【作者】 彭庸；

【导师】 杨威； 张建奇；

【作者基本信息】 西安电子科技大学 ， 物理电子学， 2009， 硕士

【摘要】 真实感是场景仿真中衡量仿真效果的一个重要指标,并随着软、硬件条件的不断发展而越来越受到重视。本文从地形生成算法和纹理映射技术两个方面论述如何提高场景仿真的真实感。在地形建模方面,基于前人的工作基础,通过结合影响地形细节的视点相关、地形精度、地形粗糙度三种因素,构建一种新的判断准则,来约束基于改良的受限四叉树的LOD(level of detail)地形结构的建立,同时给出相应的数据结构和具体的地形生成算法。而在纹理映射方面,着重论述如何减弱或消除小纹理映射技术中存在的问题,例如来自于不同纹理之间边缘过渡的突兀感、小纹理映射在大区域带来重复性、视距变化引起的纹理虚化或闪烁等,通过对地形数据进行一定的处理得到纹理的混合因子,从而混合出整个地形的地貌纹理数据,改善地形场景仿真的真实感。最后通过OpenGL(Open Graphics Library)实现场景仿真,验证了本文方法在满足渲染速度情况下提高了仿真的真实感。更多还原

【Abstract】 The third dimension is an important guideline to measure simulation effect in scene simulation, which is more and more regarded with the continuous development of software and hardware. This paper discusses that how to enhance the third dimension of scene simulation from the two aspects of terrain algorithm and texture mappings technique.On the facet of terrain modeling, a new metric is established to restrict the building of LOD(level of detail )terrain structure which is based on improved restricted quad-trees on the foundation of predecessors’work. Simultaneity, relevant data-structures and detailed algorithms for generating 3D terrain were presented. Three factors affecting the terrain details were considered, which are the view dependence, terrain precision and terrain roughness.On the facet of texture mapping, how to lower or eliminate the problems existing in small-texture mappings technique is discussed, such as the abrupt sense coming from the marginal transition between different texture, the repetition brought by the small texture mapped in the large scale area, the mosaic effect or flicker of texture brought by the change of viewing distance and so on. The physiognomy texture data of all the terrain are blended by the texture mixable factor through treating with terrain data, which improves the third dimension of terrain scene simulation.Finally, the scene simulation are carried out by OpenGL(Open Graphics Library), which validate that the method proposed in this paper enhance the third dimension of simulation and meet the rendering speed.更多还原