Name

PSMCV − Specifies the current modeling clipping volume entry in the PHIGS traversal state list. 

Operating States: PHOP, ∗, STOP, ∗
PHIGS standard function
Creates a structure element

Syntax

PSMCLI (OP, NHALFS, HALFSP)

Argument       Data Type      Access     Description
---------------------------------------------------------------------------
OP             Integer        Read       Operator
NHALFS         Integer        Read       Number of half spaces in the list
HALFSP(4,      Real           Read       List of half spaces
NHALFS)
---------------------------------------------------------------------------

Constants

Defined Argument      Constant      Description
---------------------------------------------------------------------------
OP                    PMCREP        Replace the current modeling clipping
                                    volume with the volume specified by the
                                    structure element.
                      PMCINT        Create a volume that is an intersection
                                    of the current modeling clipping volume
                                    and the volume specified by the
                                    structure element.
---------------------------------------------------------------------------

Description

PSMCV specifies the current modeling clipping volume entry in the PHIGS traversal state list.  Depending on the current edit mode, this function either inserts the new structure element directly after the element indicated by the pointer or replaces the element indicated by the pointer.  The pointer then points to the new set modeling clipping volume element. 

Digital PHIGS computes the value as follows: Digital PHIGS transforms the half spaces of the element (using the composite modeling transformation), and intersects the spaces to form a clipping volume, S.  If the application does not specify any half spaces, Digital PHIGS defines the clipping volume to be all modeling coordinate space.  Digital PHIGS combines S (as specified by the element’s operator) with the current modeling clipping volume to form the new value.  During structure traversal, Digital PHIGS uses this volume to clip subsequent output primitives. 

If Digital PHIGS does not support the specified operator, it ignores the structure element.  If any half space is degenerate, Digital PHIGS ignores the structure element. 

If Digital PHIGS is in immediate mode, it performs this function immediately, but the function does not create a structure element. 

Digital PHIGS Version 3.1 does not support this function.

See Also

PQMCLF
PRMCV
PSMCLI
PSMCV3