B样条曲线几何原理演示.doc

+ 实验 （二） 项目名称： B样条曲线几何原理演示1、 实验要求在屏幕上使用鼠标左键绘制任意点形成控制多边形，单击鼠标右键绘制三次B样条曲线的程序，同时在控制多边形的每一个控制三角形内显示曲线生成原理，效果如图。原理：2、 实验过程（有关主要代码如下：）bool Flag;/标志CPoint *pt;/顶点int CtrlPoint;/控制多边形顶点/绘制B曲线void CTestView:DrawBSpline()CClientDC dc(this);int i,rate=10;long lx,ly;double F03,F13,F23,F33;lx=ROUND(pt0.x+4.0*pt1.x+pt2.x)/6.0);ly=ROUND(pt0.y+4.0*pt1.y+pt2.y)/6.0);dc.MoveTo(lx,ly);CPen NewPen(PS_SOLID,1,RGB(0,0,255);CPen *OldPen=dc.SelectObject(&NewPen);for(i=1;i=CtrlPoint-3;i+)for(double t=0;t=1;t+=1.0/rate)F03=(-t*t*t+3*t*t-3*t+1)/6;/计算F0,3(t)F13=(3*t*t*t-6*t*t+4)/6;/计算F1,3(t)F23=(-3*t*t*t+3*t*t+3*t+1)/6;/计算F2,3(t)F33=t*t*t/6;/计算B3,3(t)lx=ROUND(pti-1.x*F03+pti.x*F13+pti+1.x*F23+pti+2.x*F33);ly=ROUND(pti-1.y*F03+pti.y*F13+pti+1.y*F23+pti+2.y*F33);dc.LineTo(lx,ly);Sleep(100);dc.SelectObject(OldPen);NewPen.DeleteObject();/绘制控制多边形void CTestView:DrawCharPolygon()CClientDC dc(this);CPen MyPen,*pOldPen;MyPen.CreatePen(PS_SOLID,3,RGB(0,0,0);pOldPen=dc.SelectObject(&MyPen);for(int i=0;iCtrlPoint;i+)if(i=0)dc.MoveTo(pti);dc.Ellipse(pti.x-2,pti.y-2,pti.x+2,pti.y+2);elsedc.LineTo(pti);dc.Ellipse(pti.x-2,pti.y-2,pti.x+2,pti.y+2);dc.SelectObject(pOldPen);MyPen.DeleteObject();/获得屏幕控制点坐标void CTestView:OnLButtonDown(UINT nFlags, CPoint point) / TODO: Add your message handler code here and/or call defaultCView:OnLButtonDown(nFlags, point);if(Flag)ptCtrlPoint.x=point.x;ptCtrlPoint.y=point.y;if(CtrlPointN_MAX_POINT-1)CtrlPoint+;elseFlag=false;DrawCharPolygon();/调用绘制函数void CTestView:OnRButtonDown(UINT nFlags, CPoint point) / TODO: Add your message handler code here and/or call defaultif(CtrlPoint!=0)Flag=false;DrawBSpline();CView:OnRButtonDown(nFlags, point);/绘制绘制几何生成原理图void CTestView:DrawStruct() CClientDC dc(this);CPen NewPen(PS_DOT,1,RGB(0,0,0);CPen *OldPen=dc.SelectObject(&NewPen);int x,y;for(int i=1;i=CtrlPoint-2;i+)x=(pti-1.x+pti+1.x)/2;y=(pti-1.y+pti+1.y)/2;dc.MoveTo(pti.x,pti.y);dc.LineTo(x,y);dc.MoveTo(pti-1.x,pti-1.y);dc.LineTo(pti+1.x,pti+1.y);dc.SelectObject(OldPen);NewPen.DeleteObject();/绘制曲线菜单函数void CTestView:OnMENUBCurve() / TODO: Add your command handler code hereRedrawWindow();MessageBox(单击左键绘制控制多边形，单击右键绘制曲线,提示,MB_OK);pt=new CPointN_MAX_POINT;Flag=true;CtrlPoint=0;/绘制几何结构菜单函