rpdr Subroutine

GL3.2 for AIX: Graphics Library (GL) Technical Reference

rpdr Subroutine

Purpose

Performs a relative polygon draw.

Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

void rpdr
(Coord dx, Coord dy, Coord dz)

void rpdri
(Icoord dx, Icoord dy, Icoord dz)

void rpdrs
(Scoord dx, Scoord dy, Scoord dz)

void rpdr2
(Coord dx, Coord dy)

void rpdr2i
(Icoord dx, Icoord dy)

void rpdr2s
(Scoord dx, Scoord dy)

FORTRAN Syntax

SUBROUTINE RPDR(dx, dy, dz)
REAL dx, dy, dz

SUBROUTINE RPDRI(dx, dy, dz)
INTEGER*4 dx, dy, dz

SUBROUTINE RPDRS(dx, dy, dz)
INTEGER*2 dx, dy, dz

SUBROUTINE RPDR2(dx, dy)
REAL dx, dy

SUBROUTINE RPDR2I(dx, dy)
INTEGER*4 dx, dy

SUBROUTINE RPDR2S(dx, dy)
INTEGER*2 dx, dy

Note: For FORTRAN users, the INTEGER*2 versions of this subroutine, RPDRS and RPDR2S, should not be called with integer constant parameters. For example, 2 is an integer constant; JJ is an integer variable. The XL FORTRAN compiler, invoked by the xlf command, stores all integer constants as long integers (INTEGER*4), not as short integers (INTEGER*2). Invoking one of the short versions of this subroutine with an integer constant will result in unexpected behavior.

Description

The rpdr subroutine is the relative version of the pdr subroutine. It specifies the next point in a filled polygon, using the previous point (the current graphics position) as the origin.

There can be no more than 256 vertices in a polygon. Therefore, there can be no more than 255 calls to the rpdr subroutine between calls to the rpmv and pclos subroutines.

The rpdr subroutine updates the current graphics position. The next routine starts drawing from that point.

Note: Do not place routines that invalidate the current graphics position within sequences of moves and draws.

The six different forms for the rpdr subroutine are as follows:

	2-D	3-D
Int16	rpdr2s	rpdrs
Int32	rpdr2i	rpdri
float	rpdr2	rpdr

The syntax for each of the subroutine forms is the same except for the parameter type. They differ only in that rpdr expects real coordinates, rpdri expects integer coordinates, and rpdrs expects short integer coordinates. In addition, the rpdr2 routines assume a 2-D point instead of a 3-D point.

Parameters

dx	Specifies the distance from the x coordinate of the current graphics position to the x coordinate of the next corner of the polygon.
dy	Specifies the distance from the y coordinate of the current graphics position to the y coordinate of the next corner of the polygon.
dz	Specifies the distance from the z coordinate of the current graphics position to the z coordinate of the next corner of the polygon.

Implementation Specifics

This subroutine is part of GL in the AIXwindows Environment/6000 Version 1, Release 2 with AIXwindows/3D Feature.

Files

/usr/include/gl/gl.h	Contains C language constant and variable type definitions for GL.
/usr/include/gl/fgl.h	Contains FORTRAN constant and variable type definitions for GL.

Related Information

Allowing the system to draw concave polygons with the concave subroutine.

Closing a filled polygon with the pclos subroutine.

Specifying the next point in a polygon with the pdr subroutine.

Specifying the starting point for a polygon with the pmv subroutine.

Moving the current graphics position to a starting point for a filled polygon relative to the current point with the rpmv subroutine.

Selecting the shading model used to draw a polygon with the shademodel subroutine.

AIX Graphics Library Overview, Drawing with Move-Draw Style Subroutines, and Setting Drawing Attributes.