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Intersection fields for interactive global illumination. Pacific Graphics 2005 Zhong Ren Wei Hua Lu Chen Hujun Bao State Key Laboratory of CAD&CG Zhejiang University, P.R. China. Overview. Interactive global illumination Illumination engineering Animation preview Visibility bottleneck
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Intersection fields for interactive global illumination Pacific Graphics 2005 Zhong Ren Wei Hua Lu Chen Hujun Bao State Key Laboratory of CAD&CG Zhejiang University, P.R. China
Overview • Interactive global illumination • Illumination engineering • Animation preview • Visibility bottleneck • Intersections, intersections… • Intersection(O(log(n))) to Query(O(1)) • GPU?
Previous Work • Radiosity • Illumination network[Bucklew89] • Monte Carlo Method • Selective photon tracing • GPU based photon mapping[Purcell2003] • Global ray-bundle tracing[Kalos98, 99, 03]
Intersection field – the idea Ray-scene intersection points are places where light-object interactions take place.
… … Intersection field – the idea
Parameterization Slice(a, b) (c, d) l(a, b, c, d) Base plane (a, b)
Discretization Slice(ai, bj) (ck, dm) l(i, j, k, m) (ai, bj)
Generating IF Object Space Screen Space Rasterize Line Space 2-step scan conversion
… … Data organization Intersection Record Line Record Index Table Page Record (p, l, T) (i, j, k, m) (i, j, k) (x|y|z, T)
… … … … … … Local/Global IF
Computation model Local Irradiance Map Visibility Ratio Map Indirect Irradiance Map
Intersection field Scene data Computation model Synthesizer LIM VRM IIM LI Shader Photon Tracer Visibility Solver IF Generator
Sk LIM – H(M,Sk) M Local Irradiance Map • Pixel Shader • Divide Sk into patches • Render-to-texture • Updating issue
Visibility Ratio Map Sk VRM – V(M,Sk) • Query IF for visibility sample • Reconstruction • Render-to-texture • Updating issue M
IIM – G(M) M Indirect Irradiance Map • Query IF for intersection points • Accumulation • Render-to-texture
Results • 93M Lines (76x127x76x127) • 72.6MB/113.0MB Intersection Field • ~35,000 Photons
Contribution • Visibility Representation • Rendering Framework
Limitation • Storage cost • High frequency effect