Computer Engineering & Science >
GPUBased Computation and an Implementation Method of Volume Illumination for UnstructuredGrid Data
Received date: 2010-05-12
Revised date: 2010-09-21
Online published: 2011-01-25
Gradient estimation is necessary for illumination effects which play an important role in volume rendering. Compared with the structured grids, it is difficult to estimate the vertex gradient for unstructured grids due to the complicated topology. Futhermore,realtime rendering can be hardly achieved due to the computation complexity of the resampled point gradient and the difficultity of implemention on GPUs. As a result, most of the unstructuredgrid volumes have not been lit. This paper presents a method to estimate the vertex gradient with high precision for unstructured grids. It employs the volumeweighted extrapolation and the inversedistance extrapolation to compute a vertex gradient using a group of cell gradients estimated by the Green theorem. Meanwhile, to compute the gradient at a resampled point, we present an efficient method based on the cell divergence which makes the cost much lower than the recent method of fulllinear interpolation。The realtime performance of our algorithm even for the relative large data sets can be achieved by its GPU implementaion with the aid of a welldesigned data structure.
MA Qianli,XU Huaxun,YUE Kai,LI Sikun . GPUBased Computation and an Implementation Method of Volume Illumination for UnstructuredGrid Data[J]. Computer Engineering & Science, 2011 , 33(1) : 82 -87 . DOI: 10.3969/j.issn.1007130X.2011.
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