[UE4]C++代码实现播放粒子特效

转自：http://aigo.iteye.com/blog/2273345

函数参数说明（在GameplayStatics.h中）

将一个粒子放到指定位置上播放： 

/** Plays the specified effect at the given location and rotation, fire and forget. The system will go away when the effect is complete. Does not replicate. 
* @param WorldContextObject - Object that we can obtain a world context from 
* @param EmitterTemplate - particle system to create 
* @param Location - location to place the effect in world space 
* @param Rotation - rotation to place the effect in world space     
* @param bAutoDestroy - Whether the component will automatically be destroyed when the particle system completes playing or whether it can be reactivated 
*/  
UFUNCTION(BlueprintCallable, Category="Effects|Components|ParticleSystem", meta=(Keywords = "particle system", WorldContext="WorldContextObject", UnsafeDuringActorConstruction = "true"))  
static UParticleSystemComponent* SpawnEmitterAtLocation(UObject* WorldContextObject, class UParticleSystem* EmitterTemplate, FVector Location, FRotator Rotation = FRotator::ZeroRotator, bool bAutoDestroy = true);  

 另一种重载形式：

static UParticleSystemComponent* SpawnEmitterAtLocation(UWorld* World, class UParticleSystem* EmitterTemplate, const FTransform& SpawnTransform, bool bAutoDestroy = true);

将一个粒子attach到某个Component上播放：

/** Plays the specified effect attached to and following the specified component. The system will go away when the effect is complete. Does not replicate. 
* @param EmitterTemplate - particle system to create 
* @param AttachComponent - Component to attach to. 
* @param AttachPointName - Optional named point within the AttachComponent to spawn the emitter at 
* @param Location - Depending on the value of Location Type this is either a relative offset from the attach component/point or an absolute world position that will be translated to a relative offset 
* @param Rotation - Depending on the value of LocationType this is either a relative offset from the attach component/point or an absolute world rotation that will be translated to a realative offset 
* @param LocationType - Specifies whether Location is a relative offset or an absolute world position 
* @param bAutoDestroy - Whether the component will automatically be destroyed when the particle system completes playing or whether it can be reactivated 
*/  
UFUNCTION(BlueprintCallable, Category="Effects|Components|ParticleSystem", meta=(Keywords = "particle system", UnsafeDuringActorConstruction = "true"))  
static UParticleSystemComponent* SpawnEmitterAttached(class UParticleSystem* EmitterTemplate, class USceneComponent* AttachToComponent, FName AttachPointName = NAME_None, FVector Location = FVector(ForceInit), FRotator Rotation = FRotator::ZeroRotator, EAttachLocation::Type LocationType = EAttachLocation::KeepRelativeOffset, bool bAutoDestroy = true);  

具体使用实例

头文件，其中MuzzleFX在蓝图中设置为具体哪个粒子资源，Mesh是要AttachTo的Component

 

UPROPERTY(EditDefaultsOnly)  
UParticleSystem* MuzzleFX;  
  
/** weapon mesh: 3rd person view */  
UPROPERTY(VisibleDefaultsOnly, Category = Mesh)  
USkeletalMeshComponent* Mesh;  

cpp中调用：

//此方法只播放一遍即结束  
UGameplayStatics::SpawnEmitterAttached(MuzzleFX, Mesh, "MyAttachPoint");  

=====================================================
上面粒子是用蓝图直接创建ParticleSystem(粒子系统)，下面是用C++代码创建ParticleSystem：

头文件中定义：

UParticleSystem* TestParticle;  
UParticleSystemComponent* LastPSC;  

创建ParticleSystem：

void AHGameMode::LoadParticlesClass()  
{  
    static ConstructorHelpers::FObjectFinder<UParticleSystem> MyParticleSystem(TEXT("ParticleSystem'/Game/Particles/Oneshot/P_mc01CIrcle05_large_oneshot.P_mc01CIrcle05_large_oneshot'"));  
    if (MyParticleSystem.Succeeded())   
    {  
        TestParticle = MyParticleSystem.Object;  
    }  
}  

播放粒子：

void AHGameMode::PlayParticle_01()  
{  
    LastPSC = UGameplayStatics::SpawnEmitterAttached(TestParticle, MyCharacter->GetMesh(), "MyParticle");  
}  

如果是循环播放的粒子，手动控制粒子的播放和关闭（如果是一个只播放一次的粒子，可以不用手动停止）：

//重复播放，只掉调用DeactivateSystem()  
LastPSC->ActivateSystem();  

参考：

How can I get a particle to spawn in a specific location?

https://answers.unrealengine.com/questions/36451/particle-spawns-in-incorrect-location.html

How can I spawn an instance of an emitter during runtime?

https://answers.unrealengine.com/questions/42209/spawning-emitter-content-that-exists-in-the-conten.html