一种基于位置关系判定的GPU三维几何图元拾取方法

A 3D Geometric Primitive Picking Method on GPU by Positional Relation Judgment

针对交互式图形应用对拾取在效率、适用范围和拾取信息方面的需求,提出一种新的基于GPU的三维几何图元拾取方法。在进行拾取绘制时关闭光栅化,将鼠标位置信息和图元顶点坐标变换到规范化设备坐标系,通过在几何处理器中判断投影后的二维图元与鼠标或选择框的位置关系进行命中判定,并利用变换反馈将拾取信息返回应用程序。在提出方法的基础上,介绍了单体拾取和块拾取的Open GL实现。实验表明,该方法的单体拾取效率较基于GPU的射线相交法有约10%的提升,同时能支持高效块拾取。

3D geometry primitive picking is a key technique for 3D interactive graphics applications which is required to be highly efficient,widely applicable and able to obtain rich information.In order to satisfy these requirements,a novel GPU-based 3D geometric primitive picking method is proposed.The drawing for picking is conducted as follows：rasterization is first turned off,then the mouse position and coordinates of primitive vertexes are transformed to the normalized equipment coordinate system,and hit test is made on the geometry processor by judging the positional relation between the 2D projected primitive and the mouse position or selection box,at last picking results are returned to the application by utilization of transform feedback.Based on this method,the OpenGL implementation of single-object picking and block picking are both discussed.Experiments show that the proposed method is about 10％ faster than GPU-based ray intersection method in terms of single-object picking,and it can support efficient block picking.