设置椅子和桌子的质量

细节面板上的Physics---MassInKg打勾并设置质量

报错是因为没有引入 UPrimitiveComponent 所需要的头文件

#include "Components/PrimitiveComponent.h"
TotalMass += Actor->FindComponentByClass<UPrimitiveComponent>()->GetMass();

UE_LOG(LogTemp, Warning, TEXT("Total Mass is %f!"), TotalMass);// 加 * 号是取指针的数据，%f 对于小数类型，直接写小数就行，和C语言printf（）一样

为什么显示还是质量0，因为没有勾选上 Generate Overlap Events

检测方式要一致：代码：TriggerVolume->GetOverlappingActors(OUT Actors) 与 Generater Overlap Events 对应

主角没有重力，勾选上 Simulate Physics

Physics---Simulate Physics，勾选上就会有重力的效果

#include "Components/PrimitiveComponent.h"

void UOpenDoor1::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);
	//if (TriggerVolume != nullptr && TriggerVolume->IsOverlappingActor(DefaultPawn))
	if (TriggerVolume && GetTotalMassInTrigger() > 25)
	{
		OpenDoor();
		LastDoorOpenTime = GetWorld()->GetTimeSeconds();
	}
	if (GetWorld()->GetTimeSeconds() - LastDoorOpenTime > DoorOpenDuration)
	{
		CloseDoor();
	}

}


float UOpenDoor1::GetTotalMassInTrigger()
{
	TArray<AActor*> Actors;
	if (TriggerVolume == nullptr)
		return 0.0f;
	TriggerVolume->GetOverlappingActors(OUT Actors);// OUT 在语法上没有任何影响，方便阅读代码的

	float TotalMass = 0;
	for (AActor* Actor : Actors)// for(const auto& Actor : Actors)
	{
		TotalMass += Actor->FindComponentByClass<UPrimitiveComponent>()->GetMass();
	}
	UE_LOG(LogTemp, Warning, TEXT("Total Mass is %f!"), TotalMass);// 加 * 号是取指针的数据，%f 对于小数类型，直接写小数就行，和C语言printf（）一样
	return TotalMass;
}