Real-time soft shadows with cone culling

Louis Bavoil, Cláudio T. Silva

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We have developed a new physically-based technique for computing soft shadows from a shadow map for spherical lights. Shadow-map samples unprojected into world-space (micro-patches) are culled against a shadow cone wrapping all the possible shadow rays from the light to the surface location. Because of this volumetric test, the algorithm handles self-shadowing more robustly than traditional shadow mapping. The amount of shadowing contributed by each culled micro-patch is approximated by the solid angle subtended by the bounding sphere of the micro-patch over the solid angle of the light source. We describe a real-time implementation running entirely on a GPU. For each image pixel to shadow, the algorithm projects the pixel onto the near plane of the light frustum, and looks up occluding micro-patches in a dynamic disk kernel. To guarantee constant frame rates, the kernel is sampled using a fixed number of samples per pixel. Our results compare favorably to ray-tracing for images with no overlapping shadows.

Original languageEnglish (US)
Title of host publicationACM SIGGRAPH 2006
Subtitle of host publicationSketches, SIGGRAPH '06
StatePublished - 2006
EventACM SIGGRAPH 2006: Sketches, SIGGRAPH '06 - Boston, MA, United States
Duration: Jul 30 2006Aug 3 2006

Publication series

NameACM SIGGRAPH 2006: Sketches, SIGGRAPH '06


OtherACM SIGGRAPH 2006: Sketches, SIGGRAPH '06
Country/TerritoryUnited States
CityBoston, MA

ASJC Scopus subject areas

  • Computer Graphics and Computer-Aided Design
  • Computer Vision and Pattern Recognition
  • Human-Computer Interaction


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