最简单的 UE 4 C++ 教程 —— 绘制 UE4 辅助调试的形状【六】

喜欢ヅ旅行 2022-08-31 14:23 5阅读 0赞

**【原教程是基于 UE 4.18，我是基于 UE 4.25】**

[英文原地址][Link 1]

接上一节，在本教程中，我们将绘制 **DrawDebugHelpers.h** 提供的多个调试形状。**[DrawDebugHelpers.h][]** 包含的相关的所有内容都是由 UE4 提供的。

创建一个新的 C++ Actor 子类并将其命名为 **MyDrawDebugHelpers** 。在头文件中，我们将在 .h 中声明将在 .cpp 文件中使用的变量，它们也可以在编辑器中进行编辑。我们将创建一个**FVectors**，一个 **FMatrix**，一个 **FBox**，和一个 **FTransform**。

该头文件代码如下：

#pragma once
    
    #include "CoreMinimal.h"
    #include "GameFramework/Actor.h"
    #include "MyDrawDebugHelpers.generated.h"
    
    UCLASS()
    class UNREALCPP_API AMyDrawDebugHelpers : public AActor
    {
    	GENERATED_BODY()
    	
    public:	
    	// Sets default values for this actor's properties
    	AMyDrawDebugHelpers();
    
    protected:
    	// Called when the game starts or when spawned
    	virtual void BeginPlay() override;
    
    public:	
    	// Called every frame
    	virtual void Tick(float DeltaTime) override;
    
    	// declare location variables
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FVector LocationOne;
    
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FVector LocationTwo;
    
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FVector LocationThree;
    
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FVector LocationFour;
    
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FVector LocationFive;
    
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FMatrix CircleMatrix;
    
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FBox MyBox;
    
    	UPROPERTY(EditAnywhere, Category = "Locations")
    	FTransform MyTransform;
    	
    };

同时别忘了还要 include 头文件 **DrawDebugHelpers.h**

#include "MyDrawDebugHelpers.h"
    // include draw debu helpers header file
    #include "DrawDebugHelpers.h"

在.cpp文件中，我们将首先为变量指定默认值。下面是我们将为默认值添加的初始化代码。

// Sets default values
    AMyDrawDebugHelpers::AMyDrawDebugHelpers()
    {
     	// 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;
    
    	// init variables with values
    	LocationOne = FVector(0,0,600);
    	LocationTwo = FVector(0,-600,600);
    	LocationThree = FVector(0,600,600);
    	LocationFour = FVector(-300,0,600);
    	LocationFive = FVector(-400,-600,600);
    	
    	MyBox = FBox(FVector(0,0,0), FVector(200,200,200));
    }

接下来，我们将在 BeginPlay() 函数中绘制许多不同的形状。

下面是我们将添加到 BeginPlay() 来绘制所有形状的函数。

// Called when the game starts or when spawned
    void AMyDrawDebugHelpers::BeginPlay()
    {
    	Super::BeginPlay();
    
    	DrawDebugPoint(GetWorld(), LocationOne, 200, FColor(52,220,239), true);
    
    	DrawDebugSphere(GetWorld(), LocationTwo, 200, 26, FColor(181,0,0), true, -1, 0, 2);
    
    	DrawDebugCircle(GetWorld(), CircleMatrix, 200, 50, FColor(0,104,167), true, -1, 0, 10);
    
    	DrawDebugCircle(GetWorld(), LocationFour, 200, 50, FColor(0,0,0), true, -1, 0, 10);
    
    	DrawDebugSolidBox(GetWorld(), MyBox, FColor(20, 100, 240), MyTransform, true);
    
    	DrawDebugBox(GetWorld(), LocationFive, FVector(100,100,100), FColor::Purple, true, -1, 0, 10);
    
    	DrawDebugLine(GetWorld(), LocationTwo, LocationThree, FColor::Emerald, true, -1, 0, 10);
    
    	DrawDebugDirectionalArrow(GetWorld(), FVector(-300, 600, 600), FVector(-300, -600, 600), 120.f, FColor::Magenta, true, -1.f, 0, 5.f);
    	
    	DrawDebugCrosshairs(GetWorld(), FVector(0,0,1000), FRotator(0,0,0), 500.f, FColor::White, true, -1.f, 0);
    	
    }

编译代码。将你的新 Actor 实例对象拖放到场景中，则形状将在游戏中绘制。同时还可以在 Actor 的详细信息面板中编辑那些变量。

下面是最终的 .cpp 代码。

#include "MyDrawDebugHelpers.h"
    // include draw debu helpers header file
    #include "DrawDebugHelpers.h"
    
    
    // Sets default values
    AMyDrawDebugHelpers::AMyDrawDebugHelpers()
    {
     	// 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;
    
    	// init variables with values
    	LocationOne = FVector(0,0,600);
    	LocationTwo = FVector(0,-600,600);
    	LocationThree = FVector(0,600,600);
    	LocationFour = FVector(-300,0,600);
    	LocationFive = FVector(-400,-600,600);
    	
    	MyBox = FBox(FVector(0,0,0), FVector(200,200,200));
    }
    
    // Called when the game starts or when spawned
    void AMyDrawDebugHelpers::BeginPlay()
    {
    	Super::BeginPlay();
    
    	DrawDebugPoint(GetWorld(), LocationOne, 200, FColor(52,220,239), true);
    
    	DrawDebugSphere(GetWorld(), LocationTwo, 200, 26, FColor(181,0,0), true, -1, 0, 2);
    
    	DrawDebugCircle(GetWorld(), CircleMatrix, 200, 50, FColor(0,104,167), true, -1, 0, 10);
    
    	DrawDebugCircle(GetWorld(), LocationFour, 200, 50, FColor(0,0,0), true, -1, 0, 10);
    
    	DrawDebugSolidBox(GetWorld(), MyBox, FColor(20, 100, 240), MyTransform, true);
    
    	DrawDebugBox(GetWorld(), LocationFive, FVector(100,100,100), FColor::Purple, true, -1, 0, 10);
    
    	DrawDebugLine(GetWorld(), LocationTwo, LocationThree, FColor::Emerald, true, -1, 0, 10);
    
    	DrawDebugDirectionalArrow(GetWorld(), FVector(-300, 600, 600), FVector(-300, -600, 600), 120.f, FColor::Magenta, true, -1.f, 0, 5.f);
    	
    	DrawDebugCrosshairs(GetWorld(), FVector(0,0,1000), FRotator(0,0,0), 500.f, FColor::White, true, -1.f, 0);
    	
    }
    
    // Called every frame
    void AMyDrawDebugHelpers::Tick(float DeltaTime)
    {
    	Super::Tick(DeltaTime);
    
    }

最终效果如下

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BhbmRhMTIzNGxlZQ_size_16_color_FFFFFF_t_70][]

[Link 1]: https://unrealcpp.com/draw-debug-helpers/
[DrawDebugHelpers.h]: https://github.com/EpicGames/UnrealEngine/blob/release/Engine/Source/Runtime/Engine/Public/DrawDebugHelpers.h
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BhbmRhMTIzNGxlZQ_size_16_color_FFFFFF_t_70]: /images/20220829/828decda8f374017b92515ae90e8652f.png