件

3. 检测重叠事件
3.1. 勾选Cube2 ，【细节面板】->【物理】->【模拟物理】和【启用重力】

3.2. 勾选 Cube2【碰撞】->【生产重叠事件】

3.3. 勾选BP_OverlapActor下的OverlapBox->【生产重叠事件】

这样就可以检测重叠事件了，当运行的时候，上方的立方体掉落下来，日志中就会输出相应的信息

4. 检测碰撞事件
只有勾选向BP_OverlapActor下面的组件PickupMesh->【模拟生产命中事件】

运行日志就会打印出来碰撞日志

3.碰撞检测还有另外一种方法，就是在Actor中实现函数NotifyActorBeginOverlap

当Actor与另外一个Actor触发时的重叠时的触发事件，例如一个玩家走进触发器；当物体阻塞发生碰撞时，撞击墙壁，
注意 bGenerateOverlapEvents 必须为 true;

public:
	void NotifyActorBeginOverlap(AActor* otherActor)override;

void ATestActor::NotifyActorBeginOverlap(AActor* otherActor) {
	Super::NotifyActorBeginOverlap(otherActor);

	AGameCharacter* gameCharacter = Cast<AGameCharacter>(otherActor);
	if (gameCharacter){
		GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Red, TEXT("ATestActor::NotifyActorBeginOverlap"));
	}
}

aaa