C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

我们已经上线了 Agora Unreal SDK，提供了支持 Blueprint 和 C++ 的两个版本 SDK。我们分享了如何基于 Blueprint 在游戏中创建实时音视频功能。在本文中，我们来分享如何基于声网 Agora Unreal SDK C++版本，在游戏中实现实时音视频功能。

本篇教程较长，建议在 Web 浏览器端浏览，体验更好。

准备工作

需要的开发环境和需要准备的与 Blueprint 一样：

Unreal 4.34 以上版本
Visual Studio 或 Xcode（版本根据 Unreal 配置要求而定）
运行 Windows 7 以上系统的 PC 或一台 Mac
Agora 注册账号一枚（免费注册，见官网 Agora.io）
如果你的企业网络存在防火墙，请在声网文档中心搜索「应用企业防火墙限制」，进行配置。

新建项目

如果你已经有 Unreal 项目了，可以跳过这一步。在 Unreal 中创建一个 C++类型的项目。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

确保在 [your_project]/Source/[project_name]/[project_name].Build.cs文件的 PrivateDependencyModuleNames一行，去掉注释。Unreal 默认是将它注释掉的，这会导致在编译的时候报错。

// Uncomment if you are using Slate UI
PrivateDependencyModuleNames.AddRange(new string[] { "UMG", "Slate", "SlateCore" });

接下来我们在项目中集成 Agora SDK

1.将 SDK 复制到这个路径下 [your_project]/Plugins

2.把插件依赖添加到[your_project]/Source/[project_name]/[project_name].Build.cs文件的私有依赖（Private Dependencies）部分 PrivateDependencyModuleNames.AddRange(new string[] { "AgoraPlugin", "AgoraBlueprintable" });

3.重启 Unreal

4.点击 Edit->Plugin，在分类中找到 Project->Other，确定插件已经生效

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

创建新的 Level

接下来我们将创建一个新的 Level，在那里建立我们的游戏环境。有几种不同的方法可以创建一个新的 Level，我们将使用文件菜单的方法，其中列出了关卡选择选项。

在虚幻编辑器里面，点击文件菜单选项，然后选择新建 Level......

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

然后会打开一个新的对话框。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

选择Empty Level ，然后指定一个存储的路径。

创建核心类

在这里我们要创建两个类：VideoFrameObserver 和VideoCall C++ Class。他们会负责与 Agora SDK 进行通信。

首先是 VideoFrameObserver。VideoFrameObserver 执行的是 agora::media::IVideoFrameObserver。这个方法在 VideoFrameObserver 类中负责管理视频帧的回调。它是用 registerVideoFrameObserver 在 agora::media::IMediaEngine 中注册的。

在 Unreal 编辑器中，选择 File->Add New C++ Class。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

父类谁定为 None，然后点击下一步。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

为 VideoFrameObserver明明，然后选择 Create Class。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

创建 VideoFrameObserver 类接口。

打开 VideoFrameObserver.h 文件然后添加如下代码：

//VideoFrameObserver.h
#include "CoreMinimal.h"
#include <functional>
#include "AgoraMediaEngine.h"
class AGORAVIDEOCALL_API VideoFrameObserver : public agora::media::IVideoFrameObserver
{
public:
virtual ~VideoFrameObserver() = default;
public:
bool onCaptureVideoFrame(VideoFrame& videoFrame) override;
bool onRenderVideoFrame(unsigned int uid, VideoFrame& videoFrame) override;
void setOnCaptureVideoFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> callback);
void setOnRenderVideoFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> callback);
virtual VIDEO_FRAME_TYPE getVideoFormatPreference() override { return FRAME_TYPE_RGBA; }
private:
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnCaptureVideoFrame;
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnRenderVideoFrame;
};

AGORAVIDEOCALL_API 是项目依赖的定义，而不是由Unreal 生成的你自己的定义。

重写onCaptureVideoFrame/onRenderVideoFrame方法

onCaptureVideoFrame 会获取到摄像头捕获的画面，转换为 ARGB 格式并触发 OnCaptureVideoFrame 回调。

onRenderVideoFrame 讲收到的特定用户画面转换为 ARGB 格式，然后触发 onRenderVideoFrame 回调。

//VideoFrameObserver.cpp
bool VideoFrameObserver::onCaptureVideoFrame(VideoFrame& Frame)
{
const auto BufferSize = Frame.yStride*Frame.height;
if (OnCaptureVideoFrame)
{
OnCaptureVideoFrame( static_cast< uint8_t* >( Frame.yBuffer ), Frame.width, Frame.height, BufferSize );
}
return true;
}
bool VideoFrameObserver::onRenderVideoFrame(unsigned int uid, VideoFrame& Frame)
{
const auto BufferSize = Frame.yStride*Frame.height;
if (OnRenderVideoFrame)
{
OnRenderVideoFrame( static_cast<uint8_t*>(Frame.yBuffer), Frame.width, Frame.height, BufferSize );
}
return true;
}

增加setOnCaptureVideoFrameCallback/setOnRenderVideoFrameCallback方法。

设定回调，用来获取摄像头获取到的本地画面和远端的画面。

//VideoFrameObserver.cpp
void VideoFrameObserver::setOnCaptureVideoFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> Callback)
{
OnCaptureVideoFrame = Callback;
}
void VideoFrameObserver::setOnRenderVideoFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> Callback)
{
OnRenderVideoFrame = Callback;
}

创建视频通话C++类

VideoCall 类管理与 Agora SDK 的通信。需要创建多个方法和接口。

创建类接口

回到 Unreal 编辑器，再创建一个新的 C++类，命名为 VideoCall.h。然后进入VideoCall.h文件，添加一下接口：

//VideoCall.h
#pragma once
#include "CoreMinimal.h"
#include <functional>
#include <vector>
#include "AgoraRtcEngine.h"
#include "AgoraMediaEngine.h"
class VideoFrameObserver;
class AGORAVIDEOCALL_API VideoCall
{
public:
VideoCall();
~VideoCall();
FString GetVersion() const;
void RegisterOnLocalFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnLocalFrameCallback);
void RegisterOnRemoteFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnRemoteFrameCallback);
void StartCall(
const FString& ChannelName,
const FString& EncryptionKey,
const FString& EncryptionType);
void StopCall();
bool MuteLocalAudio(bool bMuted = true);
bool IsLocalAudioMuted();
bool MuteLocalVideo(bool bMuted = true);
bool IsLocalVideoMuted();
bool EnableVideo(bool bEnable = true);
private:
void InitAgora();
private:
TSharedPtr<agora::rtc::ue4::AgoraRtcEngine> RtcEnginePtr;
TSharedPtr<agora::media::ue4::AgoraMediaEngine> MediaEnginePtr;
TUniquePtr<VideoFrameObserver> VideoFrameObserverPtr;
//callback
//data, w, h, size
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnLocalFrameCallback;
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnRemoteFrameCallback;
bool bLocalAudioMuted = false;
bool bLocalVideoMuted = false;
};

创建初始化方法

进入 VideoCall.cpp 文件，添加以下代码：

//VideoCall.cpp
#include "AgoraVideoDeviceManager.h"
#include "AgoraAudioDeviceManager.h"
#include "MediaShaders.h"
#include "VideoFrameObserver.h"

