C++在Unreal中如何為游戲增加實時音視頻互動

發布時間：2020-07-21 17:21:23 來源：億速云閱讀：208 作者：小豬欄目：編程語言

小編這次要給大家分享的是C++在Unreal中如何為游戲增加實時音視頻互動，文章內容豐富，感興趣的小伙伴可以來了解一下，希望大家閱讀完這篇文章之后能夠有所收獲。

我們已經上線了 Agora Unreal SDK，提供了支持 Blueprint 和 C++ 的兩個版本 SDK。我們分享了如何基于 Blueprint 在游戲中創建實時音視頻功能。在本文中，我們來分享如何基于聲網 Agora Unreal SDK C++版本，在游戲中實現實時音視頻功能。

本篇教程較長，建議在 Web 瀏覽器端瀏覽，體驗更好。

準備工作

需要的開發環境和需要準備的與 Blueprint 一樣：

Unreal 4.34 以上版本
Visual Studio 或 Xcode（版本根據 Unreal 配置要求而定）
運行 Windows 7 以上系統的 PC 或一臺 Mac
Agora 注冊賬號一枚（免費注冊，見官網 Agora.io）
如果你的企業網絡存在防火墻，請在聲網文檔中心搜索「應用企業防火墻限制」，進行配置。

新建項目

如果你已經有 Unreal 項目了，可以跳過這一步。在 Unreal 中創建一個 C++類型的項目。

C++在Unreal中如何為游戲增加實時音視頻互動

確保在 [your_project]/Source/[project_name]/[project_name].Build.cs文件的 PrivateDependencyModuleNames一行，去掉注釋。Unreal 默認是將它注釋掉的，這會導致在編譯的時候報錯。

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

接下來我們在項目中集成 Agora SDK

1.將 SDK 復制到這個路徑下 [your_project]/Plugins

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

3.重啟 Unreal

4.點擊 Edit->Plugin，在分類中找到 Project->Other，確定插件已經生效

C++在Unreal中如何為游戲增加實時音視頻互動

創建新的 Level

接下來我們將創建一個新的 Level，在那里建立我們的游戲環境。有幾種不同的方法可以創建一個新的 Level，我們將使用文件菜單的方法，其中列出了關卡選擇選項。

在虛幻編輯器里面，點擊文件菜單選項，然后選擇新建 Level......

C++在Unreal中如何為游戲增加實時音視頻互動

然后會打開一個新的對話框。

C++在Unreal中如何為游戲增加實時音視頻互動

選擇Empty Level ，然后指定一個存儲的路徑。

創建核心類

在這里我們要創建兩個類：VideoFrameObserver 和VideoCall C++ Class。他們會負責與 Agora SDK 進行通信。

首先是 VideoFrameObserver。VideoFrameObserver 執行的是 agora::media::IVideoFrameObserver。這個方法在 VideoFrameObserver 類中負責管理視頻幀的回調。它是用 registerVideoFrameObserver 在 agora::media::IMediaEngine 中注冊的。

在 Unreal 編輯器中，選擇 File->Add New C++ Class。

C++在Unreal中如何為游戲增加實時音視頻互動

父類誰定為 None，然后點擊下一步。

C++在Unreal中如何為游戲增加實時音視頻互動

為 VideoFrameObserver明明，然后選擇 Create Class。

C++在Unreal中如何為游戲增加實時音視頻互動

創建 VideoFrameObserver 類接口。

打開 VideoFrameObserver.h 文件然后添加如下代碼：

//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 是項目依賴的定義，而不是由Unreal 生成的你自己的定義。

重寫onCaptureVideoFrame/onRenderVideoFrame方法

onCaptureVideoFrame 會獲取到攝像頭捕獲的畫面，轉換為 ARGB 格式并觸發 OnCaptureVideoFrame 回調。

onRenderVideoFrame 講收到的特定用戶畫面轉換為 ARGB 格式，然后觸發 onRenderVideoFrame 回調。

//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。

設定回調，用來獲取攝像頭獲取到的本地畫面和遠端的畫面。

//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;
}

創建視頻通話C++類

VideoCall 類管理與 Agora SDK 的通信。需要創建多個方法和接口。

創建類接口

回到 Unreal 編輯器，再創建一個新的 C++類，命名為 VideoCall.h。然后進入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;
};

