Draw a Wireframe model of sphere in OpenGL. Perform Backface Culling of polygon away from viewer

#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>

GLfloat tdist = 0.0;

enum {FILL, WIRE, BACKFACE};

int rendermode = FILL;

void menu(int selection)
{
  rendermode = selection;
  glutPostRedisplay();
}


/* geometry display list names */
enum {SPHERE = 1,FLOOR, WALLS};

void drawscene(void)
{
GLfloat i;   
    glPushMatrix();

    glTranslatef(10.f, -10.f, -400.f);
    //glRotatef(-10.0, 1.0, 0.0, 0.0);
  glRotatef(30.0, 1.0, 0.0, 0.0);
    glCallList(SPHERE);
    glPopMatrix();

   
}

void redraw(void)
{
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);

  switch(rendermode) {
  case FILL:
    drawscene();
    break;
  case WIRE: /* basic wireframe mode */
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    drawscene();
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    break;
  case BACKFACE: /* use backface culling to clean things up */
    glEnable(GL_CULL_FACE);
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    drawscene();
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    glDisable(GL_CULL_FACE);
    break;
 
  }

   
    glFlush();
}

void key(unsigned char key, int x, int y)
{
    switch (key) {
      case 't':
         if (tdist < 140.0) {
            tdist = (tdist + 0.5);
            glutPostRedisplay();
         }
         break;
      case 'T':
         if (tdist > -50.0) {
            tdist = (tdist - 0.5);
            glutPostRedisplay();
         }
         break;
    case 'e':
        exit(0);
    }
}
main(int argc, char *argv[])
{



    GLfloat *tex;
    static GLfloat lightpos[] = {-50.f, -50.f, -320.f, 1.f};
    static GLfloat sphere_mat[] = {0.0, 1.0, 1.0, 1.0};
  
    GLUquadricObj *sphere;

    glutInit(&argc, argv);
    glutInitWindowSize(700, 700);
    glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_STENCIL);
    (void)glutCreateWindow("Wireframe_Backface");
   
    glutDisplayFunc(redraw);
    glutKeyboardFunc(key);

    glutCreateMenu(menu);
    glutAddMenuEntry("Solid Fill", FILL);
    glutAddMenuEntry("Wireframe", WIRE);
    glutAddMenuEntry("Backface Culling", BACKFACE);
 
    glutAttachMenu(GLUT_RIGHT_BUTTON);


    /* draw a perspective scene */
    glMatrixMode(GL_PROJECTION);
    glFrustum(-100., 100., -100., 100., 320., 640.);
    glMatrixMode(GL_MODELVIEW);

   
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glClearColor(1.0, 0.0, 0.0, 1.0);

  
    glLightfv(GL_LIGHT0, GL_POSITION, lightpos);

   
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

    glNewList(SPHERE, GL_COMPILE);

    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, sphere_mat);
    glutSolidSphere (80, 50, 50);
    glEndList();
 
    glutMainLoop();
    return 0;            
}