1. Efficient Methods for Ambient Lighting Tamás Umenhoffer Balázs Tóth László Szirmay-Kalos

2. Overview Ambient illumination Illumination model Implementation Results

3. Previous work Obscurances method [Zhukov et al.] Ambient occlusion [Hayden] Spectral obscurances [Mendez et al.] Screen space ao [Mittring]

4. New Illumination Modell Factorization Participating media approximation Substituting the fuzzy measure Local approximation

5. Comparison albedo Classic AO New approximationGI reference Ambient transfer W

6. Containment test Implicit surface f(p)=0 Height field z = h(x, y) Displacement map Z-buffer x z

7. Containment test x Inner parts Outer parts I(p) membership function A B R C

8. Solution Importance sampling –Sample generation (offline) r=1 1. 2.3. –Sampling (online, post processing) T B N N x Depth map

9. Noise reduction Interleaved sampling –Per pixel rotation of the samples Per pixel set of samples Periodical structure –Additional filtering required –Blurry contours 8 samples 8 samples alternating Periodic pattern Sampled neighborhood

10. False silhouette removal Depth difference in the Z buffer –Ambient transfer function fails –Fake shadow on the background object Images without and with silhouette edge elimination

11. Results R=3 R=9 Crytek (260 FPS) Reference Containment test (300 FPS)

12. Results

13. Video

14. Thank you for attention!