最简单的 UE 4 C++ 教程 —— 给 Actor 添加径向推力【十八】
【摘要】
原教程是基于 UE 4.18，我是基于 UE 4.25】
英文原地址
接上一节教程，本教程非常有趣，我们将通过在设定范围内的所有物体上添加径向推力来模拟爆炸。
创建一个名为 AddRadialForce 的新角色。我们不需要对头文件做任何操作。下面是由虚幻生成的默认头文件。
AddRadialForce.h
#pra...
原教程是基于 UE 4.18，我是基于 UE 4.25】
接上一节教程，本教程非常有趣，我们将通过在设定范围内的所有物体上添加径向推力来模拟爆炸。
创建一个名为 AddRadialForce 的新角色。我们不需要对头文件做任何操作。下面是由虚幻生成的默认头文件。
AddRadialForce.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 "AddRadialForce.generated.h"
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UCLASS()
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class UNREALCPP_API AAddRadialForce : 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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AAddRadialForce();
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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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};
为了在调试过程中提供帮助，让我们将 DrawDebugHelpers 头文件添加到代码中。
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#include "AddRadialForce.h"
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// add debug helpfers
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#include "DrawDebugHelpers.h"
在这个例子中，我们将在 BeginPlay() 函数中执行所有的逻辑。我们想要收集我们范围内的所有命中结果，并从范围的扫描中获得结果。为此，我们将使用 TArray 跟踪重叠的 actor。
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void AAddRadialForce::BeginPlay()
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{
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Super::BeginPlay();
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// create tarray for hit results
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TArray<FHitResult> OutHits;
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// crate tarray for sweep actors
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TArray<AActor*> SweepActors;
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}
接下来我们要声明 TArray 数组 OutHits 。我们希望扫描范围从 actor 的位置开始同时也从该位置结束，并让 CollisionShape 是一个 500 单位的球体。您可以使用 GetActorLocation() 来获取 actor 的位置，它返回一个向量。我们使用 FCollisionShape:: makephere (500.0f) 来创建一个CollisionShape。
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// Called when the game starts or when spawned
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void AAddRadialForce::BeginPlay()
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{
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Super::BeginPlay();
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// create tarray for hit results
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TArray<FHitResult> OutHits;
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// get actor locations
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FVector MyLocation = GetActorLocation();
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// start and end locations. The sphere will create the radial sweep.
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FVector Start = MyLocation;
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FVector End = MyLocation;
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// create a collision sphere
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FCollisionShape MyColSphere = FCollisionShape::MakeSphere(500.0f);
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}
为了可视化扫描的球体，我们将绘制一个调试球体。
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// Called when the game starts or when spawned
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void AAddRadialForce::BeginPlay()
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{
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Super::BeginPlay();
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// create tarray for hit results
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TArray<FHitResult> OutHits;
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// get actor locations
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FVector MyLocation = GetActorLocation();
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// start and end locations. The sphere will create the radial sweep.
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FVector Start = MyLocation;
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FVector End = MyLocation;
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// create a collision sphere
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FCollisionShape MyColSphere = FCollisionShape::MakeSphere(500.0f);
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// draw collision sphere
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DrawDebugSphere(GetWorld(), GetActorLocation(), MyColSphere.GetSphereRadius(), 50, FColor::Cyan, true);
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}
接下来我们要检查我们的 actor 在我们 BeginPlay() 时是否击中了任何东西。每个 actor 都有GetWorld 功能。从 ，我们将使用从 GetWorld() 函数得到的 SweepMultiByChannel() 函数并对其设置上面刚创建的变量作为参数。这将返回一个 bool，指示是否有其他 actor 在该 actor 的范围内。
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void AAddRadialForce::BeginPlay()
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{
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Super::BeginPlay();
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// create tarray for hit results
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TArray<FHitResult> OutHits;
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// get actor locations
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FVector MyLocation = GetActorLocation();
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// start and end locations. The sphere will create the radial sweep.
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FVector Start = MyLocation;
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FVector End = MyLocation;
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// create a collision sphere
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FCollisionShape MyColSphere = FCollisionShape::MakeSphere(500.0f);
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// draw collision sphere
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DrawDebugSphere(GetWorld(), GetActorLocation(), MyColSphere.GetSphereRadius(), 50, FColor::Cyan, true);
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// check if something got hit in the sweep
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bool isHit = GetWorld()->SweepMultiByChannel(OutHits, Start, End, FQuat::Identity, ECC_WorldStatic, MyColSphere);
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}
如果 isHit 为真，我们将通过遍历数组 OutHits ，并向每个成功 cast 的 actor 的根组件添加径向推力。
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if (isHit)
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{
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// loop through TArray
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for (auto& Hit : OutHits)
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{
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UStaticMeshComponent* MeshComp = Cast<UStaticMeshComponent>((Hit.GetActor())->GetRootComponent());
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if (MeshComp)
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{
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// alternivly you can use ERadialImpulseFalloff::RIF_Linear for the impulse to get linearly weaker as it gets further from origin.
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// set the float radius to 500 and the float strength to 2000.
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MeshComp->AddRadialImpulse(GetActorLocation(), 500.f, 2000.f, ERadialImpulseFalloff::RIF_Constant, true);
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}
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}
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}
最终完整 cpp 代码如下
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#include "AddRadialForce.h"
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// add debug helpfers
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#include "DrawDebugHelpers.h"
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// Sets default values
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AAddRadialForce::AAddRadialForce()
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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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}
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// Called when the game starts or when spawned
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void AAddRadialForce::BeginPlay()
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{
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Super::BeginPlay();
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// create tarray for hit results
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TArray<FHitResult> OutHits;
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// get actor locations
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FVector MyLocation = GetActorLocation();
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// start and end locations. The sphere will create the radial sweep.
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FVector Start = MyLocation;
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FVector End = MyLocation;
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// create a collision sphere
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FCollisionShape MyColSphere = FCollisionShape::MakeSphere(500.0f);
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// draw collision sphere
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DrawDebugSphere(GetWorld(), GetActorLocation(), MyColSphere.GetSphereRadius(), 50, FColor::Cyan, true);
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// check if something got hit in the sweep
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bool isHit = GetWorld()->SweepMultiByChannel(OutHits, Start, End, FQuat::Identity, ECC_WorldStatic, MyColSphere);
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if (isHit)
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{
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// loop through TArray
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for (auto& Hit : OutHits)
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{
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UStaticMeshComponent* MeshComp = Cast<UStaticMeshComponent>((Hit.GetActor())->GetRootComponent());
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if (MeshComp)
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{
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// alternivly you can use ERadialImpulseFalloff::RIF_Linear for the impulse to get linearly weaker as it gets further from origin.
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// set the float radius to 500 and the float strength to 2000.
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MeshComp->AddRadialImpulse(GetActorLocation(), 500.f, 2000.f, ERadialImpulseFalloff::RIF_Constant, true);
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}
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}
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}
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}
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// Called every frame
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void AAddRadialForce::Tick(float DeltaTime)
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{
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Super::Tick(DeltaTime);
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}
实际运行起来的效果图如下
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/119140900
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