基于位移映射的道路生成与绘制方法

Road Generating and Rendering Method Based on Displacement Mapping

以矢量形式表达的道路信息在地理信息系统中占有重要地位。通过位移映射方法解决了三维地形上道路的生成与绘制问题。首先,在考虑道路几何约束的情况下,根据道路平面图以及相应的DEM数据生成参考曲面;然后,通过对参考曲面的一次离屏渲染,利用深度图方法生成DEM位移图和纹理掩模图;在地形绘制中同时使用位移映射和纹理映射,实现道路几何信息以及细节信息的实时嵌入。实验表明,这种方法在小尺度显示中以较低的代价增强了道路仿真绘制的真实感。

Road information which is represented in vector form plays an important role in geographical information systems.A displacement mapping based approach was introduced to realize the generating and rendering of roads on three-dimensional terrain.First,taking the geometric constrains of roads into account,a reference surface was generated in accordance with the roads plan and the relevant DEM data;second,by off-screen rendering for the reference surface,DEM displacement map and texture mask were generated using depth map method.Displacement mapping and texture mapping were used in rendering to achieve a real-time embedding of the geometric and detail information of the road.Results show： the approach enhances the appearance of road in small-scale rendering at a very low cost.