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– Verifies signatures to detect out of date files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
IHttpRequest
IHttpResponse
Cloud
Service(s)
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
–
–
–
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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_SERIALIZER
ONLINE_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:
http://answers.unrealengine.com
• Engine Documentation:http://docs.unrealengine.com
• Official Forums:
http://forums.unrealengine.com
• Community Wiki:
http://wiki.unrealengine.com
• YouTube Videos:
http://www.youtube.com/user/UnrealDevelopmentKit
• Community IRC:
#unrealengine on FreeNode
Unreal Engine 4 Roadmap
•
lmgtfy.com/?q=Unreal+engine+Trello+