/*
	Test program for C code from An Introduction to NURBS
	by David F. Rogers. Copyright (C) 2000 David F. Rogers,
	All rights reserved.
	
	Name: tbspline.c
	Purpose: B-spline curve generator for periodic curves Chap3, Sec. 3.7
	Language: C
	Subroutines called: bsplineu.c
	Book reference:  Chapter 3
*/
	main(){

	int i;
	int npts,k,p1;

	float b[34];  /* allows for up to 11  control vertices */
	float p[103];  /* allows for up to 100 points on curve */

	npts = 11;
	k = 4;     /* fourth order */
	p1 = 21;   /* eleven points on curve */

	for (i = 1; i <= 3*npts; i++){
		b[i] = 0.;
	}

	for (i = 1; i <= 3*p1; i++){
		p[i] = 0.;
	}


/*
	Define the control polygon, Ex. 3.7 in the z=1 plane because
    this is three dimensional routine. x=b[1], y=b[2], z=b[3], etc.
	Although this is the Ex. 3.7 control polygon, matrix methods
	are NOT used to generated the curve.
*/
	b[1]=0;
	b[2]=0;
	b[3]=1;
	b[4]=2;
	b[5]=0;
	b[6]=1;
	b[7]=4;
	b[8]=0;
	b[9]=1;
	b[10]=4;
	b[11]=2;
	b[12]=1;
	b[13]=4;
	b[14]=4;
	b[15]=1;
	b[16]=2;
	b[17]=4;
	b[18]=1;
	b[19]=0;
	b[20]=4;
	b[21]=1;
	b[22]=0;
	b[23]=2;
	b[24]=1;
	b[25]=0;
	b[26]=0;
	b[27]=1;
	b[28]=2;
	b[29]=0;
	b[30]=1;
	b[31]=4;
	b[32]=0;
	b[33]=1;

/*	Comment out the above control polygon, change npts to npts = 4
    and uncomment the control polygon below to test Ex. 3.6	on p. 70.
*/

/*
	b[1]=0;
	b[2]=0;
	b[3]=1;
	b[4]=3;
	b[5]=9;
	b[6]=1;
	b[7]=6;
	b[8]=3;
	b[9]=1;
	b[10]=9;
	b[11]=6;
	b[12]=1;
*/
	bsplineu(npts,k,p1,b,p);

	printf("\nPolygon points\n\n");

	for (i = 1; i <= 3*npts; i=i+3){
		printf(" %f %f %f \n",b[i],b[i+1],b[i+2]);
	}

	printf("\nCurve points\n\n");

	for (i = 1; i <= 3*p1; i=i+3){
		printf(" %f %f %f \n",p[i],p[i+1],p[i+2]);
	}
}