| In the scopes of entertainment, reproducing of historical site, simulating and military affairs, the users demand the feeling of immersing themselves in the virtual scene increasingly. At the same time, with the gradual upgrading of hardware equipment capacity, the software developers never stop exploring and practicing on the realistic technology. The expressive force and immersion in 3D roaming scene are much better than those in 2D scene, so the real-time rendering of 3D roaming become hotspot recent years. The real-time rendering of 3D roaming is not only the core technology in 3D virtual System, but also determines the realism the users experience directly, In this paper, the major work and research in real-time rendering of 3D scene roaming as follows:(1)Focusing on the sorting of renderable objects in large scene, we propose a sorting method based on the rendering state. Firstly, we define a pair structure, the key is the material information and the value is the object information. And then we analyze the material script and the object information, and fill the key with the information. Finally, we sort the materials based on the meaning of each bit.(2)Focusing on the rendering of large-scale terrain, we propose a GPU based LOD approach. Firstly, we use the quadtree structure to organize the terrain data. Secondly, we deal with the transition zone to eliminate the crack between meshes in different LOD by vertex program. Finally, we package four single-channel texels to a four-channel texel to reduce the consumption of low-end graphics card in sampling heightmap in vertex program.(3)Focusing on the problems encountered and the project requirements in North China University of Technology Virtual Campus, we introduce the scene loading, roaming and navigation methods we use. Finally, demonstrates the major functions about NCUT Virtual Campus. |
