分布式虚拟环境综述

ISSN1000-9825JournalofSoftware2000,11(4):461467潘志庚　姜晓红　张明敏　石教英(CAD&CG310027)E-mail:[e-mail]在分布式虚拟环境中,位于不同物理位置的多个用户或多个虚拟环境通过网络相互联结,进行信息共享和交互.该文结合作者的研究工作,从分布式虚拟环境的产生、需求和特征、模型和结构以及系统关键技术这几个方面对分布式虚拟环境的研究情况进行综述,讨论了存在的问题和进一步的发展方向.虚拟现实,分布式虚拟环境,可扩展性,网络通信,虚拟现实建模语言.TP393,.,,,(virtualreality,VR,(virtualenvironment,VE)[1]..,,,,.,.,Internet,,,.(distributedvirtualenvironment,DVE),VE.,,.,,,,.DVE80.,DVE[2].,DVE.DVE,SIMNET[3].,,DVE.,SIMNETDIS,DVE(IEEE1978).DVE.GaryTarolli1984SGIFlight.DoomVR.VRMacintoshMarathonAppletalkBolo.90,VR,DVE,.DVE5[2]:(1);(2);(3),;(4);(5).(No.69823003).,1965,,,,,.,,1966,,,.,,1968,,,.,1937,,,,.:,310027,CAD&CG1999-04-12,1999-11-23DVE4:.DVEVR,:VR,1.Table1RequirementsofDVEsystems1DVERequirementsofVRRequirementsofdistributedsystemsRenderinginvariousforms(graphics,audio,text)Namingservice!Lowlatency,highupdatingrate∀Service-Requestmatching#Capabilitytoprocessdifferentinputdevices∃Resourcefindingandlocation%Collisiondetection&DistributedstorageofdataNavigationandviewpointcontrollingDynamicloadbalancing!Constructionofvirtualworld∀Securitymanagement#Managementofscenedatabase∃Multicast%Complexbehaviormodeling&Supportforcontinuousmedia∋VR,,(),!,∀,#-,∃,%,&,,,!,∀,#,∃,%,&,∋.11.1DVEDVE,DVEDVE,DVE.90,DVEDVE.NPSNET[4]DIVE[5]BrickNet/NetEffet[6]AlbertMR[7]NottinghamAVIARY[8]DIVER[9]DivisiondVS[10].VR90,[1114].DVE,DVENET[15,16];DVEYHYRP[17];,DVE[18].DVE,DVE,.Arai[19]DVE,.Maxield[20]DVE,.DVE[21].DVE,[4,15].,DVE[22].,Internet,InternetDVE,[2224].1.2dVS[10],Division.1999,CADProEngineerPTCDivision,CAD/VRDivision2000i.CAVEImmersiveDesktop,.MR[7]AlbertaVR..MR.SGIDECC.DIVE[5]1993,.NPSNET[4](NPS),IEEE1278(DIS)IP3D,462JournalofSoftware　软件学报　2000,11(4)Internet.AVIARY[8]VR,.AVIARYNottingham(AIG),.DVENET[15]DVE,DVE,DVENET.2.Table2CompareofdistributionfeaturesintypicalDVEsystems2DVESystemsdVSMRDIVENPSNETAVIARYDVENETSharingmodelSharedDBSharedDS!SharedDBDIS∀Objectoriented#DISReplication∃Partial%2copies&WholeWholeWholeWholeCommunicationschemeC/SMaster/SlaveandPeer-to-PeerPeer-to-PeerPeer-to-PeerPeer-to-Peerandmessagepassing!C/Sandbroadcast!Distributedcomputation#Nosupport∃support%NosupportNosupportSupportSupportParallelgranularity&Coarse∋CoarseCoarseCoarseFine(CoarseParallelunit)Process)ProcessProcessPlayerObject)!ObjectLoadbalancing)∀NosupportNosupportNosupportNosupportSupportN/ANetworkenvironment)#Hetero-geneous)∃Hetero-geneousHetero-geneousHetero-geneousHetero-geneousHetero-geneous,,,!,∀,#,∃,%,&2,,,!Peer-to-peer,∀C/S,#,∃,%,&,∋,(,),),)!,)∀,)#,)∃.2DVE2.1DVE.,,,.,,,.,,,.,,,(robustness).,,,,.,,.:,..2.2DVE2.2.1DSDS(decoupledsimulationmodel,)DVE.,,.DS,4,.,463潘志庚等:分布式虚拟环境综述....VR,,,.AlbertMR.1.2.2.2MPSCMPSC(modifier-presenter-sensor-controller).4(2),.4.VR,,VR.,..,..