用agora::rtc::ue4::AgoraRtcEngine::createAgoraRtcEngine()创建引擎，初始化 RtcEnginePtr 变量。创建一个RtcEngineContext对象，然后在ctx.eventHandler 和ctx.appId中设定 event handler 和 App ID 。初始化引擎，并创建AgoraMediaEngine对象，初始化 MediaEnginePtr。

//VideoCall.cpp
VideoCall::VideoCall()
{
InitAgora();
}
VideoCall::~VideoCall()
{
StopCall();
}
void VideoCall::InitAgora()
{
RtcEnginePtr = TSharedPtr<agora::rtc::ue4::AgoraRtcEngine>(agora::rtc::ue4::AgoraRtcEngine::createAgoraRtcEngine());
static agora::rtc::RtcEngineContext ctx;
ctx.appId = "aab8b8f5a8cd4469a63042fcfafe7063";
ctx.eventHandler = new agora::rtc::IRtcEngineEventHandler();
int ret = RtcEnginePtr->initialize(ctx);
if (ret < 0)
{
UE_LOG(LogTemp, Warning, TEXT("RtcEngine initialize ret: %d"), ret);
}
MediaEnginePtr = TSharedPtr<agora::media::ue4::AgoraMediaEngine>(agora::media::ue4::AgoraMediaEngine::Create(RtcEnginePtr.Get()));
}
FString VideoCall::GetVersion() const
{
if (!RtcEnginePtr)
{
return "";
}
int build = 0;
const char* version = RtcEnginePtr->getVersion(&build);
return FString(ANSI_TO_TCHAR(version));
}

创建回调方法

接下来创建回调方法，返回本地和远端的视频帧

//VideoCall.cpp
void VideoCall::RegisterOnLocalFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnFrameCallback)
{
OnLocalFrameCallback = std::move(OnFrameCallback);
}
void VideoCall::RegisterOnRemoteFrameCallback(
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnFrameCallback)
{
OnRemoteFrameCallback = std::move(OnFrameCallback);
}

创建呼叫方法

我们需要利用这个方法来实现“加入频道”和“离开频道”。

增加 StartCall

首先创建 VideoFrameObserver 对象，然后根据你的场景来设置以下回调。

OnLocalFrameCallback：用于 SDK 获取本地摄像头采集到的视频帧。
OnRemoteFrameCallback：用于 SDK 获取远端摄像头采集到的视频帧。

在 InitAgora 的 MediaEngine 对象中通过 registerVideoFrameObserver 方法注册 VideoFrameObserver。为了保证 EncryptionType 和 EncryptionKey 不为空，需要先设置 EncryptionMode 和 EncryptionSecret。然后按照你的需要来设置频道参数，并调用 joinChannel。

//VideoCall.cpp
void VideoCall::StartCall(
const FString& ChannelName,
const FString& EncryptionKey,
const FString& EncryptionType)
{
if (!RtcEnginePtr)
{
return;
}
if (MediaEnginePtr)
{
if (!VideoFrameObserverPtr)
{
VideoFrameObserverPtr = MakeUnique<VideoFrameObserver>();
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnCaptureVideoFrameCallback
= [this](std::uint8_t* buffer, std::uint32_t width, std::uint32_t height, std::uint32_t size)
{
if (OnLocalFrameCallback)
{
OnLocalFrameCallback(buffer, width, height, size);
}
else { UE_LOG(LogTemp, Warning, TEXT("VideoCall OnLocalFrameCallback isn't set")); }
};
VideoFrameObserverPtr->setOnCaptureVideoFrameCallback(std::move(OnCaptureVideoFrameCallback));
std::function<void(std::uint8_t*, std::uint32_t, std::uint32_t, std::uint32_t)> OnRenderVideoFrameCallback
= [this](std::uint8_t* buffer, std::uint32_t width, std::uint32_t height, std::uint32_t size)
{
if (OnRemoteFrameCallback)
{
OnRemoteFrameCallback(buffer, width, height, size);
}
else { UE_LOG(LogTemp, Warning, TEXT("VideoCall OnRemoteFrameCallback isn't set")); }
};
VideoFrameObserverPtr->setOnRenderVideoFrameCallback(std::move(OnRenderVideoFrameCallback));
}
MediaEnginePtr->registerVideoFrameObserver(VideoFrameObserverPtr.Get());
}
int nRet = RtcEnginePtr->enableVideo();
if (nRet < 0)
{
UE_LOG(LogTemp, Warning, TEXT("enableVideo : %d"), nRet)
}
if (!EncryptionType.IsEmpty() && !EncryptionKey.IsEmpty())
{
if (EncryptionType == "aes-256")
{
RtcEnginePtr->setEncryptionMode("aes-256-xts");
}
else
{
RtcEnginePtr->setEncryptionMode("aes-128-xts");
}
nRet = RtcEnginePtr->setEncryptionSecret(TCHAR_TO_ANSI(*EncryptionKey));
if (nRet < 0)
{
UE_LOG(LogTemp, Warning, TEXT("setEncryptionSecret : %d"), nRet)
}
}
nRet = RtcEnginePtr->setChannelProfile(agora::rtc::CHANNEL_PROFILE_COMMUNICATION);
if (nRet < 0)
{
UE_LOG(LogTemp, Warning, TEXT("setChannelProfile : %d"), nRet)
}
//"demoChannel1";
std::uint32_t nUID = 0;
nRet = RtcEnginePtr->joinChannel(NULL, TCHAR_TO_ANSI(*ChannelName), NULL, nUID);
if (nRet < 0)
{
UE_LOG(LogTemp, Warning, TEXT("joinChannel ret: %d"), nRet);
}
}

增加 StopCall 功能

根据你的场景需要，通过调用 leaveChannel 方法来结束通话，比如当要结束通话的时候，当你需要关闭应用的时候，或是当你的应用运行于后台的时候。调用 nullptr 作为实参的 registerVideoFrameObserver，用来取消 VideoFrameObserver的注册。

//VideoCall.cpp
void VideoCall::StopCall()
{
if (!RtcEnginePtr)
{
return;
}
auto ConnectionState = RtcEnginePtr->getConnectionState();
if (agora::rtc::CONNECTION_STATE_DISCONNECTED != ConnectionState)
{
int nRet = RtcEnginePtr->leaveChannel();
if (nRet < 0)
{
UE_LOG(LogTemp, Warning, TEXT("leaveChannel ret: %d"), nRet);
}
if (MediaEnginePtr)
{
MediaEnginePtr->registerVideoFrameObserver(nullptr);
}
}
}

创建 Video 方法

这些方法是用来管理视频的。

加 EnableVideo() 方法

EnableVideo() 会启用本示例中的视频。初始化 nRet，值为 0。如果 bEnable 为 true，则通过 RtcEnginePtr->enableVideo() 启用视频。否则，通过 RtcEnginePtr->disableVideo() 关闭视频。

//VideoCall.cpp
bool VideoCall::EnableVideo(bool bEnable)
{
if (!RtcEnginePtr)
{
return false;
}
int nRet = 0;
if (bEnable)
nRet = RtcEnginePtr->enableVideo();
else
nRet = RtcEnginePtr->disableVideo();
return nRet == 0 ? true : false;
}

