UE4 碰撞射线检测

/**
默认 TraceTypeQuery1 —— Visibility
默认 TraceTypeQuery2 —— Camera
*/
void ATraceCharacter::traceByChannel() {
	//获取该组件的拥有者
	AActor* MyOwner = GetOwner();
	//射线的开始位置和结束位置
	FVector Start;
	FRotator StartRotation;
	MyOwner->GetActorEyesViewPoint(Start, StartRotation);

	//Start = Mesh1P->GetComponentLocation();

	FVector End = Start + StartRotation.Vector() * 1000.0f;
	FHitResult Hit;
	//根据通道查询 在这里需要注意AddIgnoredActor添加了该射线忽略的Actor，不然会造成检测错误
	FCollisionQueryParams QueryParams;
	QueryParams.AddIgnoredActor(MyOwner);

	/** 
	* 参数类型
	*Hit碰撞信息 起始点、结束点、碰撞通道、查询参数
	*/
	bool BIsTraced = GetWorld()->LineTraceSingleByChannel(Hit, Start, End, ECollisionChannel::ECC_Visibility, QueryParams);
	if (BIsTraced) {
		UKismetSystemLibrary::PrintString(GetWorld(), FString::Printf(TEXT("LineTraceSingleByChannel : %s"), *Hit.Actor->GetName()));
	}
}

/**
默认 ObjectTypeQuery1 —— WorldStatic
默认 ObjectTypeQuery2 —— WorldDynamic
默认 ObjectTypeQuery3 —— Oawn
默认 ObjectTypeQuery4 —— PhysicasBody
默认 ObjectTypeQuery5 —— Vehicle
默认 ObjectTypeQuery6 —— Destructible
*/
void ATraceCharacter::traceByObjType() {
	//获取该组件的拥有者
	AActor* MyOwner = GetOwner();
	//射线的开始位置和结束位置
	FVector Start;
	FRotator StartRotation;
	MyOwner->GetActorEyesViewPoint(Start, StartRotation);
	FVector End = Start + StartRotation.Vector() * 4000;
	//碰撞对象查询
	FCollisionObjectQueryParams ObjectQueryParams;
	ObjectQueryParams.AddObjectTypesToQuery(ECollisionChannel::ECC_WorldStatic);
	//单通道射线根据对象类型检测
	FHitResult Hit;

	/**
	* 参数类型
	* Hit碰撞信息、起始点、结束点、对象检测参数。
	*/
	bool BIsTraced = GetWorld()->LineTraceSingleByObjectType(Hit, Start, End, ObjectQueryParams);
	if (BIsTraced) {
		UKismetSystemLibrary::PrintString(GetWorld(), FString::Printf(TEXT("LineTraceSingleByObjectType : %s"), *Hit.Actor->GetName()));
	}
}

以下是不常用

void ATraceCharacter::traceHit() {

	AMainPlayerController* PC = Cast<AMainPlayerController>(UGameplayStatics::GetPlayerController(GetWorld(), 0));

	//获取屏幕宽高
	int32 width = 0;
	int32 height = 0;
	PC->GetViewportSize(width, height);

	//将屏幕位置投影到世界
	FVector STMPos;
	FVector STMDir;
	//宽高/2就是屏幕中心点
	PC->DeprojectScreenPositionToWorld(width / 2, height / 2, STMPos, STMDir);

	FVector CameraPos = PC->PlayerCameraManager->GetCameraLocation();
	FVector CameraDir = PC->PlayerCameraManager->GetActorForwardVector() * 300;
	FHitResult Hit;
	//摄像机发射射线，单射线检查，只有一个目标
	//Start:CameraPos + CameraDir
	//End: CameraPos + STMDir * 5000 ,相机位置往世界方向发射一条5000长的射线
	if (GetWorld()->LineTraceSingleByChannel(Hit, CameraPos + CameraDir, CameraPos + STMDir * 5000, ECC_Camera)) {
		FString msg = Hit.GetActor()->GetName();
		GEngine->AddOnScreenDebugMessage(-1, 2.0, FColor::Red, msg + TEXT(" hitting..."));

