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A Vector Approach for Global Illumination in Ray Tracing
Author(s) -
Zaninetti Jacques,
Serpaggi Xavier,
Péroche Bernard
Publication year - 1998
Publication title -
computer graphics forum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 120
eISSN - 1467-8659
pISSN - 0167-7055
DOI - 10.1111/1467-8659.00262
Subject(s) - ray tracing (physics) , global illumination , distributed ray tracing , computation , specular reflection , caustic (mathematics) , computer science , ray , interpolation (computer graphics) , normal , euclidean vector , computer vision , computer graphics (images) , artificial intelligence , optics , geometry , mathematics , algorithm , physics , rendering (computer graphics) , surface (topology) , image (mathematics)
This paper presents a method taking global illumination into account in a ray tracing environment. A vector approach is introduced, which allows to deal with all the types of light paths and the directional properties of materials. Three types of vectors are defined: Direct Light Vectors associated to light sources, Indirect Light Vectors which correspond to light having been diffusely reflected at least once and Caustic Light Vectors which are associated to light rays emitted by sources and reflected and/or transmitted by specular surfaces. These vectors are estimated at a small number of points in the scene. A weighted interpolation between known values allows to reconstruct these vectors for the other points, with the help of a gradient computation for the indirect component. This approach also allows to take uniform area light sources (spherical, rectangular and circular) into account for all the types of vectors. Computed images are thus more accurate and no discretizing of the geometry of the scene is needed.