FILL AREA 3(3P) — SUNPHIGS LIBRARY

NAME

FILL AREA 3 − create a structure element specifying a 3D fill area primitive

SYNOPSIS

C Syntax

void
pfillarea3 ( num_points, points )
Pintnum_points;number of points
Ppoint3∗points;array of points

FORTRAN Syntax

SUBROUTINE pfa3 ( N, PXA, PYA, PZA )
INTEGERNnumber of points
REALPXA(N), PYA(N), PZA(N) coordinates of points (MC)

Required PHIGS Operating States

(PHOP, ∗, STOP, ∗)

DESCRIPTION

Purpose

The FILL AREA 3 function puts a structure element containing the 3D specification of a FILL AREA 3 primitive into the currently open structure. The FILL AREA 3 primitive is a closed polygonal area defined by a series of three dimensional Modelling Coordinate points.

Note: The FILL AREA 3 primitive INTERIOR attributes control the representation of the interior of the area defined by the specified coordinate points. FILL AREA 3 does not have separate edge attributes. See the FILL AREA SET and FILL AREA SET 3 primitives for independent control of the edge properties.

If the current edit mode is INSERT, the structure element created by the FILL AREA 3 subroutine is inserted into the open structure after the element pointed to by the structure’s element pointer. If the edit mode is REPLACE, the FILL AREA 3 element replaces the element pointed to by the element pointer. In either case, the element pointer is updated to point to the new FILL AREA 3 element.

Note: If the workstation is using a Graphics Processor:

1)A GP cannot process fill areas or fill area sets with more than 250 vertices; if a fill area or fill area set is encountered with more than 250 vertices, it will be rendered via software (i.e. not by the GP).

2)There is also a limit on the size of the fill area or fill area set which the GP can process; this limit is a function of the number of bounds in the fill area sets and the total number of vertices. The function is: n_verts ∗ 3 ∗ sizeof(float) + n_bounds ∗ sizeof(short) < 2038 where: n_verts = total number of vertices in the primitive
n_bounds = number of boundaries in the primitive

3)If the application is performing HLHSR using the Z Buffer on the GP and a fill area or fill area set is encountered which cannot be rendered by the GP, it will rendered via software but will not be rendered into the Z Buffer. This will usually result in the image becoming incorrect.

C Input Parameters

num_points
The number of points used to define the FILL AREA 3 primitive. You must specify at least three points; a FILL AREA 3 element that has less than three points will be ignored when the structure is traversed.

pointsA pointer to a list num_points long of Ppoint3 structures containing the x, y, and z coordinates for each point used to define the FILL AREA 3 polygon. The Ppoint3 structure is defined in phigs.h as follows:

typedef struct {
Pfloatx;/∗ x coordinate ∗/
Pfloaty;/∗ y coordinate ∗/
Pfloatz;/∗ z coordinate ∗/
} Ppoint3;

FORTRAN Input Parameters

NThe number of points used to define the FILL AREA 3 polygon. You must specify at least three points; a FILL AREA 3 element that has less than three points will be ignored when the structure is traversed.

PXAAn array of N real values containing the x coordinates of the FILL AREA 3 polygon.

PYAAn array of N real values containing the y coordinates of the FILL AREA 3 polygon.

PZAAn array of N real values containing the z coordinates of the FILL AREA 3 polygon.

Execution

When the structure is traversed, the FILL AREA 3 element will draw a closed polygonal area. The appearance of the interior of the defined area is determined by the attributes listed below. These attributes control the type of fill (SOLID, EMPTY, HOLLOW, HATCH, and PATTERN) and the colour in which the primitive is drawn.

The coordinate points are specified in Modelling Coordinate points. Modelling Coordinate units may be any that are convenient to the application. At traversal, these coordinate values are transformed by the current Local and Global Modelling Transformations, the View Representation selected by the current view index, and the Workstation Transformation current on the workstation to which the structure is posted.

Attributes Applied

The attributes listed below are used to display the FILL AREA 3 primitive when the structure is traversed. The Aspect Source Flags (ASFs) tell where to access the output display attributes. These attributes can come directly from the traversal state list, or they can be accessed indirectly, using the appropriate index in the traversal state list and the corresponding bundled representation in the workstation state list.

interior colourinterior colour index ASF
back interior colourback interior colour ASF
interior styleinterior style ASF
back interior styleback interior style ASF
interior style indexinterior style index ASF
back interior style indexback interior style index ASF
interior shading methodinterior shading method ASF
back interior shading methodback interior shading method ASF
interior reflectance equation interior reflectance equation ASF
back interior reflectance equationback interior reflectance equation ASF
area propertiesarea properties ASF
back area propertiesback area properties ASF
interior index
face distinguishing mode
face culling mode
depth cue index
light source state
name set

ERRORS

005Ignoring function, function requires state (PHOP, ∗, STOP, ∗)

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