In short''

1
In short..

• game
• blackjack
• mobile phone
• digital television
• interactivity between mobile user and digital
  televesion content

2
Overview of the game

• Like BlackJack you may know
• one dealer
• several players
• 21 limit
• each player plays against dealer
• usually the dealer ultimately wins

3
Overview of the mobile client

• like mobile game you may know..
• wireless
• graphical UI
• possibility to Win and Lose
• possibility to play whenever wanted
• private gameplay

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Overview of theMobile BlackJack

• MassiveMultiplayerMobileBlackjack
• number of participants is not limited
• location is not limited
• distributed gameplay and service
• highly interactive (vs. chat-games)
• integration with digital-tv
• potential business model

5
System
server
logic
renderer
television
dvb-c system
6
Mobile client principles

• Initiates the network connection
• Waits for command to play
• Independent interaction with human player
• Informs of the gamestate changes

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Mobile client technology

• JavaME
• midp 2.0 (mobile information device profile)
• cldc 1.1 (connected limited device configuration)
• Networking
• tcp/ip sockets (problematic)
• gprs/wlan
• Development platform
• Windows, GNU/Linux
• Eclipse, Nokia SDK
• Sun WTK2.2

java runtime for mobile devices
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Server principles

• Nonmovable component
• administrates user accounts
• maintains all the connections to clients
• operates as a gateway between other components
• different services to game and clients
• fast login and messaging, lazy closer
• passive operating strategy - waits for the
  messages and responds

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Server technology

• Sun Java 1.4.1-07
• multithreaded one thread for each client
• tcp/ip sockets
• byte streams in/out
• could have been objects
• simple

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Logic principles 1/2

• Heartbeat of the game
• controls the game, server and mobile clients with
  spesific messages and timing
• ticks forever
• doesnt care if there are any players
• replaceable eg. human behaviour

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Logic principles 2/2

• Independent actor, knows nobody
• communicates only with communication channel

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Renderer principles

• Deeply independent no message sending
• receives messages and acts on them
• draws in a doublebuffered way into the main
  window
• constructs a ppm-image of the buffered image and
  writes it to a pipe 25 frames/sec

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Renderer
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Renderer tehnics

• Cards are made with a CardFactory which can be
  used in many card games.
• can make any card image
• animations are done with image arrays and
  animation queues
• uses direct reference to the image buffer that is
  representing the game
• makes use of application named ffmpeg to compress
  the game image to mpeg2

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Messaging

• Effective way to separate components
• Good way to make life more complicated if it is
  not well planned

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example

• //from client to server
• public static final String LOGIN"//LOGIN"
• public static final String INFO"//INFO"
• public static final String STOPPED"//stoppedPlay
  ing"
• //from server to client
• public static final String LOGIN_RESULT"//LOGIN_
  "
• public static final String LOGIN_FAILED"//LOGIN_
  FAILED"
• public static final String UPDATE"//UPDATE"
• public static final String CREDITS"//CREDITS"

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example

• //announcements from dealer to server
• / To server ask clients to send their
  cerdits/
• public static final String GETCREDITS"//GET_CRED
  ITS"
• / Dealer wants to know if anyone is still
  playing /
• public static final String SOMEBODYPLAYING"//SOM
  EBODYPLAYING"
• / Dealer wants server to pick some number of
  clients that are updating
• their game to the game screen side view/
• public static final String CLIENTUPDATES"//makeC
  lientUpdates"
• //from server to dealer
• / /
• public static final String STILLPLAYING"//someBo
  dyStillPlaying"

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examples, local messaging

• //announcements directly to game from dealer.
• / From Deal to Game Start waiting for clients
  to choose weights. /
• public static final String WAITFORWEIGHTS"/waitf
  orweights"
• / From Deal to Game Dealer has finished
  taking cards. /
• public static final String DEALERFINISHED"/deale
  rfinished"
• / From Deal to Game Change on dealers cards.
  /
• public static final String DEALERSCARDSCHENGED
  "/dealerscardschanged"
• / Clears the side on the game screen/
• public static final String CLEAR_SIDE"//SIDE_CLE
  AR"
• / Expresses that dealer has some message to
  game./
• public static final String TO_GAME"//TO_GAME"
• / tells game that dealers card has been
  taken./
• public static final String DEALERCARD"dealerCard
  "

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Problems?

• Unthinkable problems with getting responce from
  any server when using sockets in midlet
• typical problem with all input streams in Nokia
  java implementation
• Effective way to get the game image to be
  processed
• several potential solutions one working

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QUESTIONS??
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Demonstration