UE4官网针对热更新有较为详细的步骤，但是其中漏掉的几个问题导致实现不了效果。
总的来说可以分为四大步。
第一步：自己的项目设置好插件ChunkDownloader
1.新建第三人称c 项目工程，设置分块打包
2.勾选插件ChunkDownloader
3.修改项目的 Build.cs 文件
PrivateDependencyModuleNames.AddRange(
new string[]
{
"ChunkDownloader"
}
4.保存后重新生成项目文件。操作：右键点击你的 .uproject 文件，然后点击 生成项目文件（Generate Project Files）。
第二步：资源分块，然后打包。为了测试方便，新建三个map，分别放在不同的文件夹。我的是Test，Test2，Test3.
- 添加资源分块标签。
标签设置如图：红框内需必备
属性解释：
依次对自己的测试资源添加标签。
2.打包默认设置即可。这样你可以在打出的包里看到分好的pak文件。红框ID与你的标签ID对应。
第三步：构建资源清单与托管本地测试服务器
1.构建资源清单。这里注意，英文字符下 TAB建进行属性空格。
我的清单如下：
资源文件夹结构，其中Windows文件夹中放的是分块后的pak文件
稍作解释：
第1行是需要下载更新的pak数目
第2行理解为资源和清单所在的文件夹
后面的几行就是pak资源相关的。共5个属性。资源名字，资源大小（右键资源看其属性字节数），版本号，ChunkID，资源所在位置。
2.文件托管到本地测试服务器
如何创建本地测试服务器这里不啰嗦，可以参考ue4官网。
但是这里要注意：新建文件夹PatchingDemoCDN，除了上传我们前面准备好的资源和清单即PatchingDemoKey文件夹。我们还需要在PatchingDemoCDN文件夹中新建表单
这个表单中我们要写上$BUILD_ID对应的也就是资源和清单所在的文件夹PatchingDemoKey
最后我们还需要在项目的配置表DefaultGame.ini中添加用来下载资源的网站地址。这里我们是用本地服务器测试的。
[/Script/Plugins.ChunkDownloader PatchingDemoLive]
CdnBaseUrls=127.0.0.1/PatchingDemoCDN
第三步：编辑代码和逻辑。（开始不必扩展，实现基本功能即可）
1.GameInstance不仅具有可以绑定的相应初始化和关闭函数，而且还可以在游戏运行时持续访问ChunkDownloader。
所以使用 GameInstance 作为基类创建 新C 类。将其命名为 PatchingDemoGameInstance。
最后代码为：
.h
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "Engine/GameInstance.h"
#include "PatchingDemoGameInstance.generated.h"
/**
*
*/
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FPatchCompleteDelegate, bool, Succeeded);
UCLASS()
class UPatchingDemoGameInstance : public UGameInstance
{
GENERATED_BODY()
public:
/** Overrides */
virtual void Init() override;
virtual void Shutdown() override;
/** Delegates */
/** Fired when the patching process succeeds or fails */
UPROPERTY(BlueprintAssignable, Category = "Patching")
FPatchCompleteDelegate OnPatchComplete;
/** Starts the game patching process. Returns false if the patching manifest is not up to date. */
UFUNCTION(BlueprintCallable, Category = "Patching")
bool PatchGame();
UFUNCTION(BlueprintPure, Category = "Patching|Stats")
void GetLoadingProgress(int32& FilesDownloaded, int32& TotalFilesToDownload, float& DownloadPercent, int32& ChunksMounted, int32& TotalChunksToMount, float& MountPercent) const;
protected:
//Tracks Whether or not our local manifest file is up to date with the one hosted on our website
bool bIsDownloadManifestUpToDate;
void OnManifestUpdateComplete(bool bSuccess);
/** List of Chunk IDs to try and download */
UPROPERTY(EditDefaultsOnly, Category = "Patching")
TArray<int32> ChunkDownloadList;
/** Called when the chunk download process finishes */
void OnDownloadComplete(bool bSuccess);
/** Called whenever ChunkDownloader's loading mode is finished*/
void OnLoadingModeComplete(bool bSuccess);
/** Called when ChunkDownloader finishes mounting chunks */
void OnMountComplete(bool bSuccess);
};
.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "PatchingDemoGameInstance.h"
#include "ChunkDownloader.h"
#include "Misc/CoreDelegates.h"
#include "AssetRegistryModule.h"
void UPatchingDemoGameInstance::Init()
{
Super::Init();
const FString DeploymentName = "PatchingDemoLive";
const FString ContentBuildId = "PatchingDemoKey";
// initialize the chunk downloader
TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetOrCreate();
// TODO 安卓下载方式
// Downloader->Initialize("Android", 8);
Downloader->Initialize("Windows", 8);
// load the cached build ID
Downloader->LoadCachedBuild(DeploymentName);
// update the build manifest file
TFunction<void(bool bSuccess)> UpdateCompleteCallback = [&](bool bSuccess){bIsDownloadManifestUpToDate = true;};
Downloader->UpdateBuild(DeploymentName, ContentBuildId, UpdateCompleteCallback);
