Integrating a Cloud Service

Joe Graf@EpicCog

Overview

• Example from our games

• Support in UE4 to achieve that

Cloud Based Events

• Timed gameplay changing events– The limited time draws players in

• Used to make your game “evergreen”– Retains players longer– Adds to the fun

Gears of War

• Gears of War 2– Used to make gameplay balancing changes– Primarily, to create custom Horde events

• Gears of War 3– Added the ability to change standard game modes

• Restrict weapons or change which ones were present

– Allowed for custom playlists for matchmaking

Infinity Blade

• Infinity Blade 2– Used to support social challenges, ClashMobs– Custom INI files detailing the challenges

• Infinity Blade 3– Added the ability to patch configuration settings– Used to run special helmet events– IAP sales– The treasure chest in the Hideout

What’s Needed

• Cloud Service to deliver files

• Game support to download files

• Game support to merge files into game

Cloud Service

• System (game) cloud storage– Upload of files with start/stop times– Listing of files with full meta data– Serving of files to game client

Game Downloader

• Reads list of files from the Cloud Service– Verifies signatures to detect out of date files– Catches tampered with files too

• Downloads any missing files– Caches files to device with per device

encryption– Optimization to reduce server bandwidth costs

Game Merging

• Gets the list of event files

• For each file, determines how to merge– INI & loc files get merged into the config

cache– Content files replace/add to existing

Caveats

• Game must design for this–Must make sure that game is data

driven via INI or DataTable objects– Takes planning from the beginning

• Not everything can be updated– E.g. very early engine config values

Game to Service Interaction

Cloud Service(s)

Cloud Service(s)

IHttpRequest

IHttpResponse

Class Overview

• FHttpModule

• IHttpRequest

• IHttpResponse

FHttpModule

• Module for generic HTTP management

• Performs ticking

• Handles lifetime management

IHttpRequest

• Abstract interface to a platform specific request object

• Contains– URL– Verb (GET, PUT, POST, DELETE)– Headers– Payload

• Asynchronous submission to end point

IHttpResponse

• Abstract interface to a platform specific response object

• Created upon request completion

• Contains any headers & payload data

TJsonReader/TJsonWriter

• Base template classes for parsing/creating JSON payloads

• Generally not used directly

OnlineJsonSerializer

• Macro based serialization for native types without reflection

• Facebook account serialization:

BEGIN_ONLINE_JSON_SERIALIZERONLINE_JSON_SERIALIZE("id", UserId);ONLINE_JSON_SERIALIZE("username", UserName);ONLINE_JSON_SERIALIZE("name", RealName);ONLINE_JSON_SERIALIZE("gender", Gender);ONLINE_JSON_SERIALIZE("locale", Locale);

END_ONLINE_JSON_SERIALIZER

FJsonObjectxConverter

• Used to serialize JSON to/from a UObject

• Uses UObject reflection system

• Easiest to use

Questions?

Documentation, Tutorials, and Help at:• AnswerHub:• Engine Documentation:• Official Forums: • Community Wiki:• YouTube Videos:• Community IRC:

Unreal Engine 4 Roadmap• lmgtfy.com/?q=Unreal+engine+Trello+

http://answers.unrealengine.comhttp://docs.unrealengine.comhttp://forums.unrealengine.comhttp://wiki.unrealengine.comhttp://www.youtube.com/user/UnrealDevelopmentKit#unrealengine on FreeNode