现有的虚拟地球中的海面可视化方法主要采用投影网格的方式组织海面格网，这种特殊的网格组织方式，导致其在反映不同海域差异性特征时存在缺陷。基于全球离散格网的海面可视化方法由于能够与虚拟地球离散的空间剖分相匹配，有效弥补了投影网格法的缺陷，因此更符合虚拟地球海面仿真应用的需要。然而现有的离散格网法存在绘制效率差、场景加载慢、需要修补格网缝隙等问题，限制了其应用发展。对此，本文在现有离散格网法基础上进行优化：首先，在数据结构上对传统等经纬度离散格网进行扩展，设计了一种面向GPU绘制的多尺度海面网格模型来组织管理海面格网；其次，为了实现风场驱动下的海浪动态绘制，在多尺度海面网格模型的基础上提出了一种支持实时风场更新的海浪动态绘制方法；同时，考虑到格网缝隙修补对系统效率的影响，本文针对海面格网特点并结合GPU技术提出了一种高效的海面格网缝隙修补方法。最后通过对比试验验证了本文方法的可行性和有效性。试验结果表明，本文方法绘制效率稳定，加载速度快，且能弥补现有方法在功能上的缺失，因此应用范围更加广泛。
The existing visualization method in the virtual globe mainly uses the projection grid to organize the ocean grid. This special grid organization has the defects in reflecting the difference characteristics of different ocean areas. The method of global ocean visualization based on global discrete grid can make up the defect of the projection grid method by matching with the discrete space of the virtual globe, so it is more suitable for the virtual ocean surface simulation application.But the available global discrete grids method has many problems which limiting its application such as the low efficiency of rendering and loading, the need of repairing grid crevices. To this point, we propose an optimization for the global discrete grids method. At first, a GPU-oriented multi-scale grid model of ocean surface which develops on the foundation of global discrete grids was designed to organize and manage the ocean surface grids. Then, in order to achieve the wind-drive wave dynamic rendering, this paper proposes a dynamic wave rendering method based on the multi-scale ocean surface grid model to support real-time wind field updating. At the same time, considering the effect of repairing grid crevices on the system efficiency, this paper presents an efficient method for repairing ocean surface grid crevices based on the characteristics of ocean grid and GPU technology. At last, the feasibility and validity of the method are verified by the comparison experiment. The experimental results show that the proposed method is efficient, stable and fast, and can compensate for the lack of function of the existing methods, so the application range is more extensive.
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