patchbasis Subroutine

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

patchbasis Subroutine

Purpose

Sets the current spline surface basis matrices.

Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

void patchbasis(Int32 uid, Int32 vid)

FORTRAN Syntax

SUBROUTINE PATCHB(uid, vid)
INTEGER*4 uid, vid

Description

The patchbasis subroutine sets the current basis matrices (defined by the defbasis subroutine) for the uid and vid parametric directions of a surface patch. The patch subroutine uses the current u and v bases when it executes.

Parameters

uid	Specifies the basis that defines how the control points determine the shape of the patch in the u direction.
vid	Specifies the basis that defines how the control points determine the shape of the patch in the v direction.

Example

The example C language program patch1.c calls the patchbasis subroutine before calling the patch subroutine to set the basis matrix for drawing the curves that represent each surface patch.

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

Defining a cubic spline basis matrix with the defbasis subroutine.

Drawing a surface patch with the patch subroutine.

Setting the number of curves used to represent a patch with the patchcurves subroutine.

Setting the precision at which curves are drawn with the patchprecision subroutine.

Drawing a rational surface patch with the rpatch subroutine.

AIX Graphics Library Overview, Drawing NURBS Curves and Surfaces, and Drawing Wire Frame Curves and Surface Patches.