fast paint texture aaron hertzmann new york university pierce groover cs 395 – npr thursday,...
TRANSCRIPT
![Page 1: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/1.jpg)
Fast Paint Texture
Aaron HertzmannNew York University
Pierce Groover
CS 395 – NPR
Thursday, January 22, 2004
![Page 2: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/2.jpg)
Overview
• Texture plays important part in visual appearance
• Methods can take a long time• Let’s build faster/easy algorithm to
work with existing programs and hardware
![Page 3: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/3.jpg)
Overview
![Page 4: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/4.jpg)
Other work
• Simulated buildup of material– Cockshott et al. ’92, Curtis et al. 97– Processing time, fluid dynamics
• Fixed texture maps– Bronskill, Litwinowicz, Meier,
Markosian– No paint mixing or building– No consistent lighting on individual
strokes
![Page 5: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/5.jpg)
Implementation - Overview
• Raw color image (brush strokes)• Height field is computed
– Height of the painted surface at each pixel
• Final painting generated by bump-mapping the raw image (Phong shading)
![Page 6: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/6.jpg)
Brush Strokes
• Hertzmann and Perlin 2000– Could be any type of stroke though
• Brush stroke specified by a smooth curve – brush radius – solid color.– texture mapped
• Brush strokes are tesselated as triangle strips
![Page 7: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/7.jpg)
Brush Strokes
Opacity Map
![Page 8: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/8.jpg)
Base Image
• Render a color image– Paint color for each
pixel, without lighting
• Composite every brush stroke in back-to-front order– Use opacity map and
paint color
![Page 9: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/9.jpg)
Height Map
• Per-pixel height of the painted surface.• Initialized to black (zero height)• Height determined by texture map, then…
– First strokes are drawn very dark, later strokes drawn lighter.
– Boundaries between the two appear as height discontinuities
• Note that the height map is not cumulative. – Adding stroke heights difficult to prevent
hidden strokes
![Page 10: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/10.jpg)
Height Map
Texture MapHeight Field
![Page 11: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/11.jpg)
Lighting
• Bump-map original flat image using directional derivatives from height map– Phong shading
• Done!
![Page 12: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/12.jpg)
Results
![Page 13: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/13.jpg)
Results
![Page 14: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/14.jpg)
Results
![Page 15: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/15.jpg)
Results
![Page 16: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/16.jpg)
Future Work
• New types of stroke textures and new lighting functions
• Hardware vertex shaders
• Paint textures have the shiny, static appearance of viscous oil paint – More styles could probably be achieved with
suitable stroke textures, height and opacity textures.
![Page 17: Fast Paint Texture Aaron Hertzmann New York University Pierce Groover CS 395 – NPR Thursday, January 22, 2004](https://reader035.vdocuments.site/reader035/viewer/2022062410/5697bf8c1a28abf838c8b8dc/html5/thumbnails/17.jpg)
Thank You
Questions?