www.pudn.com > WaveSimulation.rar > Bezier.cpp

// Bezier.cpp: implementation of the CBezier class. 
// 
////////////////////////////////////////////////////////////////////// 
 
#include "stdafx.h" 
#include "Bezier.h" 
 
#include  
#include  
////////////////////////////////////////////////////////////////////// 
// Construction/Destruction 
////////////////////////////////////////////////////////////////////// 
 
CBezier::CBezier() 
{ 
	m_x1 = m_y1 = m_x2 = m_y2 = m_x3 = m_y3 = m_x4 = m_y4 = 0.0f; 
} 
 
CBezier::~CBezier() 
{ 
 
} 
 
void CBezier::Init(float x1,float y1,float x2,float y2, 
					float x3,float y3,float x4,float y4) 
{ 
	m_x1 = x1; 
	m_y1 = y1; 
	m_x2 = x2; 
	m_y2 = y2; 
	m_x3 = x3; 
	m_y3 = y3; 
	m_x4 = x4; 
	m_y4 = y4; 
} 
 
void CBezier::ComputeBezier(float t,float* result) 
{ 
	if(t>1 || t<0) 
	{ 
		result[0] = 1.0f; 
		result[1] = 1.0f; 
	} 
	else 
	{ 
		result[0] = powf( 1-t,3) * m_x1 + powf( 1-t,2) * 3 * t * m_x2 +  
					3 * t * t * (1-t) * m_x3 + powf(t,3) * m_x4; 
		result[1] = powf( 1-t,3) * m_y1 + powf( 1-t,2) * 3 * t * m_y2 +  
					3 * t * t * (1-t) * m_y3 + powf(t,3) * m_y4; 
	} 
} 
 
 
 
void CBezier::DrawBezier() 
{ 
///* 
	glBegin(GL_LINE_STRIP); 
	for(int i = 0; i < 50; i++ ) 
	{ 
		glVertex3fv( (float*)&m_line[i] ); 
	} 
	glEnd(); 
//*/ 
 
	glBegin(GL_LINE_STRIP); 
		glVertex3f(0.0f,m_y1,m_x1); 
		glVertex3f(0.0f,m_y2,m_x2); 
		glVertex3f(0.0f,m_y3,m_x3); 
		glVertex3f(0.0f,m_y4,m_x4); 
	glEnd(); 
} 
 
void CBezier::Result() 
{ 
	for(int i = 0; i < 50; i++) 
	{ 
		float result[2]; 
		ComputeBezier(i / 49.0f,result); 
		m_line[i].x = 0.0f; 
		m_line[i].y = result[1]; 
		m_line[i].z = result[0]; 
	} 
} 
float CBezier::Findy(float z) 
{ 
	static  int preIndex = 0; 
	int tempmarkIndex = preIndex; 
	float result = 0; 
 
	while(tempmarkIndex < 49) 
	{ 
		float prez,nextz; 
		prez = z - m_line[tempmarkIndex].z; 
		nextz = z - m_line[tempmarkIndex + 1].z; 
		int sign = prez * nextz > 0 ? 1 : -1; 
		if(sign == -1)//between there. 
		{ 
			float s = ( z - m_line[tempmarkIndex].z ) / (m_line[tempmarkIndex + 1].z - m_line[tempmarkIndex].z ); 
			result = (1 - s ) * m_line[tempmarkIndex].y + s * m_line[tempmarkIndex  +1].y; 
			return result; 
		} 
		tempmarkIndex++; 
	} 
	//È¡¶ËµãÖµ  
	 
	if(z > m_line[1].z) 
		result = m_line[0].y; 
	if(z < m_line[48].z) 
		result = m_line[49].y; 
 
	return result; 
}