增加 MuteLocalVideo() 方法

MuteLocalVideo() 方法负责开启或关闭本地视频。在其余方法完成运行之前，需要保证 RtcEnginePtr 不为 nullptr。如果可以成功mute 或 unmute 本地视频，那么把 bLocalVideoMuted 设置为 bMuted。

//VideoCall.cpp
bool VideoCall::MuteLocalVideo(bool bMuted)
{
if (!RtcEnginePtr)
{
return false;
}
int ret = RtcEnginePtr->muteLocalVideoStream(bMuted);
if (ret == 0)
bLocalVideoMuted = bMuted;
return ret == 0 ? true : false;
}

增加 IsLocalVideoMuted() 方法

IsLocalVideoMuted() 方法的作用是，当本地视频开启或关闭的时候，返回 bLocalVideoMuted。

//VideoCall.cpp
bool VideoCall::IsLocalVideoMuted()
{
return bLocalVideoMuted;
}

创建音频相关的方法

这些方法是用来管理音频的。

添加 MuteLocalAudio() 方法

MuteLocalAudio()用于 mute 或 unmute 本地音频：

//VideoCall.cpp
bool VideoCall::MuteLocalAudio(bool bMuted)
{
if (!RtcEnginePtr)
{
return false;
}
int ret = RtcEnginePtr->muteLocalAudioStream(bMuted);
if (ret == 0)
bLocalAudioMuted = bMuted;
return ret == 0 ? true : false;
}

增加 IsLocalAudioMuted() 方法

IsLocalAudioMuted()方法的作用是，当 mute 或 unmute 本地音频的时候，返回 bLocalAudioMuted。

//VideoCall.cpp
bool VideoCall::IsLocalAudioMuted()
{
return bLocalAudioMuted;
}

创建 GUI

接下来就是要为一对一对话创建用户交互界面了，包括：

创建 VideoCallPlayerController
创建 EnterChannelWidget C++ Class
创建 VideoViewWidget C++ Class
创建 VideoCallViewWidget C++ Class
创建 VideoCallWidget C++ Class
创建 BP_EnterChannelWidget blueprint asset
创建 BP_VideoViewWidget Asset
创建 BP_VideoCallViewWidget Asset
创建 BP_VideoCallWidget Asset
创建 BP_VideoCallPlayerController blueprint asset
创建 BP_AgoraVideoCallGameModeBase Asset
修改 Game Mode

创建 VideoCallPlayerController

为了能够将我们的Widget Blueprints添加到Viewport中，我们创建我们的自定义播放器控制器类。

在 "内容浏览器 "中，按 "Add New "按钮，选择 "新建C++类"。在 "添加C++类 "窗口中，勾选 "显示所有类 "按钮，并输入PlayerController。按 "下一步 "按钮，给类命名为 VideoCallPlayerController。按Create Class按钮。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

//VideoCallPlayerController.h
#include "CoreMinimal.h"
#include "GameFramework/PlayerController.h"
#include "VideoCallPlayerController.generated.h"
UCLASS()
class AGORAVIDEOCALL_API AVideoCallPlayerController : public APlayerController
{
GENERATED_BODY()
public:
};

这个类是 BP_VideoCallPlayerController 的 Blueprint Asset 的基类，我们将在最后创建。

增加需要的 Include

在 VideoCallPlayerController.h 文件的头部包括了所需的头文件。

//VideoCallPlayerController.h
#include "CoreMinimal.h"
#include "GameFramework/PlayerController.h"
#include "Templates/UniquePtr.h"
#include "VideoCall.h"
#include "VideoCallPlayerController.generated.h"
//VideoCallPlayerController.cpp
#include "Blueprint/UserWidget.h"
#include "EnterChannelWidget.h"
#include "VideoCallWidget.h"

类声明

为下一个类添加转发声明：

//VideoCallPlayerController.h
class UEnterChannelWidget;
class UVideoCallWidget;

稍后我们将跟进其中的两个创建，即 UEnterChannelWidget 和 UVideoCallWidget。

添加成员变量

现在，在编辑器中添加成员引用到 UMG Asset 中。

//VideoCallPlayerController.h
...
UCLASS()
class AGORAVIDEOCALL_API AVideoCallPlayerController : public APlayerController
{
GENERATED_BODY()
public:
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Widgets")
TSubclassOf<class UUserWidget> wEnterChannelWidget;
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Widgets")
TSubclassOf<class UUserWidget> wVideoCallWidget;
...
};

变量来保持创建后的小部件，以及一个指向VideoCall的指针。

//VideoCallPlayerController.h
...
UCLASS()
class AGORAVIDEOCALL_API AVideoCallPlayerController : public APlayerController
{
GENERATED_BODY()
public:
...
UEnterChannelWidget* EnterChannelWidget = nullptr;
UVideoCallWidget* VideoCallWidget = nullptr;
TUniquePtr<VideoCall> VideoCallPtr;
...
};

覆盖 BeginPlay/EndPlay

//VideoCallPlayerController.h
...
UCLASS()
class AGORAVIDEOCALL_API AVideoCallPlayerController : public APlayerController
{
GENERATED_BODY()

public:
...
void BeginPlay() override;
void EndPlay(const EEndPlayReason::Type EndPlayReason) override;
...
};
//VideoCallPlayerController.cpp
void AVideoCallPlayerController::BeginPlay()
{
Super::BeginPlay();
//initialize wigets
if (wEnterChannelWidget) // Check if the Asset is assigned in the blueprint.
{
// Create the widget and store it.
if (!EnterChannelWidget)
{
EnterChannelWidget = CreateWidget<UEnterChannelWidget>(this, wEnterChannelWidget);
EnterChannelWidget->SetVideoCallPlayerController(this);
}
// now you can use the widget directly since you have a referance for it.
// Extra check to make sure the pointer holds the widget.
if (EnterChannelWidget)
{
//let add it to the view port
EnterChannelWidget->AddToViewport();
}
//Show the Cursor.
bShowMouseCursor = true;
}
if (wVideoCallWidget)
{
if (!VideoCallWidget)
{
VideoCallWidget = CreateWidget<UVideoCallWidget>(this, wVideoCallWidget);
VideoCallWidget->SetVideoCallPlayerController(this);
}
if (VideoCallWidget)
{
VideoCallWidget->AddToViewport();
}
VideoCallWidget->SetVisibility(ESlateVisibility::Collapsed);
}
//create video call and switch on the EnterChannelWidget
VideoCallPtr = MakeUnique<VideoCall>();
FString Version = VideoCallPtr->GetVersion();
Version = "Agora version: " + Version;
EnterChannelWidget->UpdateVersionText(Version);
SwitchOnEnterChannelWidget(std::move(VideoCallPtr));
}
void AVideoCallPlayerController::EndPlay(const EEndPlayReason::Type EndPlayReason)
{
Super::EndPlay(EndPlayReason);
}

