9.3 Thesis Group 3. Ray reuse with virtual light sources
9.3.2 Thesis 3.2 Dynamic indirect lighting with precomputed light paths
points to reference points, and the light appearing at reference points due to unit irradiance arriving at an entry point is stored in a precomputed Light Path Map. The computation of the LPM uses the virtual light sources method itself. When rendering the scene, LPM entries can be combined according the to actual lighting, yielding indirect illumination results at reference points. For surface points between reference points, the results are interpolated. The algorithm works on the GPU, offering real-time indirect illumination. [I1, J1, I7, D4, B1]
Own publications
[B1] L. Szirmay-Kalos, L. Sz´ecsi, and M. Sbert. GPU-based Techniques for Global Illumination Effects. Morgan & Claypool, San Francisco, USA, 252 pps. 2008.
Citations: 2.
[D1] L. Sz´ecsi. An Effective Implementation of the K-D Tree. in Graphics Pro-gramming Methods (editor: Jeff Lander), Charles River Media, Hingham, Massachusetts, pp 315-325, 2003. Citations: 5.
[D2] L. Sz´ecsi. Alias-free Hard Shadows with Geometry Maps. in ShaderX5: Advanced Render-ing Techniques (editor: Wolfgang Engel), Charles River Media, HRender-ingham, Massachusetts, pp 219-237, 2007.
[D3] L. Sz´ecsi. and K. Arman. Procedural Ocean Effects. in ShaderX6: Advanced Rendering Techniques (editor: Wolfgang Engel), Charles River Media, Hingham, Massachusetts, pp 331-350, 2008.
[D4] L. Sz´ecsi, L. Szirmay-Kalos, and M. Sbert. Interactive Global Illumina-tion with Precomputed Radiance Maps. in ShaderX6: Advanced Rendering Techniques (editor: Wolfgang Engel), Charles River Media, Hingham, Mas-sachusetts, pp 401-410, 2008.
[D5] L. Sz´ecsi. Instant Radiosity with GPU Photon Tracing and Approximate Indirect Shadows. in ShaderX7: Advanced Rendering Techniques (editor:
Wolfgang Engel), Charles River Media, Hingham, Massachusetts, pp 479-494, 2009.
[F1] A. Barsi, L. Szirmay-Kalos, and L. Sz´ecsi. Image-based Illumination on the GPU. Machine Graphics and Vision, Vol 14., No 2., pp 159-169, 2006. Citations: 3.
[F2] M. Sbert, L. Sz´ecsi, and L. Szirmay-Kalos. Real-time Light Animation. Com-puter Graphics Forum, Vol 23., No 3., pp 291-299, 2004. Citations: 8. IF:
0.801
[F3] L. Sz´ecsi, M. Sbert, and L. Szirmay-Kalos. Combined Correlated and Impor-tance Sampling in Direct Light Source Computation and Environment Map-ping. Computer Graphics Forum, Vol 23., No 3., pp 585-593, 2004. Citations:
12. IF: 0.801
[F4] L. Sz´ecsi and L. Szirmay-Kalos. Efficient Approximate Visibility Testing Using Occluding Spheres. Journal of WSCG, Vol 12., No 3., pp 435-442, 2004.
[F5] L. Sz´ecsi, L. Szirmay-Kalos, and Cs. Kelemen. Variance Reduction for Russian Roulette. Journal of WSCG, Vol 11. No 3., pp 456-463, 2003.
[F6] L. Szirmay-Kalos, T. Umenhoffer, B. T´oth, L. Sz´ecsi and M. Sbert. Volumetric Ambient Occlusion. IEEE Computer Graphics and Applications, pp. 1-13.
2009. IF: 1.398
90
OWN PUBLICATIONS 91 [F7] L. Szirmay-Kalos, T. Umenhoffer, G. Patow, L. Sz´ecsi and M. Sbert. Specular Effects on
the GPU: State of the Art. Computer Graphics Forum, 26:1 pp. 1-24. 2009. IF: 1.107 [F8] L. Szirmay-Kalos and L. Sz´ecsi. Deterministic Importance Sampling with Error Diffusion.
Computer Graphics Forum, 28:4 pp. 1-11. 2009.
[I1] L. Sz´ecsi, L. Szirmay-Kalos, and M. Sbert. Light Animation with Precomputed Light Paths on the GPU. Graphics Interface 2006, Quebeck, Canada. pp 187-194. 2006. Citations: 4.
[I2] L. Sz´ecsi. The hierarchical ray engine. Proceedings of WSCG (Full papers), 2006.
[I3] Sz. Czuczor, L. Szirmay-Kalos and L. Sz´ecsi. Photon map gathering on the GPU. Pro-ceedings of Eurographics (short papers), pp 117-120. 2005. Citations: 1.
[I4] L. Sz´ecsi and L. Szirmay-Kalos. Improved Indirect Photon Mapping with Weighted Im-portance Sampling. Proceedings of Eurographics (short paper), pp 45-52. 2003.
[I5] L. Sz´ecsi and B. Benedek. Accelerating Animation Through Verification of Shooting Walks.
Spring Conference on Computer Graphics, Budmerice, pp 255-261. 2003. Citations: 3.
[I6] L. Szirmay-Kalos, V. Havran, B. Benedek, and L. Sz´ecsi. On the Efficiency of Ray-shooting Acceleration Schemes. Spring Conference on Computer Graph-ics, Budmerice, pp 255-261. 2003. Citations: 21.
