NAME

DoBackfaceCullSwitch − Create a primitive attribute object for enabling/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 a primitive object will ignore its backward facing surfaces (i.e., those facing away from the viewer) as an efficiency measure when rendering itself.  The possible values for switchvalue are:

DcOn <DCON>
Backward facing surfaces will be ignored.

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

The geometric normal, either specified explicitly or determined implicitly using the right-hand rule, is used to determine whether a surface is backward facing.  For a primitive object to be backface culled, the object 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. 

DEFAULTS

The default value for DoBackfaceCullSwitch is DcOn <DCON>. 

SEE ALSO

DoBackfaceCullable(3D), DoHiddenSurfSwitch(3D)

September 29, 2021