#include "stdafx.h"
#include "Bspline.h"


CBspline::CBspline() {
	/* code */

}

CBspline::CBspline(std::vector<vec>pt) {
	/* code */
	int num = (int)(pt.size());
	m_nPoints = num - 1;

	if (num < 4) {
		m_nNumber = num - 1;
	}
	else {
		m_nNumber = 3;
	}

	m_vControlpoint.resize(num);
	memcpy(&m_vControlpoint[0], &pt[0], num * sizeof(vec));
	m_uData.resize(m_nPoints + m_nNumber + 2);
}

CBspline::~CBspline(void) {
	/* code */
}

void CBspline::execute(void) {
	/* code */
	m_vPtResults.clear();
	getNode();

	std::vector<vec>relevantPoint;
	std::vector<float>relevantU;
	relevantPoint.resize(m_nNumber + 1);//Ïà¹Ø¿ØÖƶ¥µã
	relevantU.resize(2 * m_nNumber);//Ïà¹Ø½ÚµãʸÁ¿

	//Ïà¹Ø¿ØÖƶ¥µã¿½±´
	float u = 0;
	int i = m_nNumber; //m±íʾuÖµËùÔڵĽڵã,Ôò¿ØÖƶ¥µãΪm_controlpoint[i-k]\m_controlpoint[i]
	float a = 0.0f;
	int m = 0;
	int n = 0;
	int num = 0;
	int sz = (int)(m_nNumber);
	for (int j = 0; j < 500; j++) {
		n = 0;
		m = 0;
		u = (float)(1.0f * j / 500);

		if (u > m_uData[i + 1]) {
			i++;
		}

		for (m = i - sz; m <= i; m++) {
			relevantPoint[n] = m_vControlpoint[m];
			n++;
		}

		//Ïà¹Ø½ÚµãʸÁ¿¿½±´
		n = 0;
		for (m = i - sz + 1; m <= i + sz; m++) {
			relevantU[n] = m_uData[m];
			n++;
		}
		//¿ªÊ¼²åÖµ¼Æ
		num = (int)(relevantPoint.size());
		for (n = 1; n < num; n++) {
			for (m = 0; m < num - n; m++) {
				a = relevantU[sz + m] - relevantU[m + n - 1];
				if (fabs(a) < 1e-5) {
					a = 0.0;
				}
				else {
					a = (u - relevantU[m + n - 1]) / a;
				}
				relevantPoint[m] = (1 - a)*relevantPoint[m] + a*relevantPoint[m + 1];
			}
		}
		m_vPtResults.push_back(relevantPoint[0]);
	}
}

void CBspline::getNode(void) {
	/* code */
	int sz = (int)(m_nNumber);
	for (int i = 0; i <= sz; i++) {
		m_uData[i] = 0;
	}

	for (int i = 1; i <= sz + 1; i++) {
		m_uData[i + m_nPoints] = 1;
	}

	hartley();
}

void CBspline::hartley(void) {
	/* code */
	std::vector<float> vLength(m_nPoints);
	std::vector<float> vData;
	vData.push_back(0.0);

	vec fValue;
	int fzNum = (int)(m_nPoints);
	for (int i = 0; i < fzNum; i++) {
		fValue = m_vControlpoint[i + 1] - m_vControlpoint[i];
		vLength[i] = len(fValue);
	}

	float sum = 0.0f;
	float fTemp = 0.0f;
	int num = (int)(vLength.size());
	int szNum = (int)(m_nNumber);
	for (int i = 0; i <= num - szNum; i++) {
		fTemp = 0;
		for (int j = 0; j < szNum; j++) {
			fTemp += vLength[i + j];
		}
		sum += fTemp;
		vData.push_back(fTemp);
	}

	int count = (int)(vData.size());
	for (int i = 1; i < count; i++) {
		vData[i] = vData[i - 1] + vData[i];
		m_uData[i + szNum] = vData[i] / sum;
	}
}