Department of Applied Informatics and Multimedia, Technological Educational Institute of Crete Heraklion, Crete, Greece

1kapekost@epp.teicrete.gr, 2mtp1@edu.teicrete.gr, 3tp3289@edu.teicrete.gr, 4epp2355@edu.teicrete.gr, 5epp2211@edu.teicrete.gr, 6ip@epp.teicrete.gr

Abstract— Within the context of a 3D interactive strategy game, the EViE platform allows participants to unlock game features using their knowledge and skills in various thematic areas such as physics, mathematics, etc. By answering questions organized by Educational Objective in stratified levels of difficulty, users gather points which grant them access to desired world elements. Richer world components become increasingly more difficult to access, so that a players’ individual (or cumulative if in a group) knowledge, ability and / or dexterity is directly reflected by the level of complication of their virtual world. In the present article we report on the communication architecture of the platform and focus on framework components that allow group activities such as cooperation (within the group to facilitate e.g., collaboration on more difficult problems), (inter-group) competition as well as practice and skill honing activities (in single or in multi-player mode).

Keywords Virtual Worlds, EViE-m, Xj3D libraries

A. The Question Manager module

B. The Team-Selection Module

C. Intra-communication Module

D. Text Communication Module and Information Module

WelcomeMessage(groups)

WelcomeMessage (SelectionMessage)

WelcomeMessage (groupList)

Add group to the list of available groups

Create list of players

in Group

YESNO

Network Manager Select group

WelcomeMessage (remove)

List of players

DisconnectConnect

Synchronize list in all peers

MessageCreation (data)

MessageRotation (data)

MessageTranslation (data)

GamePlay

Synchronize world in all peers

E. Construction Module

run.bat Java - Xj3D Browser

Java - invoke X3D world and JFrame to

render graphics

X3D world -trigger Java core

Java - mapping X3D

current status -w_status.xml

Xj3DBrowser

No package so class can be

invoked from X3D script

JFrame - 3D Rendering

Customized to start with the

predefined X3D file

BuildingPanelSC

Initializing

Attach listeners to X3D models

Network button

message pop-ups

Properties.xml validation

Set the points

Communication

CommunicationWindow

Log chat xml

Multicast System ChatMessage

Change nickname

Networklayer.MulticastNet

Manage incoming and outgoing

messages

235.255.0.1

224.0.255.1

224.0.0.0

235.0.0.1

Port 5000

Networklayer.impl. InputListener

Messages and LEvel Types

Level 1: unlock

Level 11: forwarding

Level 2: structure received

Xj3dp2p. WorldManager

XJ3D Browser Instance

Merge X3D models and Write status

Check for model ID

Save/Load world state Check and

update leveladdNewBuilding, add car animation

model

Xj3dp2p.buildings. Building

Get the requested x3d file

Lock a building - if built from other

Lan user

Alter x3d file

Append needed listeners to assign

events

Cooperation with BuildingNurse

Xj3dp2p.housemanager. Housemanager

Calculate points

Check prerequisites

Validate the prerequisites

Xj3dp2p.msg

Package identical “Messages”

classes

MessageCreation

MessageRotation

Message Translation

Message Welcome

NetworkManagerListen & process

messages

Virtual Realities

Seventh IEEE

International Symposium On Distributed Simulation and Real-Time Applications, pp.

Xj3dp2p.questions

Read external xml files

Check results

Update game points

Xj3dp2p.xml XMLHelper.java

Manage all the XML parsing and saving

procedures