图形相交—相切view.cpp

计算机图形学原理及算法教程（VC++版）程序代码

	b=-(l2[0]-l1[0]);
	c1=-l1[0]*l2[1]+l2[0]*l1[1];
	dd=sqrt(a*a+b*b);
	d=-(a*c[0]+b*c[1]+c1)/dd;//计算圆心到直线的有向距离
	
	if(fabs(d)>fabs(c[2])) return -1;  //直线与圆不相交相离
	else if(fabs(d)==fabs(c[2]))   //直线与圆相切
	{
		xa=(b*b*c[0]-a*b*c[1]-a*c1)/(dd*dd);//A点坐标
	ya=-(a*a*c[1]-a*b*c[0]-b*c1)/(dd*dd);
	sa=a/dd;
	ca=-a/dd;
	dp=sqrt(c[2]*c[2]-d*d);
	
	p1[0]=xa-dp*ca;
	p1[1]=ya-dp*sa;
	return 0;
	}
	else if(fabs(d)<fabs(c[2]))
	{xa=(b*b*c[0]-a*b*c[1]-a*c1)/(dd*dd);//A点坐标
	ya=-(a*a*c[1]-a*b*c[0]-b*c1)/(dd*dd);
	sa=a/dd;
	ca=-a/dd;
	dp=sqrt(c[2]*c[2]-d*d);
	
	p1[0]=xa-dp*ca;
	p1[1]=ya-dp*sa;
	p2[0]=xa+dp*ca;
	p2[1]=ya+dp*sa;
	return 1;  //直线与圆相交
	}   

}

/////////////////////////////////////////////////////////////////////////////
// CMyView message handlers

void CMyView::OnLineLine() 
{
	// TODO: Add your command handler code here
	RedrawWindow();
	PushNum=1;
		CDC*pDC=GetDC();	//获得绘图类指针
pDC->TextOut(0,5,"用鼠标右键在窗口取选取四个点,当鼠标右键按下第5次求交点");
ReleaseDC(pDC);	
}

void CMyView::OnLineCiercle1() 
{
	// TODO: Add your command handler code here
	
	PushNum=2;
	Mydraw();
}

void CMyView::OnCircleCircle() 
{
	// TODO: Add your command handler code here
PushNum=4;	
Mydraw();	
}

void CMyView::OnLineCircle() 
{
	// TODO: Add your command handler code here
PushNum=3;
Mydraw();
}

void CMyView::OnRButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
		if(PushNum=1)
	{
	num++;
	if(num<5)
	{	P2[num].x=point.x;			//初始化给相应变量
		P2[num].y=point.y;
	}

	else if(num=5)
	{
	CDC *pDC=GetDC();		//获得CDC对象
	CPen pen1(PS_SOLID,1,(COLORREF)255),pen2(PS_SOLID,1,(COLORREF)255*255);
	CPen* pOldPen=pDC->SelectObject(&pen1);		//设置画线颜色	
	pDC->MoveTo(P2[1].x,P2[1].y);					//在P0点显示小十字光标
	pDC->LineTo(P2[2].x,P2[2].y);
	pDC->MoveTo(P2[3].x,P2[3].y);
	pDC->LineTo(P2[4].x,P2[4].y);
		pDC->SelectObject(pOldPen);
	P1x=P2[1].x;
	P1y=P2[1].y;
	P2x=P2[2].x;
	P2y=P2[2].y;
	P3x=P2[3].x;
	P3y=P2[3].y;
	P4x=P2[4].x;
	P4y=P2[4].y;
	
	int k=PLL(P1x,P1y,P2x,P2y,P3x,P3y,P4x,P4y,Px,Py);		//调用两线段相交子程序
	switch(k)
	{case -1:pDC->TextOut(10,50,"两线段平行或重合!");
	         break;
	 case 0:pDC->TextOut(10,50,"无效交点!");
		     break;
	 case 1:pDC->TextOut(10,50,"您选取的四个点分别为:");
			CString a1,a2;		
			a1.Format("%e	%e      %e  	%e",P1x,P1y,P2x,P2y);	//将数字转化为字符串
			a2.Format("%e	%e      %e  	%e",P3x,P3y,P4x,P4y);
		//	pDC->TextOut(0,40,a);
			a1.Format("%e	%e",P1x,P1y,P2x,P2y);			//将数字转化为字符串
			a2.Format("%e	%e",P3x,P3y,P4x,P4y);			//将数字转化为字符串
					pDC->TextOut(10,70,a1);
					pDC->TextOut(10,90,a1);

		 pDC->TextOut(10,110,"有效交点为:");
			CString b;		
			b.Format("%e	%e",Px,Py);			//将数字转化为字符串
			pDC->TextOut(10,130,b);

			break;
	}
	ReleaseDC(pDC);			//释放CDC对象	
	}
	}
	CView::OnRButtonDown(nFlags, point);
}

void CMyView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags) 
{
	// TODO: Add your message handler code here and/or call default
	if(PushNum==2)
	{
		switch(nChar){			
		case VK_UP:					//上下左右键选择		
			l1[1]-=2;
			Mydraw();
			break;
		case VK_DOWN:
			l1[1]+=2;
			Mydraw();
			break;
		case VK_RIGHT:
			l2[0]+=2;
			Mydraw();
			break;
		case VK_LEFT:
			l2[0]-=2;
			Mydraw();
			break;
		default:
			break;
		}
	}

