ambient occlusion for particles
DESCRIPTION
Ambient Occlusion for Particles. Encode global information in textures for use during rendering. Computes level of obscurances. Results. Movie 1 (show off some data sets) Movie 2 (use with direct lighting and shadows). Precomputation Time and Memory. Bullet. Fireball. Foam. - PowerPoint PPT PresentationTRANSCRIPT
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Ambient Occlusion for Particles
• Encode global information in textures for use during rendering
![Page 2: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/2.jpg)
Computes level of obscurances
![Page 3: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/3.jpg)
Results
• Movie 1 (show off some data sets)
• Movie 2 (use with direct lighting and shadows)
![Page 4: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/4.jpg)
Precomputation Time and Memory
• Using 20 R14K processors on an SGI Origin 3800 (muse.sci.utah.edu). Textures were 16x16 with 49 samples per texel.
955,000
66 min.
233 MB
952,755
261 min.
232 MB
543,088
33 min.
132 MB
7,157,720
12 hours
1,747 MB
Fireball Bullet Foam
![Page 5: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/5.jpg)
Impact on Performance• 10% slower than direct lighting alone.
• However, using only the ambient occlusion values can yield as good as or better performance than direct lighting alone.
Direct lighting
DL with Textures
Textures w/o DL
Fireball 6 16.43 f/s 14.97 f/s 16.75 f/s
Fireball 11 10.55 f/s 9.59 f/s 10.16 f/s
Cylinder 6 13.32 f/s 12.15 f/s 13.37 f/s
Cylinder 22
11.71 f/s 10.94 f/s 11.75 f/s
Bullet 2 28.17 f/s 25.59 f/s 28.79 f/s
Bullet 12 28.76 f/s 25.71 f/s 28.41 f/s
![Page 6: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/6.jpg)
ImagesDirect Lighting
onlyDirect lighting with ambient occlusion
textures
Ambient occlusion textures only
Cylinder 22 Bullet 6 Fireball 11
![Page 7: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/7.jpg)
Impact on Performance• 10% slower than direct lighting alone.
• However, using only the ambient occlusion values can yield as good as or better performance than direct lighting alone.
Direct lighting
DL with Textures
Textures w/o DL
Fireball 6 16.43 f/s 14.97 f/s 16.75 f/s
Fireball 11 10.55 f/s 9.59 f/s 10.16 f/s
Cylinder 6 13.32 f/s 12.15 f/s 13.37 f/s
Cylinder 22
11.71 f/s 10.94 f/s 11.75 f/s
Bullet 2 28.17 f/s 25.59 f/s 28.79 f/s
Bullet 12 28.76 f/s 25.71 f/s 28.41 f/s
![Page 8: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/8.jpg)
Ingredients for Edges
• Image buffer • Depth buffer• Edge detection kernel• Threshold for zero
crossings
-1 -1 -1
-1 8 -1
-1 -1 -1Laplacian kernel
![Page 9: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/9.jpg)
Movies
• Movie 1 (Varying the threshold and changing the view point and field of view)
• Movie 2 (Time varying data)
![Page 10: Ambient Occlusion for Particles](https://reader034.vdocuments.us/reader034/viewer/2022042506/56813557550346895d9cbbc2/html5/thumbnails/10.jpg)
Performance
Without With Slowdown
A 18.00 f/s 17.52 f/s 2.63%
B 2.250 f/s 2.222 f/s 1.25%
C 2.259 f/s 2.225 f/s 1.51%
D 1.185 f/s 1.172 f/s 1.05%
E 2.720 f/s 2.665 f/s 2.02%
A
B C
D E
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Silhouette and Ambient Occlusion Examples