ue4-资源加载和实例化类

加载资源，然后实例化对象

资源加载，并实例化

• 构造中加载蓝图或c++类

  • 加载并实例化一个蓝图类

        static ConstructorHelpers::FObjectFinder<UMaterial> DecalMaterialAsset(TEXT("Material'/Game/TopDownCPP/Blueprints/M_Cursor_Decal.M_Cursor_Decal'")); // 这个路径是在编辑器中右键该资源 Copy Reference，Material是 name
        if (DecalMaterialAsset.Succeeded())
        {
            CursorToWorld->SetDecalMaterial(DecalMaterialAsset.Object);
        }

  • 实例化一个c++类

        CursorToWorld = CreateDefaultSubobject<UDecalComponent>("CursorToWorld"); //必须提供一个 name（CursorToWorld）
        CursorToWorld->SetupAttachment(RootComponent); //这是一个 USceneComponent 的子类，才能显示到编辑器的 Components窗口 中，因为 USceneComponent 组件带有 transform 信息，而 UActorComponent 没有。

  • 加载一个蓝图类，并实例化成蓝图对象

        static ConstructorHelpers::FClassFinder<UCoolDownComp> CDComplAsset(TEXT("/Game/TopDownCPP/MyBp/CDCompBp")); // 这个就不能右键该资源 Copy Reference，只能是不带name的一个路径
        if (CDComplAsset.Succeeded())
        {
            UE_LOG(LogMyTest, Warning, TEXT("--- CDComplAsset.Succeeded()"));
            mCDComp = NewObject<UCoolDownComp>(this, CDComplAsset.Class, "UCoolDownComp"); //必须提供一个 name（UCoolDownComp）
            mCDComp->SetupAttachment(RootComponent);
        }

• 不在构造中实例化蓝图c++类

  • 实例化蓝图类

    1. 起个成员，可以让编辑器中指定 AMyBullet 派生的蓝图类

       UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "MyChar")
           TSubclassOf<AMyBullet> BulletClass;

    2. 实例化这个蓝图类

           FActorSpawnParameters SpawnInfo;
           SpawnInfo.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AlwaysSpawn;
           AMyBullet* mBullet = GWorld->SpawnActor<AMyBullet>(BulletClass, SpawnInfo);
           mBullet->SetPkMsg(pkMsg);

  • 实例化c++类，直接用 xxx::StaticClass()实例化

        FActorSpawnParameters SpawnInfo;
        SpawnInfo.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AlwaysSpawn;
        AMyBullet* mBullet = GWorld->SpawnActor<AMyBullet>(AMyBullet::StaticClass(), SpawnInfo);
        mBullet->SetPkMsg(pkMsg);

• 同步加载

  bool UMyBpFuncLib::TestChangeCharAnimInstance(AMyChar* _myChar, FString _pathMesh, FString _pathAnim)
  {
      FStreamableManager* stream = new FStreamableManager();
      FStringAssetReference ref1(*_pathMesh);
      USkeletalMesh* TmpMesh = Cast<USkeletalMesh>(stream->SynchronousLoad(ref1));
      _myChar->GetMesh()->SetSkeletalMesh(TmpMesh);
  
      FStringAssetReference ref2(*_pathAnim);
      UAnimBlueprint* TmpMeshAnim = Cast<UAnimBlueprint>(stream->SynchronousLoad(ref2));
      _myChar->GetMesh()->SetAnimInstanceClass((UClass*)TmpMeshAnim->GetAnimBlueprintGeneratedClass());
      delete stream;
      return true;
  }

• 异步加载参照这篇：ue4-异步加载资源