		UTraceInterface* trace = Cast<UTraceInterface>(Hit.Actor);
		if (trace) {
			UE_LOG(LogTemp, Warning, TEXT("**************"));
		}

	}
}

void ATraceCharacter::traceFire() {
	AMainPlayerController* PC = Cast<AMainPlayerController>(UGameplayStatics::GetPlayerController(GetWorld(), 0));

	FVector FireStart, FireEnd;
	FireStart = FirstPersonCameraComponent->GetComponentLocation() + FirstPersonCameraComponent->GetForwardVector();
	FireEnd = FirstPersonCameraComponent->GetForwardVector() * 1500 + FireStart;
	FHitResult OutHit;
	TArray<AActor*> ActorsToIgnotre;
	UKismetSystemLibrary::LineTraceSingle(this, FireStart, FireEnd, ETraceTypeQuery::TraceTypeQuery1, false, ActorsToIgnotre, EDrawDebugTrace::ForDuration, OutHit, true);

	UTraceInterface* trace = Cast<UTraceInterface>(OutHit.Actor);
	if (trace) {
		FString msg = OutHit.GetActor()->GetName();
		GEngine->AddOnScreenDebugMessage(-1, 2.0, FColor::Red, msg + TEXT(" hitting..."));
	}
}

void ATraceCharacter::traceFire2() {
	FRotator cameraRotator = FirstPersonCameraComponent->GetComponentRotation();
	//相机向前的方向
	FVector cameraForward = UKismetMathLibrary::GetForwardVector(cameraRotator);
	UE_LOG(LogTemp, Warning, TEXT("cameraForward: (X:%f,Y:%f,Z:%f)"), cameraForward.X, cameraForward.Y, cameraForward.Z);
	//相机的位置 向量的取值范围在 -1 ~ 1之间
	FVector cameraLocation = FirstPersonCameraComponent->GetComponentLocation();
	UE_LOG(LogTemp, Warning, TEXT("cameraLocation: (X:%f,Y:%f,Z:%f)"), cameraLocation.X, cameraLocation.Y, cameraLocation.Z);

	//射线结束位置
	FVector endLocation = cameraLocation + cameraForward * 1500;
	UE_LOG(LogTemp, Warning, TEXT("endLocation: (X:%f,Y:%f,Z:%f)"), endLocation.X, endLocation.Y, endLocation.Z);

	FHitResult hitResult;
	TArray<AActor*>ignoreArray;
	bool bHit = UKismetSystemLibrary::LineTraceSingle(GetWorld(), cameraLocation, endLocation
		, ETraceTypeQuery::TraceTypeQuery1, false, ignoreArray, EDrawDebugTrace::Persistent
		, hitResult, true/*, FLinearColor::Red, FLinearColor::Green, 2.0*/);
	if (bHit){
		UKismetSystemLibrary::PrintString(GetWorld(),FString::Printf(TEXT("Name:%s"), *hitResult.Actor->GetName()));
	}
}

void ATraceCharacter::traceByChannelDraw() {
	// 碰撞参数
	FCollisionQueryParams CollisonQueryParams(TEXT("QueryParams"), true, NULL);
	CollisonQueryParams.bTraceComplex = true;
	CollisonQueryParams.bReturnPhysicalMaterial = false;
	CollisonQueryParams.AddIgnoredActor(this);
	// 起始点和检测结果
	FVector BeginLoc = GetActorLocation();
	FVector EndLoc = BeginLoc + GetActorForwardVector() * 4000;
	FHitResult HitResult;
	// 射线检测
	GetWorld()->LineTraceSingleByChannel(HitResult, BeginLoc, EndLoc, ECollisionChannel::ECC_Visibility, CollisonQueryParams);
	// 绘制射线
	//DrawDebugLine(GetWorld(), BeginLoc, HitResult.GetActor() ? HitResult.Location : EndLoc, FColor::Red, false, 1.0f);
	if (HitResult.GetActor()) {
		UKismetSystemLibrary::PrintString(GetWorld(), HitResult.GetActor()->GetName());
	}
}

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