在CPU和GPU上分别以Tile和Patch为基础实现地形LOD(level of detail)的自适应简化;提出在Hull Shader上基于Patch边界的细分系数计算模型
确保了Patch细分时的无缝连接;给出了Domain Shader上置换贴图的处理过程
以实现细分顶点的高程纹理映射;并且采用了两级视锥体裁剪机制
减少了渲染数据的冗余量。实验结果表明
该算法具有较好的屏幕空间自适应性和渲染性能
能够在输入粗糙网格的基础上
渲染输出高分辨率几何细节特征的地形模型。
Abstract
In order to render large-scale terrain on graphics processing units (GPU)using hardware-accelerated tessellation
a screen-space adaptive tessellation algorithm for terrain rendering is presented. The triangulation is performed entirely on the GPU
based on analyzing the principle of terrain tessellation. The proposed approach organizes the terrain data hierarchically by tiles and patches
which is the base for a terrain LOD simplification approach processed separately on the CPU and GPU. The edge-based tessellation LOD model for each patch is constructed to compute the tessellation factors in the Hull Shader for the water tightness surface. The procedure for terrain displacement mapping in the Domain Shader is designed to offset and transform each vertex height. Furthermore
a two-level view frustum culling mechanism is used to minimize the data to be rendered. The experimental results show that the algorithm has better screen-space adaptivity and rendering performance. It can produce the terrain model with high resolution geometric details in spite of inputting coarse triangle meshes.