OpenGL+MFC对三维点云的法向量实现可视化

    最近有小伙伴在问，我想显示一个求得的三维点云中的每一个点的法向量的指向，怎么获得这种逼真的三维显示效果呢？当然是OpenGL啦，也是我自己用的比较习惯，所以就花了十几分钟帮助上面提问的小伙伴解决问题，然后也提供给大家一个查看三维点云法向量的工具，稍后我会在我的ＣＳＤＮ的下载频道上传该软件的Ｒｅｌｅａｓｅ版本供大家使用，主要的显示效果是三维点云中的每一个点使用实心球体表示，法向量用一个方向箭头和圆锥体表示，类似于坐标轴的指向。主要用到三个函数，Render3DCylinder（在任意两个三维点间画圆柱体），Render3DSphere（以任意三维点为中心画球体），Render3DCone（在任意两个三维点之间画圆锥体）。

其三个函数的主要代码如下：

/*-----Render3DCylinder()-------------------------------------------------函数功能：在任意两个三维点之间绘制给定半径的圆柱体管道函数参数：m_point1为第一个三维点m_point2为第二个三维点radius为圆柱体半径slices为段数,slices围绕着z轴分片的个数。stacks为递归次数,stacks顺着z轴分片的个数。stacks和slices垂直。slices和stacks设置的越大，占的内存就越多，这里设置slices为15，stacks为1　------------------------------------------------------------------------*/Render3DCylinder(My3DPoint &m_point1,My3DPoint &m_point2,double radius,double slices,double stacks){//计算目标向量GLdouble  dir_x = m_point2.X-m_point1.X;GLdouble  dir_y = m_point2.Y-m_point1.Y;GLdouble  dir_z = m_point2.Z-m_point1.Z;//算出目标向量模GLdouble  bone_length = sqrt( dir_x*dir_x + dir_y*dir_y + dir_z*dir_z );    GLUquadricObj *  quad_obj = NULL;if ( quad_obj == NULL )quad_obj = gluNewQuadric();gluQuadricDrawStyle(quad_obj, GLU_FILL );gluQuadricNormals(quad_obj, GLU_SMOOTH );glPushMatrix();// 平移到起始点glTranslated( m_point1.X, m_point1.Y, m_point1.Z );// 计算长度double  length;length = sqrt( dir_x*dir_x + dir_y*dir_y + dir_z*dir_z );if ( length < 0.0001 ) { dir_x = 0.0; dir_y = 0.0; dir_z = 1.0;  length = 1.0;}dir_x /= length;  dir_y /= length;  dir_z /= length;// 计算起始向量 GLdouble  up_x, up_y, up_z;up_x = 0.0;up_y = 1.0;up_z = 0.0;// 计算向量(dir_x,dir_y,dir_z)与向量(up_x,up_y,up_z)的法向量(side_x ,side_y,side_z)  double  side_x, side_y, side_z;side_x = up_y * dir_z - up_z * dir_y;side_y = up_z * dir_x - up_x * dir_z;side_z = up_x * dir_y - up_y * dir_x;length = sqrt( side_x*side_x + side_y*side_y + side_z*side_z );if ( length < 0.0001 ) {side_x = 1.0; side_y = 0.0; side_z = 0.0;  length = 1.0;}side_x /= length;  side_y /= length;  side_z /= length;up_x = dir_y * side_z - dir_z * side_y;up_y = dir_z * side_x - dir_x * side_z;up_z = dir_x * side_y - dir_y * side_x;// 计算变换矩阵GLdouble  m[16] = { side_x, side_y, side_z, 0.0,up_x,   up_y,   up_z,   0.0,dir_x,  dir_y,  dir_z,  0.0,0.0,    0.0,    0.0,    1.0 };glMultMatrixd( m );// 圆柱体参数GLdouble radius1= radius;// 半径GLdouble slices1 = slices;//段数GLdouble stack1 = stacks;// 递归次数gluCylinder(quad_obj,radius1,radius,bone_length,slices1,stack1); glPopMatrix();gluDeleteQuadric(quad_obj);//销毁二次方程对象，释放内存}

