基于视点相关透视纹理的矢量数据在三维地形上的叠加绘制

Rendering Vector Data over 3D Terrain with View-Dependent Perspective Texture-Mapping

为了精确、高效地将传统二维矢量数据叠加到三维多分辨率地形上,提出一种基于视点相关透视纹理的叠加绘制算法.首先通过场景视点得到能充分逼近当前地形可视范围的透视投影,然后用该透视投影实时地将二维矢量数据绘制在与地形绑定的纹理上,同时在GPU中并行计算出纹理坐标.与传统的基于纹理的绘制方法相比,视点相关的透视投影能够提高纹理的像素利用率,从而减轻传统方法所产生的走样问题,提高矢量数据的绘制质量;且该算法不受地形几何数据的约束,能够与目前大多数多分辨率地形模型以及影像金字塔很好地结合在一起使用.

This paper presents a texture-based algorithm for vector data display that is able to precisely and efficiently overlay traditional 2D vector data on a 3D multi-resolution terrain model.By the algorithm,depending on the view to the scene first,a perspective projection is created,to match the currently visible range of the terrain.Then the projection is used to generate the texture on-the-fly with the texture coordinates calculated on GPU.The quality superior to standard texture mapping can be achieved by using the view-dependent perspective projection,for improving the availability ratio of texture pixels.In addition,since the algorithm is independent of the underlying terrain geometry,it is suited to work with terrain LOD algorithms and image pyramid.