Specifying the Mapping Function
2-D parameterization (image texture):
- Some objects have natural parameterizations:
- Sphere: use spherical coordinates, (?,?)=(2?u,?v)
- Cylinder: use cylindrical coordinates (u,?)=(u,2?v)
- Parametric surface (such as B-spline or Bezier): use patch parameters (u,v)
- Parameterization is less obvious for:
- Polygons: need correspondence between triangles
- Implicit surfaces: very hard to parameterize, so try solid texture
3-D parameterization (solid texture):
- Create a 3D texture map: a volume parameterized by (u,v,w)
- Create solid textures from images by projecting the same image to different depths (slide projector effect)