这时你可能注意到EnterChannelWidget和VideoCallWidget方法被标记为错误，那是因为它们还没有实现。我们将在接下来的步骤中实现它们。

增加 StartCall/EndCall

//VideoCallPlayerController.h
...
UCLASS()
class AGORAVIDEOCALL_API AVideoCallPlayerController : public APlayerController
{
GENERATED_BODY()
public:
...
void StartCall(
TUniquePtr<VideoCall> PassedVideoCallPtr,
const FString& ChannelName,
const FString& EncryptionKey,
const FString& EncryptionType
);
void EndCall(TUniquePtr<VideoCall> PassedVideoCallPtr);
...
};
//VideoCallPlayerController.cpp
void AVideoCallPlayerController::StartCall(
TUniquePtr<VideoCall> PassedVideoCallPtr,
const FString& ChannelName,
const FString& EncryptionKey,
const FString& EncryptionType)
{
SwitchOnVideoCallWidget(std::move(PassedVideoCallPtr));
VideoCallWidget->OnStartCall(
ChannelName,
EncryptionKey,
EncryptionType);
}
void AVideoCallPlayerController::EndCall(TUniquePtr<VideoCall> PassedVideoCallPtr)
{
SwitchOnEnterChannelWidget(std::move(PassedVideoCallPtr));
}

增加打开另一个小工具的方法

//VideoCallPlayerController.h
...
UCLASS()
class AGORAVIDEOCALL_API AVideoCallPlayerController : public APlayerController
{
GENERATED_BODY()
public:
...
void SwitchOnEnterChannelWidget(TUniquePtr<VideoCall> PassedVideoCallPtr);
void SwitchOnVideoCallWidget(TUniquePtr<VideoCall> PassedVideoCallPtr);
...
};
//VideoCallPlayerController.cpp
void AVideoCallPlayerController::SwitchOnEnterChannelWidget(TUniquePtr<VideoCall> PassedVideoCallPtr)
{
if (!EnterChannelWidget)
{
return;
}
EnterChannelWidget->SetVideoCall(std::move(PassedVideoCallPtr));
EnterChannelWidget->SetVisibility(ESlateVisibility::Visible);
}
void AVideoCallPlayerController::SwitchOnVideoCallWidget(TUniquePtr<VideoCall> PassedVideoCallPtr)
{
if (!VideoCallWidget)
{
return;
}
VideoCallWidget->SetVideoCall(std::move(PassedVideoCallPtr));
VideoCallWidget->SetVisibility(ESlateVisibility::Visible);
}

创建 EnterChannelWidget C++类

EnterChannelWidget是负责管理 UI 元素交互的。我们要创建一个新的 UserWidget 类型的类。在内容浏览器中，按Add New按钮，选择New C++类，然后勾选Show All Classes按钮，输入UserWidget。按下 "下一步 "按钮，为类设置一个名称，EnterChannelWidget。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

我们会得到如下代码：

//EnterChannelWidget.h
#include "CoreMinimal.h"
#include "Blueprint/UserWidget.h"
#include "EnterChannelWidget.generated.h"
UCLASS()
class AGORAVIDEOCALL_API UEnterChannelWidget : public UUserWidget
{
GENERATED_BODY()
};

在EnterChannelWidget.h文件中增加一些必要的 include：

//EnterCahnnelWidget.h
#include "CoreMinimal.h"
#include "Blueprint/UserWidget.h"
#include "Components/TextBlock.h"
#include "Components/RichTextBlock.h"
#include "Components/EditableTextBox.h"
#include "Components/ComboBoxString.h"
#include "Components/Button.h"
#include "Components/Image.h"
#include "VideoCall.h"
#include "EnterChannelWidget.generated.h"

class AVideoCallPlayerController;
//EnterCahnnelWidget.cpp
#include "Blueprint/WidgetTree.h"
#include "VideoCallPlayerController.h"

然后我们需要增加如下变量：

//EnterChannelWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UEnterChannelWidget : public UUserWidget
{
GENERATED_BODY()
public:
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UTextBlock* HeaderTextBlock = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UTextBlock* DescriptionTextBlock = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UEditableTextBox* ChannelNameTextBox = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UEditableTextBox* EncriptionKeyTextBox = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UTextBlock* EncriptionTypeTextBlock = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UComboBoxString* EncriptionTypeComboBox = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UButton* JoinButton = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UButton* TestButton = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UButton* VideoSettingsButton = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UTextBlock* ContactsTextBlock = nullptr;
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, meta = (BindWidget))
UTextBlock* BuildInfoTextBlock = nullptr;
...
};

这些变量用来公职 blueprint asset 中相关的 UI 元素。这里最重要的是 BindWidget 元属性。通过将指向小部件的指针标记为 BindWidget，你可以在你的 C++类的 Blueprint 子类中创建一个同名的小部件，并在运行时从 C++中访问它。

同时，还要添加如下成员：

//EnterChannelWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UEnterChannelWidget : public UUserWidget
{
GENERATED_BODY()
...
public:
AVideoCallPlayerController* PlayerController = nullptr;
TUniquePtr<VideoCall> VideoCallPtr;
...
};

添加 Constructor 和 Construct/Destruct 方法

//EnterChannelWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UEnterChannelWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
UEnterChannelWidget(const FObjectInitializer& objectInitializer);
void NativeConstruct() override;
...
};
//EnterChannelWidget.cpp
UEnterChannelWidget::UEnterChannelWidget(const FObjectInitializer& objectInitializer)
: Super(objectInitializer)
{
}
void UEnterChannelWidget::NativeConstruct()
{
Super::NativeConstruct();
if (HeaderTextBlock)
HeaderTextBlock->SetText(FText::FromString("Enter a conference room name"));
if (DescriptionTextBlock)
DescriptionTextBlock->SetText(FText::FromString("If you are the first person to specify this name, \
the room will be created and you will\nbe placed in it. \
If it has already been created you will join the conference in progress"));
if (ChannelNameTextBox)
ChannelNameTextBox->SetHintText(FText::FromString("Channel Name"));
if (EncriptionKeyTextBox)
EncriptionKeyTextBox->SetHintText(FText::FromString("Encription Key"));
if (EncriptionTypeTextBlock)
EncriptionTypeTextBlock->SetText(FText::FromString("Enc Type:"));
if (EncriptionTypeComboBox)
{
EncriptionTypeComboBox->AddOption("aes-128");
EncriptionTypeComboBox->AddOption("aes-256");
EncriptionTypeComboBox->SetSelectedIndex(0);
}
if (JoinButton)
{
UTextBlock* JoinTextBlock = WidgetTree->ConstructWidget<UTextBlock>(UTextBlock::StaticClass());
JoinTextBlock->SetText(FText::FromString("Join"));
JoinButton->AddChild(JoinTextBlock);
JoinButton->OnClicked.AddDynamic(this, &UEnterChannelWidget::OnJoin);
}
if (ContactsTextBlock)
ContactsTextBlock->SetText(FText::FromString("agora.io Contact support: 400 632 6626"));
if (BuildInfoTextBlock)
BuildInfoTextBlock->SetText(FText::FromString(" "));
}

增加 Setter 方法

初始化 PlayerController 和 VideoCallPtr 变量

//EnterChannelWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UEnterChannelWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void SetVideoCallPlayerController(AVideoCallPlayerController* VideoCallPlayerController);
void SetVideoCall(TUniquePtr<VideoCall> PassedVideoCallPtr);
...
};
//EnterChannelWidget.cpp
void UEnterChannelWidget::SetVideoCallPlayerController(AVideoCallPlayerController* VideoCallPlayerController)
{
PlayerController = VideoCallPlayerController;
}
void UEnterChannelWidget::SetVideoCall(TUniquePtr<VideoCall> PassedVideoCallPtr)
{
VideoCallPtr = std::move(PassedVideoCallPtr);
}

