A Light Hierarchy for Fast Rendering of Scenes
with Many Lights
Poulin, and George
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
Image synthesis, rendering, ray-tracing, hierarchy, illumination, reflection,
Phong, bounds, clustering, octree.
author = "Eric Paquette and Pierre Poulin and George Drettakis",
title = "A Light Hierarchy for Fast Rendering of Scenes with
editor = "M. Gobel and F. Nunes Ferreira",
pages = "63--74",
booktitle = "Computer Graphics Forum (EuroGraphics '98 Conference
year = "1998",
organization = "EuroGraphics",
month = sep,
note = "held in Lisbon, Protugal, 02-04 September 1998"
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