简介:Inthepreprocessingphase,theglobalterrainmodelispartitionedintoblockswiththeirfeaturepointsbeingpickedouttogenerateTINmodelforeachterrainblock,thenthemulti-resolutionmodelsofterrainorganizedintheformofquad-treeiscreatedbottom-up.Cracksbetweenterrainblocksareavoidedbyinsertingverticestoformcommonboundaries.Atrun-time,aview-dependentLODalgorithmisusedtocontroltheloadingandunloadingoftheproperblocksbyanadditionalsynchronousthread.ToeliminatetheartifactscreatedbyLODtransitions,geomorphingisusedinreal-time.TheserenderingstrategiesincreasethethroughputofGPUandavoidimbalanceofloadamongCPU,GPUandDiskI/O.Experimentalresultsshowthatthesystemcanperformvisuallysmoothrenderingoflarge-scaleterrainsceneswithfinequalityatanaveragerateof80fps.
简介:Accordingtothetopographyofmountains,thediscretedatapointsfrommapofthewholeregionarefirstsubdividedintosubregionswiththepointstakenfromthefeaturelinesofridge,valleyandscarpbeinginsertedintothemappointset,andusingthefeaturelinesastheboundariesofsubregionstobuildconstrainedDelaunayTIN.Suchanapproachhastheadvantagesofensuringhighaccuracyandfastspeedoflinelayout.