增加 BlueprintCallable方法

要对相应的按钮 "onButtonClick "事件做出反应。

//EnterChannelWidget.h
..
UCLASS()
class AGORAVIDEOCALL_API UEnterChannelWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
UFUNCTION(BlueprintCallable)
void OnJoin();
...
};
//EnterChannelWidget.cpp
void UEnterChannelWidget::OnJoin()
{
if (!PlayerController || !VideoCallPtr)
{
return;
}
FString ChannelName = ChannelNameTextBox->GetText().ToString();
FString EncryptionKey = EncriptionKeyTextBox->GetText().ToString();
FString EncryptionType = EncriptionTypeComboBox->GetSelectedOption();
SetVisibility(ESlateVisibility::Collapsed);
PlayerController->StartCall(
std::move(VideoCallPtr),
ChannelName,
EncryptionKey,
EncryptionType);
}

增加 update 方法

//EnterChannelWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UEnterChannelWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void UpdateVersionText(FString newValue);
...
};
//EnterChannelWidget.cpp
void UEnterChannelWidget::UpdateVersionText(FString newValue)
{
if (BuildInfoTextBlock)
BuildInfoTextBlock->SetText(FText::FromString(newValue));
}

创建 VideoViewWidget C++ 类

VideoViewWidget是一个存储动态纹理并使用RGBA buffer 更新动态纹理的类，该类是从VideoCall OnLocalFrameCallback/OnRemoteFrameCallback函数中接收到的。

创建类和添加所需的 include

//VideoViewWidget.h
#include "CoreMinimal.h"
#include "Blueprint/UserWidget.h"
#include "Components/Image.h"
#include "VideoViewWidget.generated.h"
//VideoViewWidget.cpp
#include "EngineUtils.h"
#include "Engine/Texture2D.h"
#include <algorithm>

添加成员变量

Buffer：用于存储RGBA缓冲区、Width、Height和BufferSize的变量 - 视频帧的参数。
RenderTargetImage：允许你在UI中显示Slate Brush或纹理或材质的图像小部件。
RenderTargetTexture：动态纹理，我们将使用Buffer变量更新。

FUpdateTextureRegion2D：指定一个纹理的更新区域刷子 - 一个包含如何绘制Slate元素的笔刷。我们将用它来绘制RenderTargetImage上的RenderTargetTexture。

//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
UImage* RenderTargetImage = nullptr;
UPROPERTY(EditDefaultsOnly)
UTexture2D* RenderTargetTexture = nullptr;
UTexture2D* CameraoffTexture = nullptr;
uint8* Buffer = nullptr;
uint32_t Width = 0;
uint32_t Height = 0;
uint32 BufferSize = 0;
FUpdateTextureRegion2D* UpdateTextureRegion = nullptr;
FSlateBrush Brush;
FCriticalSection Mutex;
...
};

覆盖 NativeConstruct() 方法

在NativeConstruct中，我们将用默认颜色初始化我们的图像。为了初始化我们的RenderTargetTexture，我们需要使用CreateTransient调用创建动态纹理（Texture2D）。然后分配BufferSize为Width * Height * 4的BufferSize（用于存储RGBA格式，每个像素可以用4个字节表示）。为了更新我们的纹理，我们可以使用UpdateTextureRegions函数。这个函数的输入参数之一是我们的像素数据缓冲区。这样，每当我们修改像素数据缓冲区时，我们就需要调用这个函数来使变化在纹理中可见。现在用我们的RenderTargetTexture初始化Brush变量，然后在RenderTargetImage widget中设置这个Brush。

//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void NativeConstruct() override;
...
};
//VideoViewWidget.cpp
void UVideoViewWidget::NativeConstruct()
{
Super::NativeConstruct();
Width = 640;
Height = 360;
RenderTargetTexture = UTexture2D::CreateTransient(Width, Height, PF_R8G8B8A8);
RenderTargetTexture->UpdateResource();
BufferSize = Width * Height * 4;
Buffer = new uint8[BufferSize];
for (uint32 i = 0; i < Width * Height; ++i)
{
Buffer[i * 4 + 0] = 0x32;
Buffer[i * 4 + 1] = 0x32;
Buffer[i * 4 + 2] = 0x32;
Buffer[i * 4 + 3] = 0xFF;
}
UpdateTextureRegion = new FUpdateTextureRegion2D(0, 0, 0, 0, Width, Height);
RenderTargetTexture->UpdateTextureRegions(0, 1, UpdateTextureRegion, Width * 4, (uint32)4, Buffer);
Brush.SetResourceObject(RenderTargetTexture);
RenderTargetImage->SetBrush(Brush);
}

覆盖 NativeDestruct() 方法

//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void NativeDestruct() override;
...
};
//VideoViewWidget.cpp
void UVideoViewWidget::NativeDestruct()
{
Super::NativeDestruct();
delete[] Buffer;
delete UpdateTextureRegion;
}

覆盖 NativeTick() 方法

如果UpdateTextureRegion Width或Height不等于memember的Width Height值，我们需要重新创建RenderTargetTexture以支持更新的值，并像Native Construct成员一样重复初始化。否则只需用Buffer调用UpdateTextureRegions。

//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void NativeTick(const FGeometry& MyGeometry, float DeltaTime) override;
...
};
//VideoViewWidget.cpp
void UVideoViewWidget::NativeTick(const FGeometry& MyGeometry, float DeltaTime)
{
Super::NativeTick(MyGeometry, DeltaTime);
FScopeLock lock(&Mutex);
if (UpdateTextureRegion->Width != Width ||
UpdateTextureRegion->Height != Height)
{
auto NewUpdateTextureRegion = new FUpdateTextureRegion2D(0, 0, 0, 0, Width, Height);
auto NewRenderTargetTexture = UTexture2D::CreateTransient(Width, Height, PF_R8G8B8A8);
NewRenderTargetTexture->UpdateResource();
NewRenderTargetTexture->UpdateTextureRegions(0, 1, NewUpdateTextureRegion, Width * 4, (uint32)4, Buffer);
Brush.SetResourceObject(NewRenderTargetTexture);
RenderTargetImage->SetBrush(Brush);
//UClass's such as UTexture2D are automatically garbage collected when there is no hard pointer references made to that object.
//So if you just leave it and don't reference it elsewhere then it will be destroyed automatically.
FUpdateTextureRegion2D* TmpUpdateTextureRegion = UpdateTextureRegion;
RenderTargetTexture = NewRenderTargetTexture;
UpdateTextureRegion = NewUpdateTextureRegion;
delete TmpUpdateTextureRegion;
return;
}
RenderTargetTexture->UpdateTextureRegions(0, 1, UpdateTextureRegion, Width * 4, (uint32)4, Buffer);
}

增加 UpdateBuffer() 方法

通过调用来更新 Buffer 值。我们希望从 Agora SDK 线程接收到新的值。由于 UE4 的限制，我们将值保存到变量 Buffer 中，并在 NativeTick 方法中更新纹理，所以这里不调用UpdateTextureRegions。

