虛幻4 C++實現物體的上下浮動

虛幻4 C++實現物體的上下浮動

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1. 新建一個C++類，命名爲FloatingActor
2. 在FloatingActor.h中聲明變量floatK和floatSpeed，具體用途看註釋：

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "Components/StaticMeshComponent.h"
#include "FloatingActor.generated.h"

UCLASS()
class TPCPP_API AFloatingActor : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AFloatingActor();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

private:
    //物體運動的時間
	float runninfTime;

	UStaticMeshComponent* staticMesh;

public:
	UPROPERTY(EditAnywhere, Category = "Float|value")
		//物體上下移動的振幅
		float floatK = 20.f;

	UPROPERTY(EditAnywhere, Category = "Float|value")
		//物體上下浮動的速率
		float floatSpeed = 1.f;
};

  3. 在FloatingActor.CPP中的Tick中寫入相關代碼是物體發生位移：

// Fill out your copyright notice in the Description page of Project Settings.


#include "FloatingActor.h"
#include "Engine/StaticMesh.h"

// Sets default values
AFloatingActor::AFloatingActor()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

	staticMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("StaticMesh"));

	UStaticMesh* actorMesh = LoadObject<UStaticMesh>(NULL, TEXT("StaticMesh'/Game/StarterContent/Shapes/Shape_Cone.Shape_Cone'"));

	staticMesh->SetStaticMesh(actorMesh);
}

// Called when the game starts or when spawned
void AFloatingActor::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AFloatingActor::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

	//獲取物體當前的位置並賦值給newLocation
	FVector newLocation = GetActorLocation();
	//計算這一幀因該上升的高度
	float deltaHeight = FMath::Sin(runninfTime + DeltaTime * floatSpeed) - FMath::Sin(runninfTime);
	//物體的高度加上這一幀因該上升的高度
	newLocation.Z += deltaHeight * floatK;
	//累計時間加上幀時間
	runninfTime += DeltaTime * floatSpeed;
	//設置物體的位置爲新的位置
	SetActorLocation(newLocation);
}