UE5 C++ 3D血条响应人物受伤案例

一.3Dwidget

1.创建C++ Userwidget的 MyHealthWidget，声明当前血量和最大血量

UCLASS()
class PRACTICEC_API UMyHealthWidget : public UUserWidget
{
	GENERATED_BODY()
public:
	UPROPERTY(EditAnywhere,BlueprintReadWrite,Category  = "MyWidget")
	float CurrentHealth = 100.0f;
	UPROPERTY(EditAnywhere,BlueprintReadWrite,Category = "MyWidget")
	float MaxHealth = 100.0f; //可以给默认值

};

2.创建UMG的蓝图，ClassSetting里继承 MyHealthWidget.

二.渲染到屏幕

在Charactor的构造函数中，构建子组件。并且静态加载UMG类。设置位置，屏幕，大小等。

	UWidgetComponent* MyWidgetHealth;

	MyWidgetHealth = CreateDefaultSubobject<UWidgetComponent>(TEXT("MyWidgetComponent"));
	MyWidgetHealth->SetupAttachment(RootComponent);
	static ConstructorHelpers::FClassFinder<UUserWidget>WidgetClass(TEXT("/Script/UMGEditor.WidgetBlueprint'/Game/UMG_Health.UMG_Health_C'"));    //静态加载
	MyWidgetHealth->SetWidgetClass(WidgetClass.Class);
	MyWidgetHealth->SetRelativeLocation(FVector(0,0,100)); 
	MyWidgetHealth->SetWidgetSpace(EWidgetSpace::Screen);  //  输出到屏幕
	MyWidgetHealth->SetDrawSize(FVector2D(400,20));

三.碰撞伤害

1.在Actor 添加头文件和碰撞函数

#include "Kismet/GameplayStatics.h"  //Aplaydamage 函数库里的头文件
#include "MyCharacter.h"  //后面用于转化

	UFUNCTION()
	void BeginOverlapFunction(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);
	UFUNCTION()
	void EndOverlapFunction( UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex); //四个参数
	// FComponentEndOverlapSignature, UPrimitiveComponent, OnComponentEndOverlap, UPrimitiveComponent*, OverlappedComponent, AActor*, OtherActor, UPrimitiveComponent*, OtherComp, int32, OtherBodyIndex

2.在CPP里实现，如果人物刚碰撞 ApplyDamage();

void AMyActor::BeginOverlapFunction(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
	AMyCharacter* MyCharacter = Cast<AMyCharacter>(OtherActor); //转换
	if (MyCharacter)
	{
		UGameplayStatics::ApplyDamage(MyCharacter,5.0f,nullptr,this,UDamageType::StaticClass());  //应用伤害
	}
	GEngine->AddOnScreenDebugMessage(-1,5.0f,FColor::Red,TEXT("BeginOverLapEvent is Success"));
	MyParticle->Activate(); //激活
}

四.人物收到伤害血条响应

重写内部受伤函数

	virtual float TakeDamage(float DamageAmount,FDamageEvent const &DamageEvent,class AController*EventInstigator,AActor* DamagerCausser)override; //重写系统内部的TakeDamage

float AMyCharacter::TakeDamage(float DamageAmount, FDamageEvent const& DamageEvent, AController* EventInstigator, AActor* DamagerCausser)
{
	UMyHealthWidget* MyWidget = Cast<UMyHealthWidget>(MyWidgetHealth->GetUserWidgetObject());
	if (MyWidget)
	{
		if (MyWidget->CurrentHealth > 0)
		{
			MyWidget->CurrentHealth -= 5.f;
		}
		else
		{
			return 0.f;
		}
	}
	return 0.0f;
}

获得指针UserWidget 转换为 UMyHealthWidget，做相应的逻辑操作。