Texture Mapping
Uniformly colored or shaded surfaces are still unrealistic
- Real objects have surface features, or texture
One option: use a huge number of polygons with appropriate surface coloring and reflectance characteristics
Or, Use texture images to make our surfaces more life-like
- Scan textures from the world (clouds, wood grain) or paint them yourself
- Store the texture in a 2D image
- Map the image onto the surface by a function which maps (u,v) coordinates of our parametric surface onto (x,y) image coordinates
- When shading a surface point we look up the appropriate pixel from the 2-D image, and use that to affect the final color
Voila! Your favorite picture painted onto a donut.
This technique is called parametric texture mapping