//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void UpdateBuffer( uint8* RGBBuffer, uint32_t Width, uint32_t Height, uint32_t Size );
void ResetBuffer();
...
};
//VideoViewWidget.cpp
void UVideoViewWidget::UpdateBuffer(
uint8* RGBBuffer,
uint32_t NewWidth,
uint32_t NewHeight,
uint32_t NewSize)
{
FScopeLock lock(&Mutex);
if (!RGBBuffer)
{
return;
}
if (BufferSize == NewSize)
{
std::copy(RGBBuffer, RGBBuffer + NewSize, Buffer);
}
else
{
delete[] Buffer;
BufferSize = NewSize;
Width = NewWidth;
Height = NewHeight;
Buffer = new uint8[BufferSize];
std::copy(RGBBuffer, RGBBuffer + NewSize, Buffer);
}
}
void UVideoViewWidget::ResetBuffer()
{
for (uint32 i = 0; i < Width * Height; ++i)
{
Buffer[i * 4 + 0] = 0x32;
Buffer[i * 4 + 1] = 0x32;
Buffer[i * 4 + 2] = 0x32;
Buffer[i * 4 + 3] = 0xFF;
}
}

创建 VideoCallViewWidget C++类

VideoCallViewWidget 类的作用是显示本地和远程用户的视频。我们需要两个 VideoViewWidget 小部件，一个用来显示来自本地摄像头的视频，另一个用来显示从远程用户收到的视频（假设我们只支持一个远程用户）。

创建类和添加所需的 include

像之前那样创建Widget C++类，添加所需的include。

//VideoCallViewWidget.h
#include "CoreMinimal.h"
#include "Blueprint/UserWidget.h"
#include "Components/SizeBox.h"
#include "VideoViewWidget.h"
#include "VideoCallViewWidget.generated.h"
//VideoCallViewWidget.cpp
#include "Components/CanvasPanelSlot.h"

添加成员变量

//VideoCallViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
UVideoViewWidget* MainVideoViewWidget = nullptr;
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
USizeBox* MainVideoSizeBox = nullptr;
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
UVideoViewWidget* AdditionalVideoViewWidget = nullptr;
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
USizeBox* AdditionalVideoSizeBox = nullptr;
public:
int32 MainVideoWidth = 0;
int32 MainVideoHeight = 0;
...
};

覆盖 NativeTick() 方法

``
//VideoCallViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void NativeTick(const FGeometry& MyGeometry, float DeltaTime) override;
...
};
//VideoCallViewWidget.cpp
void UVideoCallViewWidget::NativeTick(const FGeometry& MyGeometry, float DeltaTime)
{
Super::NativeTick(MyGeometry, DeltaTime);
auto ScreenSize = MyGeometry.GetLocalSize();
if (MainVideoHeight != 0)
{
float AspectRatio = 0;
AspectRatio = MainVideoWidth / (float)MainVideoHeight;
auto MainVideoGeometry = MainVideoViewWidget->GetCachedGeometry();
auto MainVideoScreenSize = MainVideoGeometry.GetLocalSize();
if (MainVideoScreenSize.X == 0)
{
return;
}
auto NewMainVideoHeight = MainVideoScreenSize.Y;
auto NewMainVideoWidth = AspectRatio * NewMainVideoHeight;
MainVideoSizeBox->SetMinDesiredWidth(NewMainVideoWidth);
MainVideoSizeBox->SetMinDesiredHeight(NewMainVideoHeight);
UCanvasPanelSlot* CanvasSlot = Cast<UCanvasPanelSlot>(MainVideoSizeBox->Slot);
CanvasSlot->SetAutoSize(true);
FVector2D NewPosition;
NewPosition.X = -NewMainVideoWidth / 2;
NewPosition.Y = -NewMainVideoHeight / 2;
CanvasSlot->SetPosition(NewPosition);
}
}

更新 UpdateMainVideoBuffer/UpdateAdditionalVideoBuffe

//VideoCallViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void UpdateMainVideoBuffer( uint8* RGBBuffer, uint32_t Width, uint32_t Height, uint32_t Size);
void UpdateAdditionalVideoBuffer( uint8* RGBBuffer, uint32_t Width, uint32_t Height, uint32_t Size);
void ResetBuffers();
...
};
//VideoCallViewWidget.cpp
void UVideoCallViewWidget::UpdateMainVideoBuffer(
uint8* RGBBuffer,
uint32_t Width,
uint32_t Height,
uint32_t Size)
{
if (!MainVideoViewWidget)
{
return;
}
MainVideoWidth = Width;
MainVideoHeight = Height;
MainVideoViewWidget->UpdateBuffer(RGBBuffer, Width, Height, Size);
}
void UVideoCallViewWidget::UpdateAdditionalVideoBuffer(
uint8* RGBBuffer,
uint32_t Width,
uint32_t Height,
uint32_t Size)
{
if (!AdditionalVideoViewWidget)
{
return;
}
AdditionalVideoViewWidget->UpdateBuffer(RGBBuffer, Width, Height, Size);
}
void UVideoCallViewWidget::ResetBuffers()
{
if (!MainVideoViewWidget || !AdditionalVideoViewWidget)
{
return;
}
MainVideoViewWidget->ResetBuffer();
AdditionalVideoViewWidget->ResetBuffer();
}

创建 VideoCallWidget C++ 类

VideoCallWidget 类作为示例应用程序的音频/视频调用小部件。它包含以下控件，与蓝图资产中的UI元素绑定。

创建类和添加所需的include

像之前那样创建Widget C++类，添加必要的include和转发声明。

//VideoCallWidget.h
#include "CoreMinimal.h"
#include "Blueprint/UserWidget.h"
#include "Templates/UniquePtr.h"
#include "Components/Image.h"
#include "Components/Button.h"
#include "Engine/Texture2D.h"
#include "VideoCall.h"
#include "VideoCallViewWidget.h"
#include "VideoCallWidget.generated.h"
class AVideoCallPlayerController;
class UVideoViewWidget;
//VideoCallWidget.cpp
#include "Kismet/GameplayStatics.h"
#include "UObject/ConstructorHelpers.h"
#include "Components/CanvasPanelSlot.h"
#include "VideoViewWidget.h"
#include "VideoCallPlayerController.h"

增加成员变量

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
public:
AVideoCallPlayerController* PlayerController = nullptr;
public:
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
UVideoCallViewWidget* VideoCallViewWidget = nullptr;
//Buttons
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
UButton* EndCallButton = nullptr;
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
UButton* MuteLocalAudioButton = nullptr;
UPROPERTY(BlueprintReadOnly, meta = (BindWidget))
UButton* VideoModeButton = nullptr;
//Button textures
int32 ButtonSizeX = 96;
int32 ButtonSizeY = 96;
UTexture2D* EndCallButtonTexture = nullptr;
UTexture2D* AudioButtonMuteTexture = nullptr;
UTexture2D* AudioButtonUnmuteTexture = nullptr;
UTexture2D* VideomodeButtonCameraoffTexture = nullptr;
UTexture2D* VideomodeButtonCameraonTexture = nullptr;
TUniquePtr<VideoCall> VideoCallPtr;
...
};