}
void UPatchingDemoGameInstance::Shutdown()
{
Super::Shutdown();
// Shut down ChunkDownloader
FChunkDownloader::Shutdown();
}
void UPatchingDemoGameInstance::OnManifestUpdateComplete(bool bSuccess)
{
bIsDownloadManifestUpToDate = bSuccess;
}
void UPatchingDemoGameInstance::GetLoadingProgress(int32& BytesDownloaded, int32& TotalBytesToDownload, float& DownloadPercent, int32& ChunksMounted, int32& TotalChunksToMount, float& MountPercent) const
{
//Get a reference to ChunkDownloader
TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetChecked();
//Get the loading stats struct
FChunkDownloader::FStats LoadingStats = Downloader->GetLoadingStats();
//Get the bytes downloaded and bytes to download
BytesDownloaded = LoadingStats.BytesDownloaded;
TotalBytesToDownload = LoadingStats.TotalBytesToDownload;
//Get the number of chunks mounted and chunks to download
ChunksMounted = LoadingStats.ChunksMounted;
TotalChunksToMount = LoadingStats.TotalChunksToMount;
//Calculate the download and mount percent using the above stats
DownloadPercent = ((float)BytesDownloaded / (float)TotalBytesToDownload)*100.0f;
MountPercent = ((float)ChunksMounted / (float)TotalChunksToMount)*100.0f;
}
void UPatchingDemoGameInstance::OnLoadingModeComplete(bool bSuccess)
{
OnDownloadComplete(bSuccess);
}
void UPatchingDemoGameInstance::OnMountComplete(bool bSuccess)
{
OnPatchComplete.Broadcast(bSuccess);
}
bool UPatchingDemoGameInstance::PatchGame()
{
// make sure the download manifest is up to date
if (bIsDownloadManifestUpToDate)
{
// get the chunk downloader
TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetChecked();
// report current chunk status
for (int32 ChunkID : ChunkDownloadList)
{
int32 ChunkStatus = static_cast<int32>(Downloader->GetChunkStatus(ChunkID));
UE_LOG(LogTemp, Display, TEXT("Chunk %i status: %i"), ChunkID, ChunkStatus);
}
TFunction<void(bool bSuccess)> DownloadCompleteCallback = [&](bool bSuccess) {OnDownloadComplete(bSuccess); };
Downloader->DownloadChunks(ChunkDownloadList, DownloadCompleteCallback, 1);
// start loading mode
TFunction<void(bool bSuccess)> LoadingModeCompleteCallback = [&](bool bSuccess) {OnLoadingModeComplete(bSuccess); };
Downloader->BeginLoadingMode(LoadingModeCompleteCallback);
return true;
}
// we couldn't contact the server to validate our manifest, so we can't patch
UE_LOG(LogTemp, Display, TEXT("Manifest Update Failed. Can't patch the game"));
return false;
}
void UPatchingDemoGameInstance::OnDownloadComplete(bool bSuccess)
{
if (bSuccess)
{
UE_LOG(LogTemp, Display, TEXT("Download complete"));
// get the chunk downloader
TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetChecked();
FJsonSerializableArrayInt DownloadedChunks;
for (int32 ChunkID : ChunkDownloadList)
{
DownloadedChunks.Add(ChunkID);
}
//Mount the chunks
TFunction<void(bool bSuccess)> MountCompleteCallback = [&](bool bSuccess) {OnMountComplete(bSuccess); };
Downloader->MountChunks(DownloadedChunks, MountCompleteCallback);
OnPatchComplete.Broadcast(true);
}
else
{
UE_LOG(LogTemp, Display, TEXT("Load process failed"));
// call the delegate
OnPatchComplete.Broadcast(false);
}
}
2.使用 PatchingDemoGameInstance 作为基类创建 新蓝图，命名为 CDGameInstance
3.打开CDGameInstance，添加chunk列表
4.创建名为 PatchingGameMode 的新游戏模式 蓝图
5.项目做如下设置。
6.第三人称游戏map设置gamemode为PatchingGameMode
7.打开PatchingGameMode，添加如下蓝图逻辑。
beginPlay后添加：patchGame返回值为true则进入tick即开始下载资源。否则根据资源数进行进一步检测。
tick后添加：大概意思就是资源下载并且装载完打开Test3地图。
到此代码，逻辑都写好了。
第四步：打包测试
1.直接打包。
结果是包文件夹里的Content中的paks文件夹有四个pak文件。删掉ID为1001-1003的pak。
2.运行.exe
结果如下：
下载中
下载完成，3秒后进入Test3地图。
下载的文件：