[I7] T. Umenhoffer, L. Szirmay-Kalos, L. Sz´ecsi, B. T´oth, and M. Sbert. Partial, Multi-scale Precomputed Radiance Transfer. Spring Conference on Computer Graphics, Budmerice, pp. 87-94. 2008.
[I8] L. Szirmay-Kalos, L. Sz´ecsi, and A. Penzov. Importance Sampling with Floyd-Steinberg Halftoning. Proceedings of Eurographics (short papers), pp 69-72. 2008.
[J1] L. Sz´ecsi. Conservative rasterization of texture atlases. III. Hungarian Con-ference on Computer Graphics and Geometry, Budapest, Hungary, pp 79-85.
2005.
[J2] L. Sz´ecsi and B. Benedek. Improvements on the kd-tree. I. Hungarian Confer-ence on Computer Graphics and Geometry, Budapest, Hungary, pp 165-172.
2002.
[J3] B. Benedek and L. Sz´ecsi. Performance Improvements of Rendering Caustics using Photon Maps in Interactive Ray Tracing. I. Hungarian Conference on Computer Graphics and Geometry, Budapest, Hungary, pp 207-211. 2002.
[J4] L. Sz´ecsi. Procedural Ocean Waves. IV. Hungarian Conference on Computer Graphics and Geometry, Budapest, Hungary, pp 80-87. 2007.
[J5] L. Sz´ecsi and K. Ralovich. Loose kd-trees on the GPU. IV. Hungarian Con-ference on Computer Graphics and Geometry, Budapest, Hungary, pp 94-101.
2007.
[J6] L. Sz´ecsi, L. Szirmay-Kalos, P. Anton. Environment mapping with halftoning 7th Con-ference of the Hungarian Association for Image Processing and Pattern Recognition. Bu-dapest, Hungary, pp. 1-9. 2009.
[H1] L. Szirmay-Kalos, L. Sz´ecsi, and M. Sbert. GPUGI: Global Illumination Effects on the GPU. Eurographics Tutorial, 2006. Citations: 4.
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Index
albedo, 7
balance heuristics, 11, 19, 67 barycentric coordinates, 37 bi-directional path tracing, 65
Bidirectional Reflectance Distribution Function, 6 BIH, 40
bounding interval hierarchy, 40 bounding volume hierarchy, 40 BRDF, 6
BVH, 40 clustered, 80
combined sample distribution, 11 compact representation, 41 conical-directional reflectance, 7 control variates, 25
Correlated sampling, 25
decomposition and importance sampling, 17 dependent sampling, 72
differential radiant power, 8
directional-hemispherical reflectance, 7 discontinuity buffer, 65
entry points, 75 fragmentation, 41 gathering walks, 8
generalized shadowing surface area, 48 importance sampling, 10
instant radiosity, 12, 65 inverse scattering density, 7 irradiance caching, 65 items, 75
IVM, 38 joining, 70 leaf list, 42
light path map, 75, 77 light paths, 8
light source sampling, 8 LPM, 75, 77
LPM pane, 75 luminance, 20
luminosity function, 20 main part separation, 25
multiple importance sampling, 11, 17, 18, 66, 67
next event estimation, 9 node texture, 42
PCA, 80 photon hit, 12 photon map, 65
point-to-polygon form-factor, 29 principal component analysis, 80 randomized reflected radiance, 12 ray casting, 6
ray shooting, 6
recursive ray tracing, 6 reference points, 75 root mean square, 4
sample importance resampling, 86 scattering density, 8
shooting walks, 8 splitting, 70 surface area, 46
teapot in the stadium, 40 unified shader architecture, 63 virtual light sources, 14, 65 virtual light sources method, 5 virtual point lights, 14
visibility factor, 8 weighted combination, 17
97
Nomenclature
α(f) weight of light paths from framef
αi(u) weighting functions of multiple importance sampling
Γ visibility masked geometric factor Λ number of representative wavelengths λ wavelength index; combination weight
~z(fi ) theith node of a light path from frame f
~zi theith node of a light path s shooting path
u point in multidimensional space
W(λ)i combined scattering density of sampling tech-niqueiat wavelength λ
y vector of light samples z light path
L domain of light surface points U multidimensional integral domain Z domain of light paths
dΦ differential radiant power
dΦvpl differential radiant power arrving at a vir-tual point light
ν(~x, ω) environment visibility
ν(~x, ~y) point to point visibility factor Ω domain of directions
ω direction
ΩP solid angle of measurement Φ radiant power
Φe emitted radiant power Pr{·} probability
θ outgoing light angle θ0 incoming light angle
˜
a average albedo
~b barycentric coordinate vector
~b? barycentric coordinates of intersection
~c sphere center d~ ray direction
~e eye position
~n plane normal
~o ray origin
~q plane parameter vector
~q)† geometric inverse of the plane parameter vector with respect to the unit sphere
~vi position vector of theith vertex of a triangle
~x shaded point
~x? intersection point
~y light sample point
ξ geometric attenuation factor
a albedo
d distance D2[·] variance E[·] expected value f frame index
fr bidirectional reflection distribution function (BRDF)
G geometric factor g(u) main part function
h(~x, ω) directional visibility function
H(λ) luminosity weight of representative wave-lengthλ
L radiance
l length of a gathering path Le emitted radiance
Lrd radiance reflected due to direct illumination Lri radiance reflected due to indirect
illumina-tion
98