創建初始化方法

進入 VideoCall.cpp 文件，添加以下代碼：

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

用agora::rtc::ue4::AgoraRtcEngine::createAgoraRtcEngine()創建引擎，初始化 RtcEnginePtr 變量。創建一個RtcEngineContext對象，然后在ctx.eventHandler 和ctx.appId中設定 event handler 和 App ID 。初始化引擎，并創建AgoraMediaEngine對象，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));
}

創建回調方法

接下來創建回調方法，返回本地和遠端的視頻幀

//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);
}

創建呼叫方法

我們需要利用這個方法來實現“加入頻道”和“離開頻道”。

增加 StartCall

首先創建 VideoFrameObserver 對象，然后根據你的場景來設置以下回調。

OnLocalFrameCallback：用于 SDK 獲取本地攝像頭采集到的視頻幀。
OnRemoteFrameCallback：用于 SDK 獲取遠端攝像頭采集到的視頻幀。

在 InitAgora 的 MediaEngine 對象中通過 registerVideoFrameObserver 方法注冊 VideoFrameObserver。為了保證 EncryptionType 和 EncryptionKey 不為空，需要先設置 EncryptionMode 和 EncryptionSecret。然后按照你的需要來設置頻道參數，并調用 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

根據你的場景需要，通過調用 leaveChannel 方法來結束通話，比如當要結束通話的時候，當你需要關閉應用的時候，或是當你的應用運行于后臺的時候。調用 nullptr 作為實參的 registerVideoFrameObserver，用來取消 VideoFrameObserver的注冊。

//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);
 }
 }
}

創建 Video 方法

這些方法是用來管理視頻的。

加 EnableVideo() 方法

EnableVideo() 會啟用本示例中的視頻。初始化 nRet，值為 0。如果 bEnable 為 true，則通過 RtcEnginePtr->enableVideo() 啟用視頻。否則，通過 RtcEnginePtr->disableVideo() 關閉視頻。

//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 &#63; true : false;
}

增加 MuteLocalVideo() 方法

MuteLocalVideo() 方法負責開啟或關閉本地視頻。在其余方法完成運行之前，需要保證 RtcEnginePtr 不為 nullptr。如果可以成功mute 或 unmute 本地視頻，那么把 bLocalVideoMuted 設置為 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 &#63; true : false;
}

增加 IsLocalVideoMuted() 方法

IsLocalVideoMuted() 方法的作用是，當本地視頻開啟或關閉的時候，返回 bLocalVideoMuted。

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

創建音頻相關的方法

這些方法是用來管理音頻的。

添加 MuteLocalAudio() 方法

MuteLocalAudio()用于 mute 或 unmute 本地音頻：

//VideoCall.cpp
bool VideoCall::MuteLocalAudio(bool bMuted)
{
 if (!RtcEnginePtr)
 {
 return false;
 }
 int ret = RtcEnginePtr->muteLocalAudioStream(bMuted);
 if (ret == 0)
 bLocalAudioMuted = bMuted;
 return ret == 0 &#63; true : false;
}

增加 IsLocalAudioMuted() 方法

IsLocalAudioMuted()方法的作用是，當 mute 或 unmute 本地音頻的時候，返回 bLocalAudioMuted。

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

創建 GUI

接下來就是要為一對一對話創建用戶交互界面了，包括：

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

創建 VideoCallPlayerController

為了能夠將我們的Widget Blueprints添加到Viewport中，我們創建我們的自定義播放器控制器類。

在 "內容瀏覽器 "中，按 "Add New "按鈕，選擇 "新建C++類"。在 "添加C++類 "窗口中，勾選 "顯示所有類 "按鈕，并輸入PlayerController。按 "下一步 "按鈕，給類命名為 VideoCallPlayerController。按Create Class按鈕。

C++在Unreal中如何為游戲增加實時音視頻互動

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

這個類是 BP_VideoCallPlayerController 的 Blueprint Asset 的基類，我們將在最后創建。

增加需要的 Include

在 VideoCallPlayerController.h 文件的頭部包括了所需的頭文件。

//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"

類聲明

為下一個類添加轉發聲明：

//VideoCallPlayerController.h
class UEnterChannelWidget;
class UVideoCallWidget;

稍后我們將跟進其中的兩個創建，即 UEnterChannelWidget 和 UVideoCallWidget。

添加成員變量

現在，在編輯器中添加成員引用到 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;
 ...
};