(a),..(b).(c).3DVEDVE,,DVE,.3.1DVE(1)DVE:(a)[25];(b);(c);(d).DR(deadreckoning);(),,.Plug-inJava/VRML[26],,[27].(2)--VR,..,.DVE,-,-,[28].DVE..CSCW,DVECSCW,.464JournalofSoftware　软件学报　2000,11(4)(3)DVE,DVE.DVE,.DVE,VE.DVE,,DVE...,DVE,DVE.(virtualrealitytransportprotocols,VRTP).(4)VE,(,),,.DVE.,.VR(),DVE,.[14][10][12],.3.23.2.1.DVE.,..3.2.2,..,,NPSNET-IVMboneMulticast,DeadReckoning[5].,NPSNET-IV,().,,.3.2.3DVE,,,.,-,-.3.2.4,DVE,.,,,,.3.2.5,.[2].4DVE,.DVE,,.DVE,:().DVE:(1).,465潘志庚等:分布式虚拟环境综述(cooperativevirtualenvironment,CVE),.(2)InternetATM.Internet,,(),.,ATM.ATMCAVEDVE.(3).DVE,VR,..(4)DVE.,,.(5)DVE,,,.(6)DVE.,,,,,,agent..,,.1StytzM.Distributedvirtualenvironments.IEEEComputerGraphicsandApplication,1996,16(3):19312SnowdonS,GreenhalghCetal.AreviewofdistributedarchitecturefornetworkedVR.VR:Research,DevelopmentandApplication,1996,2(1):1551753LockeJ.AnintroductiontotheInternetnetworkingenvironmentandSIMNET/DIS.TechnicalReport,NavalPostgraduateSchool,19934MacedoniaMR,ZydaMJ.NPSNET:anetworksoftwarearchitectureforlargescaleVE.Presence,1994,3(4):2652875GagsandO.Interactivemulti-userVEsintheDVEsystem.IEEEMultimedia,1996,3(1):30396SinghG,SerraL.BrickNet:asoftwaretoolkitfornetworkbasedvirtualworlds.Presence,1994,3(1):19347GreenM,ShawC.Minimalrealitytoolkit.TechnicalReport,UniversityofAlberta,19938SnowdonDN,WestAJ.AVIARY:designissuesforfuturelarge-scaleVE.Presence,1994,3(4):2883089GossweilerR,ChrisLong,ShuichiKogaetal.DIVER:adistributedvirtualenvironmentresearchplatform.In:VanDamed.ProceedingsoftheIEEESymposiumonResearchFrontiersinVR.LasAlamitos,CA:IEEEComputerSocietyPress,1993.101510DivisionLtd.dVSTechnicalOverview.1993,(3):18719412CaiYong,LiuXue-hui,WuEn-hua.AvirtualrealitysystembasedonIBR.JournalofSoftware,1997,8(10):721728(,,..,1997,8(10):721728)13WangZhao-qi,ZhaoQin-ping,WangCheng-wei.ObjectorientedcollisiondetectionanditsapplicationinDVE.ChineseJournalofComputers,1998,21(11):990994(,,..,1998,21(11):990994)14LiJie,TangZe-sheng.Real-Timemulti-resolutionrenderingof3Dcomplexmodels.ChineseJournalofComputers,1998,21(6):481491(,..,1998,21(6):481491)15ZhaoQin-ping,ShenXu-kun,XiaChun-heetal.DVENET:adistr