初始化VideoCallWidget

为每个按钮找到asset图像，并将其分配到相应的纹理。然后用纹理初始化每个按钮。

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
public:
..
UVideoCallWidget(const FObjectInitializer& ObjectInitializer);
void NativeConstruct() override;
void NativeDestruct() override;
private:
void InitButtons();
...
};
//VideoCallWidget.cpp
void UVideoCallWidget::NativeConstruct()
{
Super::NativeConstruct();
InitButtons();
}
void UVideoCallWidget::NativeDestruct()
{
Super::NativeDestruct();
if (VideoCallPtr)
{
VideoCallPtr->StopCall();
}
}
UVideoCallWidget::UVideoCallWidget(const FObjectInitializer& ObjectInitializer)
: Super(ObjectInitializer)
{
static ConstructorHelpers::FObjectFinder<UTexture2D>
EndCallButtonTextureFinder(TEXT("Texture'/Game/ButtonTextures/hangup.hangup'"));
if (EndCallButtonTextureFinder.Succeeded())
{
EndCallButtonTexture = EndCallButtonTextureFinder.Object;
}
static ConstructorHelpers::FObjectFinder<UTexture2D>
AudioButtonMuteTextureFinder(TEXT("Texture'/Game/ButtonTextures/mute.mute'"));
if (AudioButtonMuteTextureFinder.Succeeded())
{
AudioButtonMuteTexture = AudioButtonMuteTextureFinder.Object;
}
static ConstructorHelpers::FObjectFinder<UTexture2D>
AudioButtonUnmuteTextureFinder(TEXT("Texture'/Game/ButtonTextures/unmute.unmute'"));
if (AudioButtonUnmuteTextureFinder.Succeeded())
{
AudioButtonUnmuteTexture = AudioButtonUnmuteTextureFinder.Object;
}
static ConstructorHelpers::FObjectFinder<UTexture2D>
VideomodeButtonCameraonTextureFinder(TEXT("Texture'/Game/ButtonTextures/cameraon.cameraon'"));
if (VideomodeButtonCameraonTextureFinder.Succeeded())
{
VideomodeButtonCameraonTexture = VideomodeButtonCameraonTextureFinder.Object;
}
static ConstructorHelpers::FObjectFinder<UTexture2D>
VideomodeButtonCameraoffTextureFinder(TEXT("Texture'/Game/ButtonTextures/cameraoff.cameraoff'"));
if (VideomodeButtonCameraoffTextureFinder.Succeeded())
{
VideomodeButtonCameraoffTexture = VideomodeButtonCameraoffTextureFinder.Object;
}
}
void UVideoCallWidget::InitButtons()
{
if (EndCallButtonTexture)
{
EndCallButton->WidgetStyle.Normal.SetResourceObject(EndCallButtonTexture);
EndCallButton->WidgetStyle.Normal.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
EndCallButton->WidgetStyle.Normal.DrawAs = ESlateBrushDrawType::Type::Image;
EndCallButton->WidgetStyle.Hovered.SetResourceObject(EndCallButtonTexture);
EndCallButton->WidgetStyle.Hovered.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
EndCallButton->WidgetStyle.Hovered.DrawAs = ESlateBrushDrawType::Type::Image;
EndCallButton->WidgetStyle.Pressed.SetResourceObject(EndCallButtonTexture);
EndCallButton->WidgetStyle.Pressed.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
EndCallButton->WidgetStyle.Pressed.DrawAs = ESlateBrushDrawType::Type::Image;
}
EndCallButton->OnClicked.AddDynamic(this, &UVideoCallWidget::OnEndCall);
SetAudioButtonToMute();
MuteLocalAudioButton->OnClicked.AddDynamic(this, &UVideoCallWidget::OnMuteLocalAudio);
SetVideoModeButtonToCameraOff();
VideoModeButton->OnClicked.AddDynamic(this, &UVideoCallWidget::OnChangeVideoMode);
}

添加按钮纹理

在演示程序中找到目录Content/ButtonTextures（你不必打开项目，只需在文件系统中找到这个文件夹即可）。所有的按钮纹理都存储在那里。在你的项目内容中创建一个名为ButtonTextures的新目录，将所有的按钮图片拖放到那里，让它们在你的项目中可用。

添加Setters

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
...
public:
void SetVideoCallPlayerController(AVideoCallPlayerController* VideoCallPlayerController);
void SetVideoCall(TUniquePtr<VideoCall> PassedVideoCallPtr);
...
};
//VideoCallWidget.cpp
void UVideoCallWidget::SetVideoCallPlayerController(AVideoCallPlayerController* VideoCallPlayerController)
{
PlayerController = VideoCallPlayerController;
}
void UVideoCallWidget::SetVideoCall(TUniquePtr<VideoCall> PassedVideoCallPtr)
{
VideoCallPtr = std::move(PassedVideoCallPtr);
}

增加用来更新 view 的方法

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
...
private:
void SetVideoModeButtonToCameraOff();
void SetVideoModeButtonToCameraOn();
void SetAudioButtonToMute();
void SetAudioButtonToUnMute();
...
};
//VideoCallWidget.cpp
void UVideoCallWidget::SetVideoModeButtonToCameraOff()
{
if (VideomodeButtonCameraoffTexture)
{
VideoModeButton->WidgetStyle.Normal.SetResourceObject(VideomodeButtonCameraoffTexture);
VideoModeButton->WidgetStyle.Normal.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
VideoModeButton->WidgetStyle.Normal.DrawAs = ESlateBrushDrawType::Type::Image;
VideoModeButton->WidgetStyle.Hovered.SetResourceObject(VideomodeButtonCameraoffTexture);
VideoModeButton->WidgetStyle.Hovered.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
VideoModeButton->WidgetStyle.Hovered.DrawAs = ESlateBrushDrawType::Type::Image;
VideoModeButton->WidgetStyle.Pressed.SetResourceObject(VideomodeButtonCameraoffTexture);
VideoModeButton->WidgetStyle.Pressed.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
VideoModeButton->WidgetStyle.Pressed.DrawAs = ESlateBrushDrawType::Type::Image;
}
}
void UVideoCallWidget::SetVideoModeButtonToCameraOn()
{
if (VideomodeButtonCameraonTexture)
{
VideoModeButton->WidgetStyle.Normal.SetResourceObject(VideomodeButtonCameraonTexture);
VideoModeButton->WidgetStyle.Normal.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
VideoModeButton->WidgetStyle.Normal.DrawAs = ESlateBrushDrawType::Type::Image;
VideoModeButton->WidgetStyle.Hovered.SetResourceObject(VideomodeButtonCameraonTexture);
VideoModeButton->WidgetStyle.Hovered.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
VideoModeButton->WidgetStyle.Hovered.DrawAs = ESlateBrushDrawType::Type::Image;
VideoModeButton->WidgetStyle.Pressed.SetResourceObject(VideomodeButtonCameraonTexture);
VideoModeButton->WidgetStyle.Pressed.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
VideoModeButton->WidgetStyle.Pressed.DrawAs = ESlateBrushDrawType::Type::Image;
}
}
void UVideoCallWidget::SetAudioButtonToMute()
{
if (AudioButtonMuteTexture)
{
MuteLocalAudioButton->WidgetStyle.Normal.SetResourceObject(AudioButtonMuteTexture);
MuteLocalAudioButton->WidgetStyle.Normal.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
MuteLocalAudioButton->WidgetStyle.Normal.DrawAs = ESlateBrushDrawType::Type::Image;
MuteLocalAudioButton->WidgetStyle.Hovered.SetResourceObject(AudioButtonMuteTexture);
MuteLocalAudioButton->WidgetStyle.Hovered.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
MuteLocalAudioButton->WidgetStyle.Hovered.DrawAs = ESlateBrushDrawType::Type::Image;
MuteLocalAudioButton->WidgetStyle.Pressed.SetResourceObject(AudioButtonMuteTexture);
MuteLocalAudioButton->WidgetStyle.Pressed.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
MuteLocalAudioButton->WidgetStyle.Pressed.DrawAs = ESlateBrushDrawType::Type::Image;
}
}
void UVideoCallWidget::SetAudioButtonToUnMute()
{
if (AudioButtonUnmuteTexture)
{
MuteLocalAudioButton->WidgetStyle.Normal.SetResourceObject(AudioButtonUnmuteTexture);
MuteLocalAudioButton->WidgetStyle.Normal.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
MuteLocalAudioButton->WidgetStyle.Normal.DrawAs = ESlateBrushDrawType::Type::Image;
MuteLocalAudioButton->WidgetStyle.Hovered.SetResourceObject(AudioButtonUnmuteTexture);
MuteLocalAudioButton->WidgetStyle.Hovered.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
MuteLocalAudioButton->WidgetStyle.Hovered.DrawAs = ESlateBrushDrawType::Type::Image;
MuteLocalAudioButton->WidgetStyle.Pressed.SetResourceObject(AudioButtonUnmuteTexture);
MuteLocalAudioButton->WidgetStyle.Pressed.ImageSize = FVector2D(ButtonSizeX, ButtonSizeY);
MuteLocalAudioButton->WidgetStyle.Pressed.DrawAs = ESlateBrushDrawType::Type::Image;
}
}

