The Research Of Technology In OpenGL-based Real-time Rendering Of Big Scale Scene

Virtual Reality (VR) Technology is developing so fast nowadays. It is widely used in medical, military, manufactory industry an so on. 3D animation rendering technique is one of the core techniques of VR. Rendering is one of the most important research area in 3D animation rendering techniques. It is also the last process in the graphic pipeline. The last display effect if generated by it. Computer graphic is becoming more and more complex since the 20th century, and rendering is becoming an important technique.This thesis takes the project "Catching Insects", which is one of the child projects in the key project, cooperated by Guangdong Science Center and EI department in Huazhong University of Science and Technology, as a background. I made a deep research on how to improve the rendering efficiency in real-time 3D animation and found several available techniques in the practice. This thesis will first give a brief introduction on the base of the theory, including 3D computer graphics, OpenGL programming and GPU based graphic programming technologies. Then the architecture design and the particular design of the scene rendering module will be presented. After that, in the theory basement, this thesis will introduce every detail of the key techniques in the scene rendering module.This thesis first realized the static model rendering by display list technique, and designed the algorithm for calculating the normal vector and height above see level in the non model vertex point. Then it designed the large-scale waving grasses rendering program make use of the GPU vertex processor, so that to share lighten the work for CPU and to improve the rendering efficiency. It also invented the static shadow masking technique make use of the GPU fragment processor. It achieved a quite good effect of shadow for static object in the premise that the rendering effect is not affected. This thesis designed a LOD algorithm for the waving grass animation. It improved the rendering efficiency greatly with only slight reduce in rendering effect. These rendering techniques have all been realized by OpenGL programming and it is proved that they can achieve pretty good vision effect and real-time rendering efficiency. This thesis also gave the system test results and the analysis for the results.