Research Of Acceleration Structures For Dynamic Scenes Based On Ray Tracing

Ray tracing algorithm is a major rendering algorithms that can generate high-reality images, has been widely used in areas of static rendering applications because of its simple conception and easily implementation. With the development of computer hardware and the research of new algorithm, ray tracing algorithm has been made a good rendering performance in the interactive system and dynamic scenes. However, in the dynamic and complex scenes, due to the complexity of objects in scenes and dynamic update features of scenes, the real-time rending of ray tracing is still a central issue and difficulty.To solve this problem, the paper rely on the properties of objects which have different types of movement.Three classes of objects are distinguished:static objects, local dynamic objects, dynamic objects. To construct a proper acceleration structure for each class based on the characteristics of three types of objects. Global octree are the acceleration structure of choice for static geometry of scenes and are commonly built by employing the max depth of octree to determine the termination of slipping. For local dynamic geometry, to construct a local octree and its construction can be realized by increasing the depth of global octree. For dynamic geometry, a two-level bounding volume hierarchy (BVH) is introduced that efficiently supports its rigidly animation in scenes.The paper produces a three-level hierarchy organization pattern to organize the multi-acceleration structures of dynamic scenes. The top-level is global octree acceleration structures to organize all static scenes. The middle-level is local octree for local dynamic objects and BVH for dynamic objects. Both two acceleration structures rely on the global octree. The bottom-level is lazy build BVH. These hierarchies are not built upfront but are constructed lazily when a ray traverses them.In the last parts of thesis, we use BART(A Benchmark for Animated Ray Tracing)which provides a set of dates and code frames to make our experiments. We pay close attentions to the two test scenes(Kitchen and Robot) and then we made an comparison with the other two algorithms(BVH+BVH,BVH+Kd-tree) which are both organized in two-level. According to the result dates, we can come to the conclusion that the way to classify the objects in dynamic scenes and to construct a proper acceleration structure for each class and then use three-level hierarchies organization pattern to manage three acceleration structures, can get a better global rendering performance for dynamic scenes containing objects which motion types meet the classification criteria. Meanwhile, solve the real-time rendering problems of dynamic scenes in some extent.