Lighting

It is not necessary to make specific calculations of normal vectors (as is the case for customized surfaces) for spheres, disks, and cylinders. However, you can use the following commands to tailor the automatic lighting.

Quadric Normals(mode) tells what type of normal should be automatically generated. The argument mode can be None, Flat, or Smooth. Flat makes faceted surfaces. Smooth makes the normals at each vertex be the average of the adjacent polygons.

Quadric Orientation(mode) determines which way the normals point. The argument mode can be Inside or Outside.

Quadric Draw Style(mode) specifies the drawing mode. The argument mode can be Fill, Line, Silhouette, or Point.

JMP uses the values that you set for Quadric Normals, Quadric Orientation, and Quadric Draw Style for subsequently generated cylinders, disks, and spheres.

图 13.13 Draw Styles

注意：Other OpenGL documentation refers to quadric objects. JMP has only one, and always uses it.