最简单的 UE 4 C++ 教程 —— 触发区域内的键盘响应开关灯【二十五】
原教程是基于 UE 4.18，我是基于 UE 4.25】
接上一节教程，创建一个新的 C++ Actor 子类并将其命名为 LightSwitchPushButton 。我们将在头文件中定义四个东西 —— 我们将定义一个 UPointLightComponent、USphereComponent、float 变量和 void 函数。
下面是最终的头代码。
LightSwitchPushButton.h
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#pragma once
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#include "CoreMinimal.h"
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#include "GameFramework/Actor.h"
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#include "LightSwitchPushButton.generated.h"
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UCLASS()
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class UNREALCPP_API ALightSwitchPushButton : public AActor
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{
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GENERATED_BODY()
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public:
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// Sets default values for this actor's properties
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ALightSwitchPushButton();
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protected:
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// Called when the game starts or when spawned
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virtual void BeginPlay() override;
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public:
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// Called every frame
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// virtual void Tick(float DeltaTime) override;
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// declare point light comp
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UPROPERTY(VisibleAnywhere, Category = "Light Switch")
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class UPointLightComponent* PointLight;
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// declare sphere comp
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UPROPERTY(VisibleAnywhere, Category = "Light Switch")
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class USphereComponent* LightSphere;
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// declare light intensity variable
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UPROPERTY(VisibleAnywhere, Category = "Light Switch")
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float LightIntensity;
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// declare ToggleLight function
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UFUNCTION(BlueprintCallable, Category = "Light Switch")
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void ToggleLight();
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};
接下来，在我们的 .cpp 文件中，让我们首先 #include 我们将在代码中使用的必要脚本。包括Components / PointLightComponent.h 和 Components/ spherecomcomponent .h 两个文件。
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#include "LightSwitchPushButton.h"
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// include these header files
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#include "Components/PointLightComponent.h"
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#include "Components/SphereComponent.h"
我们将在构造函数中设置 actor 的所有默认属性。首先让我们设置我们的 float 变量 LightIntensity 为 3000.0f，它将使光相对于其他对象看起来足够明亮。接下来，我们将创建我们的UPointLightComponent 并将它设置为我们的 RootComponent 。之后，我们将创建USphereComponent，当我们的玩家在半径内时，它将作为碰撞球体。然后，我们将创建简单的ToggleLight() 函数来切换灯光的可见性状态。稍后我们将从玩家代码中调用该函数。下面是LightSwitchPushButton 角色的最后一个 .cpp 文件。
LightSwitchPushButton.cpp
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#include "LightSwitchPushButton.h"
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#include "Components/PointLightComponent.h"
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#include "Components/SphereComponent.h"
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// Sets default values
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ALightSwitchPushButton::ALightSwitchPushButton()
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{
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// Set this actor to call Tick() every frame. You can turn this off to improve performance if you don't need it.
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PrimaryActorTick.bCanEverTick = true;
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LightIntensity = 3000.0f;
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PointLight = CreateDefaultSubobject<UPointLightComponent>(TEXT("Point Light"));
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PointLight->Intensity = LightIntensity;
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//PointLight->bVisible = true; ///< 过时了
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//PointLight->SetVisibleFlag(true);
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PointLight->SetVisibility(true);
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RootComponent = PointLight;
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LightSphere = CreateDefaultSubobject<USphereComponent>(TEXT("Light Sphere Component"));
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LightSphere->InitSphereRadius(300.0f);
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LightSphere->SetCollisionProfileName(TEXT("Trigger"));
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LightSphere->SetCollisionResponseToChannel(ECC_Pawn, ECR_Ignore);
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LightSphere->SetupAttachment(RootComponent);
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}
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// Called when the game starts or when spawned
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void ALightSwitchPushButton::BeginPlay()
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{
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Super::BeginPlay();
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}
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void ALightSwitchPushButton::ToggleLight()
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{
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PointLight->ToggleVisibility();
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}
