最简单的 UE 4 C++ 教程 —— 绘制 UE4 辅助调试的形状

Posted 2021-08-27 panda1234lee

 【原教程是基于 UE 4.18，我是基于 UE 4.25】

英文原地址

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