点到直线的垂足算法.doc

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1、点到直线的垂足算法//二维空间点到直线的垂足structPoint{　　doublex,y;}PointGetFootOfPerpendicular(constPoint&pt,//直线外一点constPoint&begin,//直线开始点constPoint&end)//直线结束点{PointretVal;doubledx=begin.x-end.x;doubledy=begin.y-end.y;if(abs(dx)<0.00000001&&abs(dy)<0.00000001){retVal=begin;returnretVa

2、l;}doubleu=(pt.x-begin.x)*(begin.x-end.x)+(pt.y-begin.y)*(begin.y-end.y);u=u/((dx*dx)+(dy*dy));retVal.x=begin.x+u*dx;retVal.y=begin.y+u*dy;returnretVal;}//三维空间点到直线的垂足structPoint{　　doublex,y,z;}PointGetFootOfPerpendicular(constPoint&pt,//直线外一点constPoint&begin,//直线开始点co

3、nstPoint&end)//直线结束点{PointretVal;doubledx=begin.x-end.x;doubledy=begin.y-end.y;　　doubledz=begin.z-end.z;if(abs(dx)<0.00000001&&abs(dy)<0.00000001&&abs(dz)<0.00000001){retVal=begin;returnretVal;}doubleu=(pt.x-begin.x)*(begin.x-end.x)+(pt.y-begin.y)*(begin.y-end.y)+(pt.

4、z-begin.z)*(begin.z-end.z);u=u/((dx*dx)+(dy*dy)+(dz*dz));retVal.x=begin.x+u*dx;retVal.y=begin.y+u*dy;　　retVal.y=begin.z+u*dz;　　returnretVal;}