接下来，和上一节类似，让我们向项目添加一个 Action 输入。在本例中，我们将把 Action 输入绑定到键盘的 F键。转到 编辑>项目设置 ( Edit > Project Settings)。然后选择 Input 选项。单击 Action Mappings 旁边的加号。调用新的输入 Action 并从下拉菜单中选择 F 。
【以下我们把目光转到 xxxCharacter.h / .cpp 上】
在 xxxCharacter.h文件中，在 OnFire 方法下添加 OnAction 方法。
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protected:
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/** Fires a projectile. */
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void OnFire();
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// on action
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void OnAction();
此外，我们还必须包含 LightSwitchPushButton 头文件，这样我们的角色才能访问它的功能。
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#include "CoreMinimal.h"
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#include "GameFramework/Character.h"
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// include our new LightSwitchPushButton header file
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#include "LightSwitchPushButton/LightSwitchPushButton.h"
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#include "UnrealCPPCharacter.generated.h"
然后为玩家当前重叠的灯开关声明一个变量 CurrentLightSwitch 。此外，我们还需要声明重叠事件，来使得当玩家处于光的球体组件的半径内时，触发我们想要运行的函数。
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// declare overlap begin function
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UFUNCTION()
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void OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);
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// declare overlap end function
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UFUNCTION()
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void OnOverlapEnd(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);
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// declare current light switch
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class ALightSwitchPushButton* CurrentLightSwitch;
同时还声明了 UCapsuleComponent 来处理我们的触发事件
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UPROPERTY(VisibleAnywhere, Category = "Trigger Capsule")
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class UCapsuleComponent* TriggerCapsule;
在构造函数中添加触发器胶囊并将其绑定到重叠事件。接着设置变量 CurrentLightSwitch 为NULL。
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AUnrealCPPCharacter::AUnrealCPPCharacter()
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{
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...
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// create trigger capsule
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TriggerCapsule = CreateDefaultSubobject<UCapsuleComponent>(TEXT("Trigger Capsule"));
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TriggerCapsule->InitCapsuleSize(55.f, 96.0f);;
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TriggerCapsule->SetCollisionProfileName(TEXT("Trigger"));
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TriggerCapsule->SetupAttachment(RootComponent);
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// bind trigger events
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TriggerCapsule->OnComponentBeginOverlap.AddDynamic(this, &AUnrealCPPCharacter::OnOverlapBegin);
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TriggerCapsule->OnComponentEndOverlap.AddDynamic(this, &AUnrealCPPCharacter::OnOverlapEnd);
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// set current light switch to null
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CurrentLightSwitch = NULL;
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}
进一步，将 Action 输入绑定连接到玩家
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void AUnrealCPPCharacter::SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent)
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{
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...
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// Bind action event
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PlayerInputComponent->BindAction("Action", IE_Pressed, this, &AUnrealCPPCharacter::OnAction);
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}
将 OnAction() 函数添加到玩家脚本中。该函数将检查 CurrentLightSwitch 是否为 NULL 。如果CurrentLightSwitch 不为 NULL，那么当玩家按下动作键 F 时，将切换灯光的可见性（开关灯）。然后，添加重叠函数来设置和取消 CurrentLightSwitch
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void AUnrealCPPCharacter::OnAction()
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{
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if(CurrentLightSwitch)
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{
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CurrentLightSwitch->ToggleLight();
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}
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}
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// overlap on begin function
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void AUnrealCPPCharacter::OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
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{
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if (OtherActor && (OtherActor != this) && OtherComp && OtherActor->GetClass()->IsChildOf(ALightSwitchPushButton::StaticClass()))
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{
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CurrentLightSwitch = Cast<ALightSwitchPushButton>(OtherActor);
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}
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}
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// overlap on end function
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void AUnrealCPPCharacter::OnOverlapEnd(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex)
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{
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if (OtherActor && (OtherActor != this) && OtherComp)
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{
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CurrentLightSwitch = NULL;
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}
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}
编译代码。拖放 actor （LightSwitchPushButton）到场景中，当玩家进入球形触发区域，点击 F 键开关灯。
最后的效果图如下
文章来源: panda1234lee.blog.csdn.net，作者：panda1234lee，版权归原作者所有，如需转载，请联系作者。
原文链接：panda1234lee.blog.csdn.net/article/details/119204101
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