Realistic Scene Rendering Method And Its Application Based On Ray Tracing

Realistic graphics display has been the goal of the study of computer graphics. Ray tracing technology is a hotspot research of realistic graphics. It can simulate various physical phenomena like reflection,refraction, shadow etc. So it is widely used in the optical reflection simulation of three-dimensional(3D) scene. Ray tracing algorithm is simple and easy to be implemented. Visual effects of pixel level can be achieved by adopting ray tracing. It is an important light and shadow technology in game, film, aerospace and other industries.Combined with bidirectional reflectance distribution function(BRDF) of objects' surfaces, in ths paper, vertex shading of the three-dimensional model with ray tracing algorithm based on global radiosity is applied in the simulation of optical reflection characteristics of the space target. Primary innovative works about this thesis can be summarized as follows:1. Theories of common used BRDF models like Lambert, Phong and Cook-Torrance are analyzed in this paper. Principle of ray tracing is illustrated, and processes of both Whittled Ray Tracing and Monte Carlo Ray Tracing are discussed. In addition, current mainstream acceleration methods of ray tracing are summarized.2. Vertex shading of the three-dimensional model with ray tracing algorithm based on global radiosity is proposed to simulate surface's optical reflection characteristics of the space target which takes the earth as background. The key technologies for the simulation of the reflection characteristics are studied and realized,such as the camera optical system modeling, the target geometry modeling, the target reflection characteristics modeling and the simulation of target imaging.3. A simulation system of the optical reflection characteristics of one space target's surface is designed and realized based on key technologies mentioned above. The design of database is completed successfully, as well as the main classes or interfaces, and the functional modules. The development of the whole system is accomplished with the 3D engine library called OpenSceneGraph.Simulation results demonstrate that authenticity and efficiency can be obtained by the improved method of vertex shading with ray tracing based on global radiosity associated with BRDFs of both the space target's surface and the surrounding scenery.