A Light Hierarchy for Fast Rendering of Scenes with Many LightsEric Paquette, Pierre Poulin, and George Drettakis In Computer Graphics Forum (Proceedings of Eurographics '98) |
We introduce a new data structure in the form of a light hierarchy for efficiently ray-tracing scenes with many light sources. An octree is constructed with the point light sources in a scene. Each node represents all the light sources it contains by means of a virtual light source. We determine bounds on the error committed with this approximation to shade a point, both for the cases of diffuse and specular reflections. These bounds are then used to guide a hierarchical shading algorithm. If the current level of the light hierarchy provides shading of sufficient quality, the approximation is used, thus avoiding the cost of shading for all the light sources contained below this level. Otherwise the descent into the light hierarchy continues.Our approach has been implemented for scenes without occlusion. The results show important acceleration compared to standard ray-tracing (up to 90 times faster) and an important improvement compared to Ward's adaptive shadow testing.
@InProceedings{Paquette:1998:LHF, author = "Eric Paquette and Pierre Poulin and George Drettakis", title = "A Light Hierarchy for Fast Rendering of Scenes with Many Lights", editor = {N. G\"obel and F. Nunes Ferreira (guest editor)}, pages = "63--74", booktitle = "Computer Graphics Forum (Eurographics '98 Conference Proceedings)", year = "1998", organization = "Eurographics", month = sep, note = "held in Lisbon, Portugal, 02-04 September 1998", }
Adobe PDF version of the paper.
Adobe PDF version of the presentation of the paper at the Eurographics '98 conference in Lisbon.
Page with graphics and brief description of the method.
There is an error in the derivation of the specular bound in appendix A.
The bound presented in section 4.3.1, the statistics and conclusions are all
correct. It is only in the appendix that there is an error.
The online version of the paper is correct but the version in the proceedings
is incorrect.
The correction of that error is
available in the form of a PDF file
(requires Acrobat Reader 3.0).