Research On Parallel Rendering Algorithm About Large-scale Scene Of3DCM

With the data amount of the3-dimensional model increases and the rapid development ofcomputer graphics hardware in recent years, three dimensional city mode (3DCM) scenereal-time parallel rendering algorithms are being researched, which is a new field of study inthe field of computer graphics and virtual reality. Because of Development of remote sensingtechnology, satellite technology, three dimensional terrain geometry and texture data is moreand more large, some new methods are was looking forward to be given, which include amore natural and realistic way to look a wide range of terrain, an effective method fororganizing storage data, rational and efficient dynamic scheduling algorithm. These newmethods are the key technology for real-time displaying and interacting about large-scalescenes in vivid.1.The ray casting algorithm of geometry drawing is researched. Combination ofmulti-core processor clusters, a parallel ray-casting volume rendering algorithm is givenbased on multi-level a parallel programming model, which can be applied to3DCM scenedraws.2.According to the scale3DCM terrain data characteristics, with a top-down quad-treeterrain simplification method, a multithreaded algorithm in which LOD block tiered is givenbased on multi-core parallel technology. By blocking policy the scene range are divided intoequal quadrants, in which the node split as distance, the nodes closed to view point will splitsmall, in order to the terrain area displays more fine, and the nodes far from view point willsplit large, in order to the terrain area displays more rough. This way can reduce the volumeof data and the complexity of algorithms, and make calculation tasks average assigned to fourthreads independently.3.In LOD model simplification algorithm, by limiting to generate the strips of triangles,error accumulation in combination to edge collapse and using vertex importance, a maintainthe Visual features simplification algorithm of LOD model is given. The experimental resultsshow that the algorithm can well keep the important geometric characteristics of model, as anautomatic mesh simplification algorithm, which can simplify3DCM model operation.4.In response to distribution characteristics of geometric entities about parallel renderingtasks of3DCM scene, this thesis use dynamic load-balancing algorithm to implementdividing tasks and assignments about drawing3DCM scene. In3DCM scene drawing tasks set which are executed in the order, according to a possible parallel between its child tasks,the3DCM scene drawing tasks set is divided into a number of tasks that can be performedconcurrently subset in which a processor is assigned, so their data can keep synchronousprocessing, load balancing between processors as possible.