Research And Implementation Of Real-time Global Illumination Algorithm Based On Ray Tracing

Generally,computer graphics algorithm is used to simulate three-dimensional virtual scenes on computers.In order to simulate a better three-dimensional scene and realize the real ray effect,the global illumination model is usually used to calculate the scene illumination.As an important field of computer graphics,global illumination algorithm has been attracting research scholars' attention for many years.Different from the traditional local illumination algorithm,the global illumination algorithm also considers the light intensity contributed by the indirect ray caused by refraction or reflection,in addition to calculating the light intensity contributed by the direct ray in the scene.Therefore,global illumination produces far higher rendering and drawing results than those by local illumination.Ray tracing is one of the most representative global illumination algorithms,which is implemented based on physical optics and mathematical knowledge.Compared with the local illumination model algorithm which only realizes partial illumination effect calculation,the global illumination model based on ray tracing can realize entire illumination effect calculation.In theory,the scene effect can be simulated factually by the ray tracing algorithm,which has typical significance for the research of ray tracing algorithm.However,when performing ray tracing calculations,a large number of intersection calculations between rays and objects need to be performed,so the algorithm has certain limitation in the real simulation applications.Therefore,to ensure the continuity of the visual effect in the real scene simulation,the acceleration structure algorithm is researched to improve its efficiency.For the global illumination algorithms,the simplification of the illumination model and the research of the acceleration structure algorithm have practical significance in improving the realism and real-time performance of the algorithm.With the popularity of GPU,parallel technology has also received widespread attention.In the field of computer graphics,the existing parallel technology has also been extensively researched.Among them,the application of parallel acceleration structure algorithms has become a new trend to improve the speed of ray tracing.In this thesis,the main research innovations are listed as follows:1)In terms of the sense of reality of the ray tracing algorithm,aiming at the classic model which cannot render and draw different materials for shadow effects,a more targeted optimization ray tracing illumination model was proposed to improve the global illumination algorithm,so that the model has a better sense of reality in the rendering and drawing of shadow effects.At the same time,the termination conditions of partial model materials were optimized to simplify the generation of rays and improve the calculation speed.2)In terms of the real-time performance of the ray tracing algorithm,aiming at the performance of traditional acceleration structure in construction speed and quality balance,this thesis improved the ray tracing acceleration structure,which utilizes the Morton code based spatial algorithm to sort the scene primitives,and the optimized search and merge process based on the approximate agglomerative clustering algorithm.The optimized algorithm has better construction quality and speed,the use of optimized acceleration structure algorithm to simplify the intersection calculation can make the ray tracing algorithm have better real-time performance.3)In terms of algorithm implementation,this thesis performs system design based on the above-mentioned sense of reality and real-time optimization algorithms.Specifically,and the global illumination system was constructed as a whole to expand the application scope of the algorithm.Then test and analyze the implementation results of global illumination and the rendering and drawing of different materials in the sense of reality.Beyond that,test and analyze the average frame rate results of rendering and drawing in real-time performance.