一种基于顶点纹理的LOD地形渲染算法

Shader Mode 3.0引入的Vertex Shader Fetch是GPU可编程图形渲染技术发展的又一重要进展,基于该技术提出了一种新的地形渲染算法.算法主要特点是将地形高程数据组织成单通道纹理存放于显存,用于支持视点跟随的LOD地形渲染.绘制阶段,CPU端只需输入平坦的嵌套状的网格,GPU端首先根据当前视点参数计算该网格顶点的实际二维位置坐标,使用该坐标从地形纹理中采样出该顶点的高程值,这样平坦网格的顶点获取到实际的三维坐标值,图形渲染管线将继续处理直至输出显示.如此安排绘制流程可以彻底消减CPU计算负载,转而充分运用GPU高数据处理能力和可编程特性.实验表明,使用本算法绘制地形,效果逼真、绘制效率大大高于传统LOD地形绘制算法.

LOD Terrain Rendering Algorithm Based on Vertex Texture

Vertex Shader Fetch introduced by Shader Mode 3.0,is an important progress of GPU(Graphic Process Unit).Based on this technology,a new terrain rendering algorithm was proposed.The main feature of this algorithm is that terrain elevation data is reformed into a lumen texture to support viewpoint fallowed LOD(Levels of detail) terrain rendering.In real-time rendering phase,what CPU does is just sending a flat and nested grid to GPU,while GPU computes the real 2D coordinate for every vertex depending on current view parameters,using such coordinate to fetch elevation value from the lumen texture.After that,three coordinate value of a vertex are ready,GPU continues to do the rest operation to show the terrain grid.To arrange render operation like that,not only computing load of CPU is reduced thoroughly,but also powerful computing capability of GPU and its feature of Programmable are applied.Experimental results show that,to do Terrain rendering by this algorithm,while getting realistic rendering effect,efficiency is much higher than traditional LOD Terrain Rendering Algorithm.