为提高大规模地形实时渲染时的绘制效率,提出一种使用地形分块作为处理单元的批LOD算法。在预处理阶段,将多分辨率的地形数据划分成适于GPU批处理的分块,使用四叉树进行分块的有效组织。在此基础上,提出一种基于分块绘制的LOD误差标准,简化层次选取的计算量,通过增加"裙"和进行几何变形实现了层次间的有效过渡;实时绘制过程中,使用视锥裁剪减少进入图形硬件的数据量,利用地形四叉树列表和预测机制实现地形数据的有效加载管理。实验结果表明,本文算法能够充分发挥图形硬件的性能,具有较高的地形实时渲染效率。

To make the real-time rendering of large scale terrain more efficient,a batched LOD algorithm is proposed in which terrain blocks are handled as the processing unit.In the preprocessing stage,multi-resolution terrain data is partitioned into regular blocks with predefined sizes.These blocks are organized in the form of quadtree.Based on this form,an error metrics for LOD selection is designed in order to simplify the computation of level decision.Then by the means of adding skirts and geometry morphing,different levels are transited without a visual distortion or popping.When terrain is being rendered,frustum culling is used to reduce data transmitted to graphics hardware.To efficiently implement data loading and datasets management,terrain quadtree lists and a prediction strategy are introduced.From the result of final simulation,it can be seen that the algorithm can fully harness the power of current graphics hardware and reach higher rendering rates.