我一直在将一些蓝图逻辑转换为C++。其中之一是一个按钮。该按钮可以在VR中按下,并具有调用委托的功能,通知任何已注册函数该按钮按下的情况。以下是AButtonItem.h类中声明委托的方式。
#pragma once
#include "BaseItem.h"
#include "ButtonItem.generated.h"
DECLARE_DYNAMIC_MULTICAST_DELEGATE(FButtonItemPressedSignatrue);
UCLASS()
class AButtonItem : public ABaseItem
{
GENERATED_BODY()
protected:
UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Touch)
float myMaxButtonPress;
public:
UPROPERTY(EditAnywhere, Category = Callback)
FButtonItemPressedSignatrue ButtonItem_OnPressed;
};
委托的广播函数会在按钮被按下时被调用,代码如下:
ButtonItem_OnPressed.Broadcast();
这个函数一定要调用,因为在调用之前我有一个打印调试信息的语句。需要注意的是,在使用蓝图逻辑时,这个函数一直可以正常工作。
以下是我尝试向委托进行注册以及声明将被调用的函数的方式:
WeaponMaker.h:
UFUNCTION()
void OnNextBladeButtonPressed();
WeaponMaker.cpp:
void AWeaponMaker::BeginPlay()
{
Super::BeginPlay();
TArray<USceneComponent*> weaponMakerComponents;
this->GetRootComponent()->GetChildrenComponents(true, weaponMakerComponents);
for (int componentIndex = 0; componentIndex < weaponMakerComponents.Num(); componentIndex++)
{
if (weaponMakerComponents[componentIndex]->GetName().Equals("NextBladeButton") == true)
{
myNextBladeButton = (AButtonItem*)weaponMakerComponents[componentIndex];
break;
}
}
if (myNextBladeButton != NULL)
{
myNextBladeButton->ButtonItem_OnPressed.AddDynamic(this, &AWeaponMaker::OnNextBladeButtonPressed);
}
}
我在函数OnNextBladeButtonPressed中设置了断点和打印语句,以便及时检查其是否起作用,但实际上从未生效。我还从头开始重新创建了蓝图,但仍然没有成功。有时编译时会因InvocationList无效而崩溃,但我也没有找到关于该问题的更多信息。最重要的是,在应该调用OnNextBladeButtonPressed时,它并未被调用。
编辑:这里是我的AButtonItem代码中调用广播函数的地方。似乎已被调用,因为我在控制台中看到了UE_LOG输出:
void AButtonItem::Tick(float deltaTime)
{
FTransform buttonWorldTransform;
FVector buttonLocalSpacePos;
FVector ownerLocalSpacePos;
FVector localDiff;
float buttonPressAmount;
if (myHasStarted == true)
{
Super::Tick(deltaTime);
if (myButtonComponent != NULL)
{
if (myPrimaryHand != NULL)
{
//Get the world space location of the button.
buttonWorldTransform = myButtonComponent->GetComponentTransform();
//Convert the location of the button and the location of the hand to local space.
buttonLocalSpacePos = buttonWorldTransform.InverseTransformPosition(myInitialOverlapPosition);
ownerLocalSpacePos = buttonWorldTransform.InverseTransformPosition(myPrimaryHand->GetControllerLocation() + (myPrimaryHand->GetControllerRotation().Vector() * myPrimaryHand->GetReachDistance()));
//Vector distance between button and hand in local space.
localDiff = ownerLocalSpacePos - buttonLocalSpacePos;
//Only interested in the z value difference.
buttonPressAmount = FMath::Clamp(FMath::Abs(localDiff.Z), 0.0f, myMaxButtonPress);
localDiff.Set(0.0f, 0.0f, buttonPressAmount);
//Set the new relative position of button based on the hand and the start button position.
myButtonComponent->SetRelativeLocation(myButtonInitialPosition - localDiff);
//UE_LOG(LogTemp, Error, TEXT("buttonPressAmount:%f"), buttonPressAmount);
if (buttonPressAmount >= myMaxButtonPress)
{
if (myHasBeenTouchedOnce == false)
{
//Fire button pressed delegate
if (ButtonItem_OnPressed.IsBound() == true)
{
ButtonItem_OnPressed.Broadcast();
AsyncTask(ENamedThreads::GameThread, [=]()
{
ButtonItem_OnPressed.Broadcast();
});
}
myHasBeenTouchedOnce = true;
myButtonComponent->SetScalarParameterValueOnMaterials("State", 1.0f);
Super::VibrateTouchingHands(EVibrationType::VE_TOUCH);
}
}
}
else
{
//Slowly reset the button position back to the initial position when not being touched.
FVector newPosition = FMath::VInterpTo(myButtonComponent->GetRelativeTransform().GetLocation(), myButtonInitialPosition, deltaTime, 10.0f);
myButtonComponent->SetRelativeLocation(newPosition);
}
}
}
}