!****h* Main/CubicCrv
! NAME
!   CubicCrv -- Module to produces a cubic curve w/o specifing tangents. 
!   [CubicCrv.MBS]
! DESCRIPTION
!   This module generates all the data required to produce 
!   a bicubic curve from 13 or fewer intersction points.  No tangent 
!   points are provided to this module since they are interpolated inside 
!   the module using a spline curve generated using cur_splarr(). A 'P'
!   array is required to control the 'fullness' of the curve.
!
!   The steps followed are:
!   * Generate a simple spline curve using cur_splarr() using the 13 
!    points input via the CrvPts array.
!   * The 'PValues' and 'CrvPts' arrays must be declared and initialized 
!    prior to calling this function.  The 'PValues' array may be 
!    initialized to a single value using the PValInit() function.  
!    After PValInit() initializes the 'PValues' array 
!    selected points (e.g. at ends) may be set just prior to 
!    calling this function.
!   * Initialize all of arrays except 'CrvPts' and P-Values.
!    P-Values passed to this module must be between 0.0 and 0.85.
!   * Generate tangents vector needed to generate cur_conic curves
!   * A bicubic curve in then formed using cur_conarr().
!
!  SOURCE

GLOBAL GEOMETRY MODULE CubicCrv(
	INT NoPts; 			! Number of curve points
	VAR FLOAT PValues(13);	! 'P' value array
	VAR VECTOR CrvPts(13));	! Points on curve
!***
!
!    Copyright 2006, John J. Hughes
!
!    This source code file is part of the 'NGBproject' files which   
!    execute interactively under the 'VARKON' program, which is   
!    distributed under the terms of the GNU General Public License.
!
!    The 'NGBproject' files are also distributed under the terms of  
!    the GNU GeneralPublic License.  See the GNU General Public License n
!    included ithe file name "COPYING.txt" in the Varkon ./app/NGB/doc 
!    directory for more details.
!
!    NGB is free software; you can redistribute it and/or modify
!    it under the terms of the GNU General Public License as published by
!    the Free Software Foundation; either version 2 of the License, or
!    (at your option) any later version.
!
!    NGB is distributed in the hope that it will be useful,
!    but WITHOUT ANY WARRANTY; without even the implied warranty of
!    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
!    GNU General Public License included in the file name "COPYING.txt".
!
!    You should have received a copy of the GNU General Public License
!    along with NGB; if not, write to the Free Software Foundation, 
!    Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

   INT i;
   VECTOR Tgts(13);
   STRING PStg(13)*1;
   VECTOR MidPts(13);
	
BEGINMODULE

!  ~ Generate a simple spline curve
   cur_splarr(#10,"FERGUSON",NoPts,CrvPts:BLANK=1);

!  ~ Initialize all of arrays except 'CrvPts' and
!  ~ P-Values. P-Values passed to this module must be between 
!  ~ 0.0 and 0.85
   FOR i:=1 TO 13 DO
	PStg(i):="P";
	Tgts(i):=vec(0,0,0);
	MidPts(i):=vec(0,0,0);
   ENDFOR;

!  ~ Generate tangents vector needed to generate cur_conic curves
   FOR i:=1 TO NoPts DO
	Tgts(i):=on(#10,i-0.9); ! Get tangents from the spline curve
   ENDFOR;

!  ~ A bicubic curve can now be formed
   cur_conarr(#20,"FREE",NoPts,CrvPts,Tgts,PStg,Pvalues,MidPts);
   
ENDMODULE