The document discusses global illumination techniques, including direct illumination, indirect illumination, radiosity, and photon mapping. Radiosity involves subdividing surfaces into patches and calculating light transport between patches. It was introduced in 1984. Photon mapping is a two-pass Monte Carlo method where photons are traced in the first pass to construct a photon map, which is then used in the second pass for rendering. It was introduced in 1995 and uses techniques like Russian roulette. Both radiosity and photon mapping can be used to simulate indirect illumination in games and productions.

1. Global Illumination
:
noerror@hitel.net
: 2005.05.28

2. 1. Global Illumination
Direct Illumination :
Indirect Illumination :
,
2

3. Global Illumination
Technique
Radiosity
Photon Mapping
3

4. Radiosity
, ,
(no specular)
1984 ( )
4

5. Radiosity Process
Surface Substructuring
Scene patch .
Patch
,
.
5

6. Radiosity Process
Li = Lei+ BRDF(j) * Irradiance(Lj)
Li
Lei
BRDF(j) j
Lj j
BRDF : Bidirectional Reflectance Distribution
Function
6

7. Radiosity Process
Multi PASS Rendering
ray
. (1st pass)
. .
7

8. Radiosity
.
.(
patch hemicube
.. )
8 .

9. Photon Mapping
Photon :
,
,
1995
9

10. Photon Mapping
Monte-Carlo Method
, N
2 pass
Photon Map Photon
, Photon Map
10

11. Photon Mapping
Process
1
N Photon
Photon Map
. .
Photon
11

12. Photon Mapping
Process
Rusian Rulette
0.5
50%
50%
100%
(k-d Tree)
12

13. Photon Mapping
Process
2
ray traicing
photon
.
13

14. Global Illumination In Game
,
.
.
.
GI
,
14 .

15. 2. Radiosity
Radiosity
Inhouse
=> & =>
1 Direct Illumination =>
Indirect Illumination
15

16. Radiosity
ASE (vertex face
)
triangle Radiosity
16

17. Radiosity
basis
vector .
basis vector texture U,V
17

18. Radiosity
Direct Illumination
.
Indirect Illumination
18

19. /
http://digibath.com/repository/gi_demo.zip
19

20. Radiosity Using Photon Maps
http://www.cs.utah.edu/~bigler/research/photonmaps/photonmaps_g2.html
Global Illumination
http://atec.utdallas.edu/midori/Handouts/global_illumination.htm
Overview of Photon Mapping
http://www.ypoart.com/tutorials/Photon-Overview.htm
Henrik Wann Jensen (photon mapping)
http://graphics.ucsd.edu/~henrik/
20
Radiosity Texture Generator
http://www.dd.chalmers.se/~f97toed/radiosity/Report.htm