	if(PushNum==3)
	{
		switch(nChar){			
		case VK_UP:					//上下左右键选择		
			P0[1]-=2;
			Mydraw();
			break;
		case VK_DOWN:
			P0[1]+=2;
			Mydraw();
			break;
		case VK_RIGHT:
			P0[0]+=2;
			Mydraw();
			break;
		case VK_LEFT:
			P0[0]-=2;
			Mydraw();
			break;
		default:
			break;
		}
	}
	if(PushNum==4)
	{
		switch(nChar){			
		case VK_UP:					//上下左右键选择		
			c1[1]-=2;
			Mydraw();
			break;
		case VK_DOWN:
			c1[1]+=2;
			Mydraw();
			break;
		case VK_RIGHT:
			c2[2]+=2;
			Mydraw();
			break;
		case VK_LEFT:
			c2[2]-=2;
			Mydraw();
			break;
		default:
			break;
		}
	}
	CView::OnKeyDown(nChar, nRepCnt, nFlags);
}

void CMyView::OnPlaneCylinder() 
{
	// TODO: Add your command handler code here
	RedrawWindow();
	int i;
	float beta=0.0,db=3.14159/18.0,a;
	float x0=300,y0=200;         //初始化圆柱底圆中心坐标显示位置
	float p1[3],pp1[3],p2[3],pp2[3];  //p1，pp1为椭圆截交线上点变换前后的坐标，p2，pp2为椭圆截交线上点变换前后的坐标，
	float x1,y1,x2,y2;
	float p0[3],R,H,alfa;
	p0[0]=p0[1]=p0[2]=100;
	R=100,H=100,alfa=30;//初始化圆柱与截交面与底面夹角
	a=R*tan(alfa*db*0.1);
	CDC*pDC=GetDC();
	p1[0]=p2[0]=p0[0]+R;//计算底面初始点坐标
	p1[1]=p2[1]=p0[1];
	p1[2]=p0[2]+H+a;
	p2[2]=p0[2];
	
	Tiso(p1,x0,y0,pp1);//正等测变换
	Tiso(p2,x0,y0,pp2);
	x1=pp1[0],y1=pp1[1];
	x2=pp2[0],y2=pp2[2];
	pDC->MoveTo(x1,y1);   //连接z方向竖线
	pDC->LineTo(x2,y2);
	pDC->TextOut(250,80,"平面截圆柱体");
	for(i=1;i<=36;i++)  //按36等分计算和绘制圆柱截交线
	{
	beta+=db;
	p1[0]=p2[0]=p0[0]+R*cos(beta);
	p1[1]=p2[1]=p0[1]+R*sin(beta);
	p1[2]=p0[2]+H+a*(1.0-sin(beta));
	p2[2]=p2[0];
	Tiso(p1,x0,y0,pp1);
	Tiso(p2,x0,y0,pp2);
	CPen pen(PS_SOLID,1,(COLORREF)255);
	CPen* pOldPen=pDC->SelectObject(&pen);		//设置画线颜色	

		
	pDC->MoveTo(x1,y1);   //连接椭圆截交线
	pDC->LineTo(pp1[0],pp1[1]);
	pDC->SelectObject(pOldPen);
    x1=pp1[0],y1=pp1[1];
	x2=pp2[0],y2=pp2[2];
	pDC->MoveTo(x1,y1);   //连接z方向竖线
	pDC->LineTo(x2,y2);
	
	}
	ReleaseDC(pDC);	
}

void CMyView::OnPlaneCone() 
{
RedrawWindow();
	int i;
	float beta=0.0,db=3.14159/18.0,a,r1;
	float x0=300,y0=200;         //初始化圆柱底圆中心坐标显示位置
	float p1[3],pp1[3],p2[3],pp2[3];  //p1，pp1为椭圆截交线上点变换前后的坐标，p2，pp2为椭圆截交线上点变换前后的坐标，
	float x1,y1,x2,y2;
	float p0[3],R,H,alfa,theta;
	p0[0]=p0[1]=p0[2]=100;     //初始化圆锥、截交面与底面夹角
	R=50,H=100,theta=250,alfa=-30;
	r1=R-H*sin(theta*db*0.1);
	a=r1*tan(alfa*db*0.1);
	CDC*pDC=GetDC();
	p1[0]=p0[0]+r1;
	p2[0]=p0[0]+R;//计算底面初始点坐标
	p1[1]=p2[1]=p0[1];
	p1[2]=p0[2]+H+a;
	p2[2]=p0[2];
	
	Tiso(p1,x0,y0,pp1);//正等测变换
	Tiso(p2,x0,y0,pp2);
	x1=pp1[0],y1=pp1[1];
	x2=pp2[0],y2=pp2[2];
	pDC->MoveTo(x1,y1);   //连接z方向竖线
	pDC->LineTo(x2,y2);
	pDC->TextOut(250,60,"平面截圆锥体");
	for(i=1;i<=36;i++)  //按72等分计算和绘制圆柱截交线
	{
	beta+=db;
	p1[0]=p0[0]+r1*cos(beta);
	p2[0]=p0[0]+R*cos(beta);
	p1[1]=p0[1]+r1*sin(beta);
	p2[1]=p0[1]+R*sin(beta);
	p1[2]=p0[2]+H+a*(1.0-sin(beta));
	p2[2]=p0[2];
	Tiso(p1,x0,y0,pp1);
	Tiso(p2,x0,y0,pp2);
	CPen pen(PS_SOLID,1,(COLORREF)255);
	CPen* pOldPen=pDC->SelectObject(&pen);		//设置画线颜色	

	
	pDC->MoveTo(x1,y1);   //连接椭圆截交线
	pDC->LineTo(pp1[0],pp1[1]);
	pDC->SelectObject(pOldPen);
	x1=pp1[0],y1=pp1[1];
	x2=pp2[0],y2=pp2[2];
	pDC->MoveTo(x1,y1);   //连接z方向竖线
	pDC->LineTo(x2,y2);
	
	}	
	ReleaseDC(pDC);
	
}