The Research Of Real-time Shadow Algorithms Based On OpenGL

The generation of realistic images has been the focus and hot field of computer graphics research, In realistic image generation technology, real-time shadow rendering technology is the key technology, it determines the final quality of the images generated. It is critical for realism and immersion of the image. With the development of the computer, the effects of real-time shadow have came form impossible or simply analog earlier to today's high-efficiency simulation and real simulation.Real-time shadow algorithm in the current study, the research focus mainly concentrated in the shadow maps and shadow body algorithm, while the surface mapping algorithm proposed because of its early years, with a milestone, it is also have the value of studying and learning. The applicability of the original plane mapping algorithm is too narrow, it can only be used in teaching. Shadow maps algorithm is an image space algorithm, the biggest shortcoming is the aliasing problem; the shadow volume algorithm is an object space algorithm, although there is no aliasing problem, but the efficiency of the algorithm with the model number and complexity is a linear proportional relationship. In the first of these three algorithms by theoretical analysis and research, analysis the advantages and shortcomings of these algorithms, when is comes to the algorithms of shadow maps and shadow volume, we use the method of partly comparative study, analysis these two algorithms for computing resolution and sensitivity of the processor and analyze where is the bottleneck. By the basic geometric method and the functions provided by OpenGL, the algorithm was improved to overcome the shortcomings to some extent. In order to overcome the defects in shadow maps and shadow volume algorithm, we combine these two algorithms to form a new real-time shadow rendering algorithm, not only to overcome the aliasing problem, but also solve the shadow of the volume structure that existed when large amounts of data calculation and a large area filled which bring efficiency problem.Based on OpenGL2.1 programming interface, we use the experimental results to prove the theoretical analysis, prove the effect of rendering algorithm performance and the key factors..