| Summary: | 碩士 === 國立清華大學 === 資訊工程學系 === 88 === In the study of global illumination, the radiosity method has been known for being able to synthesize photo-realistic images. However, its computation time is too long to be applicable to dynamic environments, that is, virtual scene whose objects are subject to be modified interactively. In this thesis, we propose three approaches to accelerate the computation of traditional radiosity method for dynamic environments.
It is known that the most time consuming stage of traditional hierarchical radiosity is the visibility testing. In our first approach, we estimate the difference of energy transferred along link after the scene change. By ignoring insignificant links, the number of links’ visibility testing can be greatly reduced. In the second approach, we propose visibility buffer data structure to approximate link visibility. The basic notion of visibility buffer is to store the visibility distribution of each cluster in the scene. Then, link’s visibility can be approximated rapidly by concatenating associated visibility buffers along the link.
In our third approach, we propose ray buffer data structure which is a extension of visibility buffer. The ray buffer data structure stores not only visibility but also energy distribution. Through buffered information and appropriate energy transfer schemes, energy can be redistributed rapidly after dynamic objects are modified. This approach is independent to the number of links.
Finally, some empirical tests are given to show that our proposed approaches are not only feasible but also achieve interactive frame rate.
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