/*
	Test program for C code from An Introduction to NURBS
	by David F. Rogers. Copyright (C) 2000 David F. Rogers,
	All rights reserved.
	
	Name: trbasis.c
	Purpose: test the rational basis function routine
	Language: C
	Subroutines called: knot.c 
	Book reference: Chapter 4, Ex. 4.1 , Alg. p 296
*/

#include 	<stdio.h>

main()
{
	int i, index;
	int c,npts,nplusc;
	int x[22];
	float t;
	float h[20];
	float r[20];
	float sum;
	float hnew;

	t = 0.;

	printf("Input number of polygon points and order separated by a space npts c ");
	scanf("%d %d",&npts,&c);

	nplusc = npts + c;

	for (i=1; i <= npts; i++){
		h[i] = 1.0;
	}

	printf("If any homogeneous weighting factor is not 1.0, then \n");
	printf("input number index and value separated by a space, i.e., index h[index] \n");
	printf("Enter 0 0 to skip ");
	scanf("%d %f",&index,&hnew);

	if (( index > 0) && (index <= npts)) h[index]=hnew;

	knot(npts,c,x);
		printf("knot vector is \n");
		for (i = 1; i <= nplusc; i++){
			printf(" %d ", x[i]);
		}
		printf("\n");

		printf("Homogeneous weighting vector is \n");
		for (i = 1; i <= npts; i++){
			printf(" %f ", h[i]);
		}
		printf("\n");

	while(( t >= 0.) && (t <= (float)x[nplusc])){
		printf("Input the parameter value t (Control C to end) ");
		scanf("%f", &t);
		printf("The parameter value t is %f\n",t);
		rbasis(c,t,npts,x,h,r);
		printf("Rational basis functions are \n");
		sum = 0;
		for (i = 1; i <= npts; i++){
			sum = sum + r[i];
		}
		for (i = 1; i <= npts; i++){
			printf("%f ", r[i]);
		}
		printf("\n");
		printf("Sum of the Rational Basis functions is %f \n",sum);
	}
}