本篇笔记主要用于记录如何利用C++在虚幻引擎5中实现一些基本的功能需求。
目录实现功能与代码
以下代码均来自我的跳棋小游戏，所以默认Pawn的类名为ATiaoQi
构造函数中添加物体
.h
UCLASS()
class UNREALTIAOQI_API ATiaoQi : public APawn
{
GENERATED_BODY()
public:
UStaticMeshComponent* selectCircle;
ATiaoQi();
}
.cpp
ATiaoQi::ATiaoQi() {
RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootComponent"));
selectCircle = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("selectCircle"));
static ConstructorHelpers::FObjectFinder<UStaticMesh> PlaneAsset(TEXT("/Script/Engine.StaticMesh'/Engine/BasicShapes/Plane.Plane'"));
static ConstructorHelpers::FObjectFinder<UMaterial> PlaneMaterial(TEXT("/Script/Engine.Material'/Game/Material/selectBall.selectBall'")); //右键材质，复制引用即可获得该字符串
selectCircle->SetStaticMesh(PlaneAsset.Object);
selectCircle->SetMaterial(0, PlaneMaterial.Object);
const double selectCircleSize = 0.5;
selectCircle->SetWorldScale3D(FVector(selectCircleSize, selectCircleSize, selectCircleSize));
selectCircle->SetVisibility(false); //隐藏物体
}
运行时添加C++ Actor
.h
class ACBall;
UCLASS()
class UNREALTIAOQI_API ATiaoQi : public APawn
{
GENERATED_BODY()
public:
ACBall* middleBall;
}
.cpp
#include "CBall.h"
const FTransform SpawnLocAndRotation(...) //省略具体值;
middleBall = mainWorld->SpawnActorDeferred<ACBall>(ACBall::StaticClass(), SpawnLocAndRotation); //添加了ACBall类C++ Actor
运行时设置动态材质及参数
.h
class UNREALTIAOQI_API ATiaoQi : public APawn
{
GENERATED_BODY()
public:
UStaticMeshComponent* playerTriangle;
UMaterialInterface* triangleStaticMaterial;
UMaterialInstanceDynamic* DynMaterial;
}
.cpp
ATiaoQi::ATiaoQi() {
static ConstructorHelpers::FObjectFinder<UMaterial> TrianMaterial(TEXT("/Script/Engine.Material'/Game/Material/nowPlayerMaterial.nowPlayerMaterial'"));
triangleStaticMaterial = TrianMaterial.Object;
}
void ATiaoQi::initColor(const FLinearColor& TargetColor) {
DynMaterial = UMaterialInstanceDynamic::Create(triangleStaticMaterial, this);
//也可以在这声明一个局部变量作为DynMaterial
DynMaterial->SetVectorParameterValue(FName(TEXT("Color")), TargetColor); //修改动态材质参数
playerTriangle->SetMaterial(0, DynMaterial);
}
蓝图调用C++函数
在头文件中给需要调用的函数声明前添加UFUNCTION(BlueprintCallable)即可。
编译后，在蓝图中，获得需要的对象，然后Cast to对应类，再调用函数即可。
蓝图访问C++成员
在头文件中给需要访问的变量声明前添加UPROPERTY(BlueprintReadWrite)即可。
编译后，在蓝图中，获得需要的对象，然后Cast to对应类，即可读取和修改其成员。
C++调用用户控件蓝图函数
思路是这样的，用户控件蓝图继承某个C++控件类，并用蓝图重写其部分C++函数。在控件蓝图中调用指定C++类的函数，使其获得蓝图对象的指针。随后在该C++类中即可直接使用该指针调用C++控件类的函数，即调用了用户控件蓝图的函数。
为什么不直接把用户控件定为C++类而要蓝图呢？因为C++类不提供UI界面的设计器，要直接敲代码，简直没法用。
TiaoQiWidget.h：C++ UserWidget类，控件蓝图继承该类。
UCLASS()
class UNREALTIAOQI_API UTiaoQiWidget : public UUserWidget
{
GENERATED_BODY()
public:
UFUNCTION(BlueprintNativeEvent)
void humanFinish(); //这是需要调用的函数，在蓝图中重写它。
virtual void humanFinish_Implementation() {}; //必须按照这种形式声明，即在原来的函数后面添加_Implementation，不可声明其=0，但可以为空。
};
TiaoQi.h:
class UTiaoQiWidget;
UCLASS()
class UNREALTIAOQI_API ATiaoQi : public APawn
{
GENERATED_BODY()
public:
UTiaoQiWidget* widget;
UFUNCTION(BlueprintCallable)
void setWidget(UTiaoQiWidget* w=nullptr);
}
TiaoQi.cpp:
#include "TiaoQiWidget.h"
void ATiaoQi::setWidget(UTiaoQiWidget* w) { //在控件蓝图中调用，参数为self即可。
widget = w; //之后即可调用widget->humanFinish();
}
播放wav格式音效
.h
UCLASS()
class UNREALTIAOQI_API ATiaoQi : public APawn
{
GENERATED_BODY()
public:
USoundWave* jumpSoundWave[6];
ATiaoQi();
void playSound();
}
.cpp
#include "Sound/SoundWave.h"
const FString jumpSound[5] = {
TEXT("/Script/Engine.SoundWave'/Game/soundFX/Jump/s1.s1'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/Jump/s2.s2'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/Jump/s3.s3'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/Jump/s4.s4'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/Jump/s5.s5'") };
const FString nextStepSound[5] = {
TEXT("/Script/Engine.SoundWave'/Game/soundFX/humanNextStep/button01_mp3.button01_mp3'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/humanNextStep/button03_mp3.button03_mp3'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/humanNextStep/button04_mp3.button04_mp3'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/humanNextStep/button05_mp3.button05_mp3'"),
TEXT("/Script/Engine.SoundWave'/Game/soundFX/humanNextStep/button06_mp3.button06_mp3'") };
ATiaoQi::ATiaoQi() {
for (int i = 0; i < 5; ++i) {
ConstructorHelpers::FObjectFinder<USoundWave> jumpSoundObject(*jumpSound[i]);
jumpSoundWave[i] = jumpSoundObject.Object;
}
}
void ATiaoQi::playSound(){
const FVector3d T = ...; // 发声地点，省略具体值。
UGameplayStatics::PlaySoundAtLocation(this, jumpSoundWave[FMath::RandRange(0, 4)], T);
//下面这种动态载入方式也可以
USoundWave* HitSound = LoadObject<USoundWave>(this, *nextStepSound[FMath::RandRange(0,4)]);
//下面这种是直接发声，无关具体位置。
if (HitSound) {UGameplayStatics::PlaySound2D(GetWorld(), HitSound);}
}