|Closes the session that began with an opening call to Open_Face(). More...|
|void||Open_Face (int offset)|
|Prepares a face within a shell or mesh for the local overriding of drawing attributes. More...|
Prepares a face within a shell or mesh for the local overriding of drawing attributes.
id - The face number that identifies the face. The first face is zero.
Open_Face() is analogous to Open_Segment() and makes a particular face within a shell, mesh, or polycylinder ready for further work. The shell or mesh itself must already have been opened with a call to Open_Geometry() .
Once the face is open you can do the following:
- Set, Show, or UnSet the face color using any of the many color routines.
- Set, Show, or UnSet the face pattern.
- Set, Show, or UnSet the face visibility.
- Set, Show, or UnSet a local face normal.
These attributes override the normal segment-wide setting of the attribute and cause the face in question to be drawn differently. The settings have no effect at all on how the edges or vertices associated with the face are to be drawn.
If "color interpolating" is in effect (see Set_Rendering_Options() ) and one or more vertices have a face color set, that vertex face color will take precedence over the general face color set during an Open_Face().
Your program should make sure that there is eventually a Close_Face() to match every Open.
If the open geometry is a shell, the identifier is the relative position in the "face list" originally passed to Insert_Shell().
If you are working on a mesh, please refer to Insert_Mesh() for guidance on the face numbering.
If the open geometry is a polycylinder, "face 0" refers to the starting endcap; "face 1" refers to the ending endcap.
As of this writing polycylinders do not, at least not yet, accept face colors. Polycylinder faces currently only accept face normals (to get the caps to align flush with other geometry).