Numerical methods and software
Numerical methods and software
A Ray tracing algorithm for progressive radiosity
SIGGRAPH '89 Proceedings of the 16th annual conference on Computer graphics and interactive techniques
Discontinuity Meshing for Accurate Radiosity
IEEE Computer Graphics and Applications
Modeling global diffuse illumination for image synthesis
Modeling global diffuse illumination for image synthesis
Fast object-precision shadow generation for area light sources using BSP trees
I3D '92 Proceedings of the 1992 symposium on Interactive 3D graphics
A fast shadow algorithm for area light sources using backprojection
SIGGRAPH '94 Proceedings of the 21st annual conference on Computer graphics and interactive techniques
Fast computation of shadow boundaries using spatial coherence and backprojections
SIGGRAPH '94 Proceedings of the 21st annual conference on Computer graphics and interactive techniques
Fast calculation of soft shadow textures using convolution
Proceedings of the 25th annual conference on Computer graphics and interactive techniques
Proceedings of the 1999 conference on Graphics interface '99
Selective Culling of Discontinuity Lines
Proceedings of the Eurographics Workshop on Rendering Techniques '97
SIGGRAPH '84 Proceedings of the 11th annual conference on Computer graphics and interactive techniques
ACM Transactions on Graphics (TOG)
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The problem of computing soft shadows with area light sources has received considerable attention in computer graphics. In part, this is a difficult problem because the integral that defines the radiance at a point must take into account the visibility function. Most of the solutions proposed have been limited to polygonal environments, and require a full visibility determination preprocessing step. The result is typically a partitioning of the environment into regions that have a similar view of the light source. We propose a new approach that can be successfully applied to arbitrary environments. The approach is based on the observation that, in the presence of occluders, the primary difficulty in computing the integral that defines the contribution of an area light source, is that of determining the visible domain of the integrand. We extend a recent shadow algorithm for linear light sources in order to calculate a polygonal approximation to this visible domain. We demonstrate for an important class of shadowing problems, and in particular, for convex occluders, that the shape of the visible domain only needs to be roughly approximated by a polygonal boundary. We then use this boundary to subdivide an area light source into a small number of triangles that can be integrated efficiently using either a deterministic solution, or a low degree numerical cubature.