| Summary: | 碩士 === 國立清華大學 === 資訊工程學系 === 89 === In the field of global illumination, the radiosity method has been used to produce some of the most realistic image. However, the cost of its computation time is too much so that it’s not 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 scene.
The most time consuming stage of traditional hierarchy radiosity is visibility testing. In our first approach, we estimate the difference of energy transferred from the links after the scene modified. By ignoring insignificant links, the numbers 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 region in the whole scene. Then, link’s visibility can approximated rapidly by querying it’s associated visibility buffers.
In our third approach, we propose ray buffer data structure extended from visibility buffer to deal with complex scene radiosity which always contains huge numbers of links. The ray buffer data structure stores not only visibility but also energy distribution. Through these information and appropriate energy transfer methods, energy can be redistributed rapidly after dynamic objects are modified which is irrelevant to the amount 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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