Real-time Indirect Illumination and Soft Shadows in Dynamic Scenes Using Spherical Lights

Information

• Publication Type: Journal Paper (without talk)
• Workgroup(s)/Project(s):
  • TreeLumination
• Date: October 2008
• Journal: Computer Graphics Forum
• Number: 8
• Volume: 27
• Pages: 2154 – 2168
• Keywords: global illumination, precomputed radiance transfer, soft shadows

Abstract

We present a method for rendering approximate soft shadows and diffuse indirect illumination in dynamic scenes. The proposed method approximates the original scene geometry with a set of tightly fitting spheres. In previous work, such spheres have been used to dynamically evaluate the visibility function to render soft shadows. In this paper, each sphere also acts as a low-frequency secondary light source, thereby providing diffuse one-bounce indirect illumination. The method is completely dynamic and proceeds in two passes: In a first pass, the light intensity distribution on each sphere is updated based on sample points on the corresponding object surface and converted into the spherical harmonics basis. In a second pass, this radiance information and the visibility are accumulated to shade final image pixels. The sphere approximation allows us to compute visibility and diffuse reflections of an object at interactive frame rates of over 20 fps for moderately complex scenes.

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BibTeX

@article{guerrero-2008-sli,
  title =      "Real-time Indirect Illumination and Soft Shadows in Dynamic
               Scenes Using Spherical Lights",
  author =     "Paul Guerrero and Stefan Jeschke and Michael Wimmer",
  year =       "2008",
  abstract =   "We present a method for rendering approximate soft shadows
               and diffuse indirect illumination in dynamic scenes. The
               proposed method approximates the original scene geometry
               with a set of tightly fitting spheres. In previous work,
               such spheres have been used to dynamically evaluate the
               visibility function to render soft shadows. In this paper,
               each sphere also acts as a low-frequency secondary light
               source, thereby providing diffuse one-bounce indirect
               illumination. The method is completely dynamic and proceeds
               in two passes: In a first pass, the light intensity
               distribution on each sphere is updated based on sample
               points on the corresponding object surface and converted
               into the spherical harmonics basis. In a second pass, this
               radiance information and the visibility are accumulated to
               shade final image pixels. The sphere approximation allows us
               to compute visibility and diffuse reflections of an object
               at interactive frame rates of over 20 fps for moderately
               complex scenes.",
  month =      oct,
  journal =    "Computer Graphics Forum",
  number =     "8",
  volume =     "27",
  pages =      "2154--2168",
  keywords =   "global illumination, precomputed radiance transfer, soft
               shadows",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2008/guerrero-2008-sli/",
}