Multi-resolution Geometry Image Real-time Rending Research

With the wide application of virtual reality technology, many other areas such as theprotection of cultural relics, film game, and so on, put forward high request on thereal-time rendering of3D model. The rapid development of laser scanner makes the modeldata is more and more big, and the topological structure of network is more and morecomplex. Therefore, how to take effective measures to realize the3D model’s fastreal-time rending is an important and challenging work, and has profound significance.Firstly, using the geometry image technology to realize the present of3D model, andapply the proven technologies of single-chart cut, spherical parameterization, andresampling to get the geometry image of3D model. Using geometry image technology canpresent the3D model as a form of completely regular2D image, and can reduce theamount of data needs store.Secondly, based on the analysis of the extensive error metric methods, we putforward a calculation method of the node error based on distance difference and normalvector’s change, and make the comprehensive consideration of the influence of distancedifference and normal vector’s change on node error. We also introduce the concept ofhierarchy bounding sphere and the idea of error metric based on screen space, and presenta error metric suitable for view-dependent geometry image.Thirdly, we introduce enum quadtree idea into the traditional quadtree design, use asingle enum quadtree node as independent render unit, greatly reduce the schedulingnumber of drawing function. In data preprocessing stage, we structure basic rendering unitof enum quadtree, and eliminate internal crack of basic render unit, as a result, reduce thecrack quantity during real-time rendering effectively.Fourthly, we propose using the tangent function to control points shift, and repairbasic rendering unit’s external cracks on GPU’s Vertex Shader. The crack process methodis completely realized on GPU, and can process multi-span cracks, by adjusting theparameters, we can make the grid distribution more uniform and generate few narrowtriangle.Finally, we design a multi-resolution geometry image real-time rendering system to validate the effectiveness of the methods proposed. Experimental results show that thesystem can realize fast real-time rending of multi-resolution image geometry, and canobtain high frame rate and better rending effect.