opengl 绘制实心圆柱体

glu中提供了一个绘制圆柱体的函数：

   void gluCylinder( GLUquadric* quad,
    GLdouble base,
    GLdouble top,
    GLdouble height,
    GLint slices,
    GLint stacks )
使用方法是：

GLUquadric *pObj; 
pObj = gluNewQuadric();

调用gluCylinder函数时，将pObj作为第一个参数传入。
gluDeleteQuadric(pObj);

 

这样子绘制出的圆柱体是空心的：

我根据gluCylinder函数写了个函数，将两边封顶。

 void mySolidCylinder( GLUquadric*   quad,
                      GLdouble base,
                      GLdouble top,
                      GLdouble height,
                      GLint slices,
                      GLint stacks )
 {
     glColor3f(84.0/255, 0.0, 125.0/255.0);
     gluCylinder(quad, base, top, height, slices, stacks);
     //top
     DrawCircleArea(0.0, 0.0, height, top, slices);
     //base
     DrawCircleArea(0.0, 0.0, 0.0, base, slices);
 }

 GLvoid DrawCircleArea(float cx, float cy, float cz, float r, int num_segments)
 {
     GLfloat vertex[4];

     const GLfloat delta_angle = 2.0*M_PI/num_segments;
     glBegin(GL_TRIANGLE_FAN);

     vertex[0] = cx;
     vertex[1] = cy;
     vertex[2] = cz;
     vertex[3] = 1.0;
     glVertex4fv(vertex);

     //draw the vertex on the contour of the circle
     for(int i = 0; i < num_segments ; i++)
     {
         vertex[0] = std::cos(delta_angle*i) * r + cx;
         vertex[1] = std::sin(delta_angle*i) * r + cy;
         vertex[2] = cz;
         vertex[3] = 1.0;
         glVertex4fv(vertex);
     }

     vertex[0] = 1.0 * r + cx;
     vertex[1] = 0.0 * r + cy;
     vertex[2] = cz;
     vertex[3] = 1.0;
     glVertex4fv(vertex);
     glEnd();
 }

 void mySolidCylinder( GLUquadric*   quad,
                      GLdouble base,
                      GLdouble top,
                      GLdouble height,
                      GLint slices,
                      GLint stacks )
 {
     glColor3f(84.0/255, 0.0, 125.0/255.0);
     gluCylinder(quad, base, top, height, slices, stacks);
     //top
     DrawCircleArea(0.0, 0.0, height, top, slices);
     //base
     DrawCircleArea(0.0, 0.0, 0.0, base, slices);
 }

 GLvoid DrawCircleArea(float cx, float cy, float cz, float r, int num_segments)
 {
     GLfloat vertex[4];

     const GLfloat delta_angle = 2.0*M_PI/num_segments;
     glBegin(GL_TRIANGLE_FAN);

     vertex[0] = cx;
     vertex[1] = cy;
     vertex[2] = cz;
     vertex[3] = 1.0;
     glVertex4fv(vertex);

     //draw the vertex on the contour of the circle
     for(int i = 0; i < num_segments ; i++)
     {
         vertex[0] = std::cos(delta_angle*i) * r + cx;
         vertex[1] = std::sin(delta_angle*i) * r + cy;
         vertex[2] = cz;
         vertex[3] = 1.0;
         glVertex4fv(vertex);
     }

     vertex[0] = 1.0 * r + cx;
     vertex[1] = 0.0 * r + cy;
     vertex[2] = cz;
     vertex[3] = 1.0;
     glVertex4fv(vertex);
     glEnd();
 }

最终绘制出的圆柱体：