pe_fill_area_set3_wshape(3g) — Subroutines

Name

pe_fill_area_set3_wshape − Defines a 3D fill area set with shape flag primitive.

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

Syntax

void pe_fill_area_set3_wshape (
Pint                      shape_flag,      /∗ (I) Shape flag ∗/
const Ppoint_list_list3 ∗point_list_list /∗ (I) List of the list of
                                                    points in the fill
                                                    area set ∗/
)

Data Structures

typedef struct {
    Pint           num_point_lists;     /∗ number of point lists ∗/
    Ppoint_list3 ∗point_lists;         /∗ list of point lists ∗/
} Ppoint_list_list3;
    typedef struct {
        Pint      num_points;   /∗ number of Ppoint3s in the list ∗/
        Ppoint3 ∗points;       /∗ list of points ∗/
    } Ppoint_list3;
        typedef struct {
            Pfloat    x;    /∗ x coordinate ∗/
            Pfloat    y;    /∗ y coordinate ∗/
            Pfloat    z;    /∗ z coordinate ∗/
        } Ppoint3;

Constants

Defined Argument    Constant             Description
---------------------------------------------------------------------------
shape_flag          PSHAPE_COMPLEX       Some facets are self-intersecting.
                    PSHAPE_NONCONVEX     Some facets are concave, but none
                                         are self-intersecting.
                    PSHAPE_CONVEX        All facets are convex.
                    PSHAPE_UNKNOWN       Unknown whether any facets are
                                         self-intersecting.
---------------------------------------------------------------------------

Description

pe_fill_area_set3_wshape uses a list of points to define a three-dimensional fill area set 3 with shape flag primitive. The shape flag allows Digital PHIGS to use a more efficient fill algorithm for simple polygons.

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 fill area set 3 with shape flag element.

The pe_fill_area_set3_wshape function specifies the three-dimensional form (x, y, and z) of the fill area set 3 with shape flag primitive. The function, along with its attributes, draws a complex polygon. You can specify both the interior and exterior (edge) attributes of the polygon.

A call to this function has the following effects during structure traversal:

•Digital PHIGS generates a set of polygonal areas, made up of a collection of subareas.

•Digital PHIGS closes any unclosed polygon (subarea), implicitly.

•Digital PHIGS binds the current values of the fill area set attributes, as defined in the PHIGS traversal state list, to the fill area set 3 with shape flag primitive.

Attribute values control whether or not edges appear in the display.

The interior of a fill area set 3 with shape flag primitive is defined as follows:

•For a specified point, a straight line is created starting at that point and continuing to infinity.

•If the number of intersections between the straight line and the fill area boundary is odd, the point is within the fill area.

•If the number of intersections between the straight line and the fill area boundary is even, the point is outside of the fill area.

•If the straight line passes through a fill area vertex tangentially, the intersection count is not affected.

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