增加 OnStartCall 方法

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void OnStartCall( const FString& ChannelName, const FString& EncryptionKey, const FString& EncryptionType );
...
};
//VideoCallWidget.cpp
void UVideoCallWidget::OnStartCall(
const FString& ChannelName,
const FString& EncryptionKey,
const FString& EncryptionType)
{
if (!VideoCallPtr)
{
return;
}
auto OnLocalFrameCallback = [this](
std::uint8_t* Buffer,
std::uint32_t Width,
std::uint32_t Height,
std::uint32_t Size)
{
VideoCallViewWidget->UpdateAdditionalVideoBuffer(Buffer, Width, Height, Size);
};
VideoCallPtr->RegisterOnLocalFrameCallback(OnLocalFrameCallback);
auto OnRemoteFrameCallback = [this](
std::uint8_t* Buffer,
std::uint32_t Width,
std::uint32_t Height,
std::uint32_t Size)
{
VideoCallViewWidget->UpdateMainVideoBuffer(Buffer, Width, Height, Size);
};
VideoCallPtr->RegisterOnRemoteFrameCallback(OnRemoteFrameCallback);
VideoCallPtr->StartCall(ChannelName, EncryptionKey, EncryptionType);
}

增加 OnEndCall方法

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
UFUNCTION(BlueprintCallable)
void OnEndCall();
...
};
//VideoCallWidget.cpp
void UVideoCallWidget::OnEndCall()
{
if (VideoCallPtr)
{
VideoCallPtr->StopCall();
}
if (VideoCallViewWidget)
{
VideoCallViewWidget->ResetBuffers();
}
if (PlayerController)
{
SetVisibility(ESlateVisibility::Collapsed);
PlayerController->EndCall(std::move(VideoCallPtr));
}
}

增加 OnMuteLocalAudio 方法

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
UFUNCTION(BlueprintCallable)
void OnMuteLocalAudio();
...
};
//VideoCallWidget.cpp
void UVideoCallWidget::OnMuteLocalAudio()
{
if (!VideoCallPtr)
{
return;
}
if (VideoCallPtr->IsLocalAudioMuted())
{
VideoCallPtr->MuteLocalAudio(false);
SetAudioButtonToMute();
}
else
{
VideoCallPtr->MuteLocalAudio(true);
SetAudioButtonToUnMute();
}
}

增加 OnChangeVideoMode方法

//VideoCallWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoCallWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
UFUNCTION(BlueprintCallable)
void OnChangeVideoMode();
...
};
//VideoCallWidget.cpp
void UVideoCallWidget::OnChangeVideoMode()
{
if (!VideoCallPtr)
{
return;
}
if (!VideoCallPtr->IsLocalVideoMuted())
{
VideoCallPtr->MuteLocalVideo(true);
SetVideoModeButtonToCameraOn();
}
else
{
VideoCallPtr->EnableVideo(true);
VideoCallPtr->MuteLocalVideo(false);
SetVideoModeButtonToCameraOff();
}
}

增加 Blueprint 类

确保C++代码正确编译。没有成功编译的项目，你将无法进行下一步的操作。如果你已经成功地编译了C++代码，但在虚幻编辑器中仍然没有看到所需的类，请尝试重新打开项目。

创建 BP_EnterChannelWidget Blueprint Asset。

创建一个 UEnterChannelWidget 的 Blueprint，右键点击内容，选择用户界面菜单并选择 Widget Blueprint。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

更改这个新的用户小工具的类的父类。打开 Blueprint，会出现 UMG 编辑器界面，默认情况下 Designer 选项卡是打开的。点击图形按钮（右上角按钮），选择 "类设置"。在面板 "Details "中，点击下拉列表 "父类"，选择之前创建的C++ 类 UEnterChannelWidget。现在返回到设计页面。调色板窗口包含几种不同类型的小部件，你可以用它们来构造你的 UI 元素。找到 Text、Editable Text、Button 和 ComboBox（String）元素，然后将它们拖到工作区，如图中所示。然后进入 "EnterChannelWidget.h "文件中的 UEnterChannelWidget 的定义，查看成员变量的名称和对应的类型（UTextBlock、EditableTextBox、UButton和UComboBoxString）。返回到 BP_VideoCallWiewVidget 编辑器中，给你拖动的UI元素设置相同的名称。你可以通过点击元素并在 "详细信息 "面板中更改名称来完成。尝试编译蓝图。如果你忘了添加什么东西，或者在你的UserWidget类中出现了widget名称/类型不匹配的情况，你会出现一个错误。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

保存到文件夹中，例如 /Content/Widgets/BP_EnterChannelWidget.uasset。

创建 BP_VideoViewWidget Asset。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

设定图片的锚点

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

创建 BP_VideoCallViewWidget Asset

创建 BP VideoCallViewWidget Asset ，将父类设置为 UVideoCallViewWidget，并添加 BP VideoViewWidget 类型的 UI 元素MainVideoViewWidget 和ExtendedVideoViewWidget。同时添加 SizeBox 类型的 MainVideoSizeBox 和 AdditionalVideoSizeBox UI 元素。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解

创建 BP_VideoCallWidget Asset

创建BPVideoCallWidget Asset，将父类设置为UVideoCallWidget，在 Palette UI 元素BPVideoCallViewWidget 中找到并添加名称为VideoCallViewWidget，添加 EndCallButton、MuteLocalAudioButton 和 VideoModeButton 按钮。

C++ 在 Unreal 中为游戏增加实时音视频互动的教程详解