變量來保持創建后的小部件，以及一個指向VideoCall的指針。

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

覆蓋 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);
}

這時你可能注意到EnterChannelWidget和VideoCallWidget方法被標記為錯誤，那是因為它們還沒有實現。我們將在接下來的步驟中實現它們。

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));
}

增加打開另一個小工具的方法

//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);
}

創建 EnterChannelWidget C++類

EnterChannelWidget是負責管理 UI 元素交互的。我們要創建一個新的 UserWidget 類型的類。在內容瀏覽器中，按Add New按鈕，選擇New C++類，然后勾選Show All Classes按鈕，輸入UserWidget。按下 "下一步 "按鈕，為類設置一個名稱，EnterChannelWidget。

C++在Unreal中如何為游戲增加實時音視頻互動

我們會得到如下代碼：

//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"

然后我們需要增加如下變量：

//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;
 ...
};

這些變量用來公職 blueprint asset 中相關的 UI 元素。這里最重要的是 BindWidget 元屬性。通過將指向小部件的指針標記為 BindWidget，你可以在你的 C++類的 Blueprint 子類中創建一個同名的小部件，并在運行時從 C++中訪問它。

同時，還要添加如下成員：

//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 變量

//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

要對相應的按鈕 "onButtonClick "事件做出反應。

//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));
}

創建 VideoViewWidget C++ 類

VideoViewWidget是一個存儲動態紋理并使用RGBA buffer 更新動態紋理的類，該類是從VideoCall OnLocalFrameCallback/OnRemoteFrameCallback函數中接收到的。

創建類和添加所需的 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>

添加成員變量

Buffer：用于存儲RGBA緩沖區、Width、Height和BufferSize的變量 - 視頻幀的參數。
RenderTargetImage：允許你在UI中顯示Slate Brush或紋理或材質的圖像小部件。
RenderTargetTexture：動態紋理，我們將使用Buffer變量更新。

FUpdateTextureRegion2D：指定一個紋理的更新區域刷子 - 一個包含如何繪制Slate元素的筆刷。我們將用它來繪制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;

 ...
};

覆蓋 NativeConstruct() 方法

在NativeConstruct中，我們將用默認顏色初始化我們的圖像。為了初始化我們的RenderTargetTexture，我們需要使用CreateTransient調用創建動態紋理（Texture2D）。然后分配BufferSize為Width * Height * 4的BufferSize（用于存儲RGBA格式，每個像素可以用4個字節表示）。為了更新我們的紋理，我們可以使用UpdateTextureRegions函數。這個函數的輸入參數之一是我們的像素數據緩沖區。這樣，每當我們修改像素數據緩沖區時，我們就需要調用這個函數來使變化在紋理中可見。現在用我們的RenderTargetTexture初始化Brush變量，然后在RenderTargetImage widget中設置這個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);
}

覆蓋 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;
}

覆蓋 NativeTick() 方法

如果UpdateTextureRegion Width或Height不等于memember的Width Height值，我們需要重新創建RenderTargetTexture以支持更新的值，并像Native Construct成員一樣重復初始化。否則只需用Buffer調用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

通過調用來更新 Buffer 值。我們希望從 Agora SDK 線程接收到新的值。由于 UE4 的限制，我們將值保存到變量 Buffer 中，并在 NativeTick 方法中更新紋理，所以這里不調用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;
 }
}

創建 VideoCallViewWidget C++類

VideoCallViewWidget 類的作用是顯示本地和遠程用戶的視頻。我們需要兩個 VideoViewWidget 小部件，一個用來顯示來自本地攝像頭的視頻，另一個用來顯示從遠程用戶收到的視頻（假設我們只支持一個遠程用戶）。

創建類和添加所需的 include

像之前那樣創建Widget C++類，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"

添加成員變量

//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;

 ...
};

覆蓋 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();
}

創建 VideoCallWidget C++ 類

VideoCallWidget 類作為示例應用程序的音頻/視頻調用小部件。它包含以下控件，與藍圖資產中的UI元素綁定。

創建類和添加所需的include

像之前那樣創建Widget C++類，添加必要的include和轉發聲明。

//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"

增加成員變量

//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

為每個按鈕找到asset圖像，并將其分配到相應的紋理。然后用紋理初始化每個按鈕。

//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);

}

添加按鈕紋理

在演示程序中找到目錄Content/ButtonTextures（你不必打開項目，只需在文件系統中找到這個文件夾即可）。所有的按鈕紋理都存儲在那里。在你的項目內容中創建一個名為ButtonTextures的新目錄，將所有的按鈕圖片拖放到那里，讓它們在你的項目中可用。