/*-----Render3DCone()-------------------------------------------------函数功能：在任意两个三维点之间绘制给定半径的三维圆锥体函数参数：m_point1为第一个三维点m_point2为第二个三维点radius为圆柱体半径slices为段数,slices围绕着z轴分片的个数。stacks为递归次数,stacks顺着z轴分片的个数。stacks和slices垂直。slices和stacks设置的越大，占的内存就越多，这里设置slices为15，stacks为1　------------------------------------------------------------------------*/Render3DCone(My3DPoint &m_point1,My3DPoint &m_point2,double radius,double slices,double stacks){//计算目标向量GLdouble  dir_x = m_point2.X-m_point1.X;GLdouble  dir_y = m_point2.Y-m_point1.Y;GLdouble  dir_z = m_point2.Z-m_point1.Z;//算出目标向量模GLdouble  bone_length = sqrt( dir_x*dir_x + dir_y*dir_y + dir_z*dir_z );GLUquadricObj *  quad_obj = NULL;if ( quad_obj == NULL )quad_obj = gluNewQuadric();gluQuadricDrawStyle(quad_obj, GLU_FILL );gluQuadricNormals(quad_obj, GLU_SMOOTH );glPushMatrix();// 平移到起始点glTranslated( m_point1.X, m_point1.Y, m_point1.Z );// 计算长度double  length;length = sqrt( dir_x*dir_x + dir_y*dir_y + dir_z*dir_z );if ( length < 0.0001 ) { dir_x = 0.0; dir_y = 0.0; dir_z = 1.0;  length = 1.0;}dir_x /= length;  dir_y /= length;  dir_z /= length;// 计算起始向量 GLdouble  up_x, up_y, up_z;up_x = 0.0;up_y = 1.0;up_z = 0.0;// 计算向量(dir_x,dir_y,dir_z)与向量(up_x,up_y,up_z)的法向量(side_x ,side_y,side_z)  double  side_x, side_y, side_z;side_x = up_y * dir_z - up_z * dir_y;side_y = up_z * dir_x - up_x * dir_z;side_z = up_x * dir_y - up_y * dir_x;length = sqrt( side_x*side_x + side_y*side_y + side_z*side_z );if ( length < 0.0001 ) {side_x = 1.0; side_y = 0.0; side_z = 0.0;  length = 1.0;}side_x /= length;  side_y /= length;  side_z /= length;up_x = dir_y * side_z - dir_z * side_y;up_y = dir_z * side_x - dir_x * side_z;up_z = dir_x * side_y - dir_y * side_x;// 计算变换矩阵GLdouble  m[16] = { side_x, side_y, side_z, 0.0,up_x,   up_y,   up_z,   0.0,dir_x,  dir_y,  dir_z,  0.0,0.0,    0.0,    0.0,    1.0 };glMultMatrixd( m );// 圆柱体参数GLdouble radius1= radius;// 半径GLdouble slices1 = slices;//段数GLdouble stack1 = stacks;// 递归次数gluCylinder(quad_obj,radius1,0.0,bone_length,slices1,stack1); glPopMatrix();gluDeleteQuadric(quad_obj);//销毁二次方程对象，释放内存}

/*-----Render3DSphere()-------------------------------------------------函数功能：在任意点绘制任意半径的球体函数参数：        qiuxin为My3DPoint结构，存储着球心的XYZ的坐标值radius为圆柱体半径slices为段数,slices围绕着z轴分片的个数。stacks为递归次数,stacks顺着z轴分片的个数。stacks和slices垂直。slices和stacks设置的越大，占的内存就越多，这里设置slices为15，stacks为1　------------------------------------------------------------------------*/Render3DSphere(My3DPoint &qiuxin,double radius,double slices,double stacks){GLUquadricObj *  quad_obj = NULL;if ( quad_obj == NULL )quad_obj = gluNewQuadric();gluQuadricDrawStyle(quad_obj, GLU_FILL );gluQuadricNormals(quad_obj, GLU_SMOOTH );glPushMatrix();// 平移到起始点glTranslated( qiuxin.X, qiuxin.Y, qiuxin.Z );gluSphere(quad_obj,radius,slices,stacks);glPopMatrix();gluDeleteQuadric(quad_obj);//销毁二次方程对象，释放内存}

结果图片如下：

　　　整个程序的源码由于项目的关系不能给出，只能给出发布版本，不过主要的核心的功能是利用上述的三个函数实现的。相应的程序的Realease版本的下载地址：[免费]OpenGL+MFC显示三维点云中每一个点的法向量，Release版本-CSDN下载  http://download.csdn.net/download/hw140701/9970732http://download.csdn.net/download/hw140701/9970732