NAME

DoBackfaceCullSwitch − Create a primitive attribute object for enabling or disabling backface culling

SYNOPSIS

C:

DtObject DoBackfaceCullSwitch(switchvalue)
DtSwitch switchvalue;

FORTRAN:

INTEGER∗4 DOBFCS(SWVAL)
INTEGER∗4 SWVAL

DESCRIPTION

DoBackfaceCullSwitch creates a backface cull switch primitive attribute object.  The parameter switchvalue specifies whether subsequent primitive objects will ignore their backward facing surfaces (i.e., those facing away from the viewer) as an efficiency measure when rendering themselves.  The possible values for switchvalue are:

DcOn <DCON>
Backward facing surfaces will be ignored.

DcOff <DCOFF>
Backward facing surfaces will not be ignored.

For a primitive object to be backface culled, it must be backface cullable and the backface cull switch must be enabled.  In general, backface culling should be enabled for any collection of primitive objects consisting of closed surfaces.  The technique used to determine whether a surface is backward facing depends on the renderer and/or device. 

DEFAULTS

The default value for DoBackfaceCullSwitch is DcOn <DCON>. 

SEE ALSO

DoBackfaceCullable(3D), DoHiddenSurfSwitch(3D)

September 02, 1992