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);
}

增加用來更新 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 類

確保C++代碼正確編譯。沒有成功編譯的項目，你將無法進行下一步的操作。如果你已經成功地編譯了C++代碼，但在虛幻編輯器中仍然沒有看到所需的類，請嘗試重新打開項目。

創建 BP_EnterChannelWidget Blueprint Asset。

創建一個 UEnterChannelWidget 的 Blueprint，右鍵點擊內容，選擇用戶界面菜單并選擇 Widget Blueprint。

C++在Unreal中如何為游戲增加實時音視頻互動

更改這個新的用戶小工具的類的父類。打開 Blueprint，會出現 UMG 編輯器界面，默認情況下 Designer 選項卡是打開的。點擊圖形按鈕（右上角按鈕），選擇 "類設置"。在面板 "Details "中，點擊下拉列表 "父類"，選擇之前創建的C++ 類 UEnterChannelWidget。現在返回到設計頁面。調色板窗口包含幾種不同類型的小部件，你可以用它們來構造你的 UI 元素。找到 Text、Editable Text、Button 和 ComboBox（String）元素，然后將它們拖到工作區，如圖中所示。然后進入 "EnterChannelWidget.h "文件中的 UEnterChannelWidget 的定義，查看成員變量的名稱和對應的類型（UTextBlock、EditableTextBox、UButton和UComboBoxString）。返回到 BP_VideoCallWiewVidget 編輯器中，給你拖動的UI元素設置相同的名稱。你可以通過點擊元素并在 "詳細信息 "面板中更改名稱來完成。嘗試編譯藍圖。如果你忘了添加什么東西，或者在你的UserWidget類中出現了widget名稱/類型不匹配的情況，你會出現一個錯誤。

C++在Unreal中如何為游戲增加實時音視頻互動

保存到文件夾中，例如 /Content/Widgets/BP_EnterChannelWidget.uasset。

創建 BP_VideoViewWidget Asset。

C++在Unreal中如何為游戲增加實時音視頻互動

設定圖片的錨點

C++在Unreal中如何為游戲增加實時音視頻互動

創建 BP_VideoCallViewWidget Asset

創建 BP VideoCallViewWidget Asset ，將父類設置為 UVideoCallViewWidget，并添加 BP VideoViewWidget 類型的 UI 元素MainVideoViewWidget 和ExtendedVideoViewWidget。同時添加 SizeBox 類型的 MainVideoSizeBox 和 AdditionalVideoSizeBox UI 元素。

C++在Unreal中如何為游戲增加實時音視頻互動

創建 BP_VideoCallWidget Asset

創建BPVideoCallWidget Asset，將父類設置為UVideoCallWidget，在 Palette UI 元素BPVideoCallViewWidget 中找到并添加名稱為VideoCallViewWidget，添加 EndCallButton、MuteLocalAudioButton 和 VideoModeButton 按鈕。

C++在Unreal中如何為游戲增加實時音視頻互動

創建 BP_VideoCallPlayerController blueprint asset

現在是創建 BPVideoCallPlayerPlayerController blueprint asset 的時候了，基于我們前面描述的 AVideoCallPlayerPlayerController 類，創建 BPVideoCallPlayerController 藍圖資產。

C++在Unreal中如何為游戲增加實時音視頻互動

創建一個AVideoCallPlayerPlayerController的bluepringt。右鍵點擊內容，按Add New按鈕，選擇Blueprint類，在窗口中選擇父類，在Pick parent類進入All classes部分，找到VideoCallPlayerController類。

現在將我們之前創建的小部件分配給PlayerController，如下圖所示。

C++在Unreal中如何為游戲增加實時音視頻互動

將其保存到文件夾，例如 /Content/Widgets/BP_VideoCallPlayerController.uasset。

創建 BP_AgoraVideoCallGameModeBase Asset

創建一個 AVideoCallPlayerController 的 Blueprint，右鍵點擊內容，按 Add New 按鈕，選擇 Blueprint 類，在 Pick parent class 窗口中選擇 Game Mode Base Class。這是所有游戲模式的父類。

修改 GameMode

現在你需要設置你的自定義 GameMode 類和玩家控制器。到世界設置中，設置指定的變量：

C++在Unreal中如何為游戲增加實時音視頻互動

指定項目的設置

進入 Edit->Project settings，打開 Maps & Modes。設定默認參數：

C++在Unreal中如何為游戲增加實時音視頻互動

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