GPU Based 3D Scene Ambient Occlusion Design And Implement

Ambient occlusion is a method to approximate how bright light should be shining on any specific part of a surface. For instance, the narrow area of an object is darker than the wide area. By analyzing the theory of ambient occlusion, this thesis will explore the ways to achieve the implementation of ambient occlusion algorithms. In order to improve the efficiency of ambient occlusion rendering algorithms, the series of algorithms about screen-space ambient occlusion is studied. What’s more, the practical significance of related formulas and the current inadequacies of this theory are also analyzed. Finally, this thesis tries to find out a new way to solve the existing deficiencies of current screen-space ambient occlusion algorithms by dealing with various kinds of influence factors. The aim of this thesis is to put forward an improved GPU-based integral way of screen-space occlusion algorithm.In the study of this thesis, there are three stages. In the first stage, the implementation process of the existing screen-space ambient occlusion algorithms is studied. In the second stage, the impact factors of existing screen-space ambient occlusion algorithms and the role of each factor in the final rendering effect are analyzed. In the third stage, by analyzing the deficiencies of existing screen-space ambient occlusion algorithms, a new integration way, which combines two types of environmental impact factors, is proposed. In order to facilitate the analysis of actual impact of occlusion factors to rendering effects, an application program, which can render the ambient occlusion effects in real-time, is developed. The application of this program can adjust the factors of ambient occlusion algorithms in real-time. By observing the values of impact factors, the practical relations between the impact factors and the screen-space ambient occlusion algorithms can be easily understood.The main results of the study are twofold: First, an application program, which can render GPU-based screen-space ambient occlusion effects in real-time, is put forward. The use of it can adjust the ambient occlusion factors timely. Second, based on the research and analysis of the existing screen-space ambient occlusion algorithms, combined with the analysis of impact factors, a mixed ambient occlusion integral way is proposed. By using application to adjust the impact factors in real-time, it can be known that the integral way not only affects the quality of ambient occlusion rendering, but also determines the sampling methods of integral key points. While the sampling methods directly decides the efficiency of the screen-space ambient occlusion algorithms. By using the new integration methods, the accuracy of screen-space ambient occlusion algorithm is improved. As can be seen from the comparison of ambient occlusion effects, the new approach proposed can achieve a good rendering quality.