Research On Scene Rendering Technology Of 3D Game Rendering Engine Based On LOD

LOD (Level of Detail) algorithms are commonly used in the field of terrain visualization, but they are not specifically optimized for game scene. The LOD algorithms used in game terrain rendering are not specifically optimized for the latest GPU (Graphic Processing Unit) either. In order to achieve good performance, traditional scene rendering algorithms often use low-precision terrain models. As a matter of fact, they can not create vivid, realistic and shocking game scene.Based on these facts, the main works of this thesis are as follows:In this thesis, an optimized LOD scene rendering algorithm based on geoclipmap is designed and implemented. The algorithm extends geoclipmap which is proposed by Hoppe. By means of combining with the characteristics of latest GPU and storing geometric information in the form of terrain texture, geometric information, texture and normal map are stored in unified structure. This allows almost all calculations to be performed on GPU, so a large amount of CPU (Central Processing Unit) computing times can be used to deal with other computing things. Then, the sphere culling and fog technology which are commonly used in game engine are used to solve the problem of complexity in rendering the non-elevation models in game scene. Comparative experiments with other terrain rendering techniques which are commonly used in game engine are performed, and the results confirm that this algorithm speeds up scene rendering rate.This thesis also proposes a new method based on stencil buffer and blending to transparentize the overlapped region between game characters and obstacles. First, this method establishes a query queue which is used for querying obstacles by overlay testing of projected pixels, and then set up stencil buffer pixels which the characters are occupied according to the order of scene rendering. In order to achieve transparent effect, a blend formula for blending pixels of the characters and the pixels of the obstacles is designed. The experiment shows that gamers can control the game characters better than ever. The obstacles which block the game characters will also be rendered correctly at the same time.At last, three types of bulletin board technologies are introduced. Then a dynamic bulletin board algorithm which is used for rendering 3D trees is proposed. The proposed algorithm samples a 3D tree by precomputation, and then uses interpolation of precomputed images to get the final display image. The interpolation is based on view prospect. This algorithm uses precomputed high-quality images to render 3D trees, so the cost of scene rendering is very low.Finally, the entire research is summarized, and the issues for future work are also presented.