ill paste my proj code.here the cube is acting as the light src.how do u make it constant and make the torous rotate.and plz comment each line.i got this project from the net.i dont know how its working


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

static int spin = 0,n=60;
int x=0,y=0,z=0;
/*  Initialize material property, light source, lighting model,
*  and depth buffer.
*/


void init(void)
{
 glClearColor (0.0, 0.0, 0.0, 0.0);
 //glShadeModel (GL_SMOOTH);
 glEnable(GL_LIGHTING);
 glEnable(GL_LIGHT0);
 glEnable(GL_DEPTH_TEST);
}

/*  Here is where the light position is reset after the modeling
*  transformation (glRotated) is called.  This places the
*  light at a new position in world coordinates.  The cube
*  represents the position of the light.
*/


void display(void)
{

 GLfloat position[] = { 0.0, 0.0, 1.5, 1.0 };
 GLfloat mat_diffuse[]={.0,1.7,.0,1.0};
 glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 glPushMatrix ();
 gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    glColor3f (0.0, 1.0, 1.0);
glPushMatrix ();
glRotated ((GLdouble) spin, x,y,z);
 glLightfv (GL_LIGHT0, GL_POSITION, position);
 glMaterialfv(GL_FRONT,GL_DIFFUSE,mat_diffuse);
 glTranslated (0.0, 0.0, 1.5);
 glDisable (GL_LIGHTING);
 glColor3f (1.0, .0, 0.0);
 glutWireCube (0.1);
 glEnable (GL_LIGHTING);
 glPopMatrix ();

 glutSolidTorus (0.275, 0.85, 8, 15);

 glPopMatrix ();
 glFlush ();
}
void display1(void)
{

 GLfloat position[] = { 0.0, 0.0, 1.5, 1.0 };
 GLfloat mat_diffuse[]={1.0,0.0,.0,1.0};
 glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 glPushMatrix ();
 gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    glColor3f (0.0, 1.0, 1.0);
glPushMatrix ();
glRotated ((GLdouble) spin, x,y,z);
 glLightfv (GL_LIGHT0, GL_POSITION, position);
 glMaterialfv(GL_FRONT,GL_DIFFUSE,mat_diffuse);
 glTranslated (0.0, 0.0, 1.5);
 glDisable (GL_LIGHTING);
 glColor3f (1.0, .0, 0.0);
 glutWireCube (0.1);
 glEnable (GL_LIGHTING);
 glPopMatrix ();

 glutSolidTorus (0.275, 0.85, 8, 15);

 glPopMatrix ();
 glFlush ();
}
void display2(void)
{

 GLfloat position[] = { 0.0, 0.0, 1.5, 1.0 };
 GLfloat mat_diffuse[]={.0,1.7,.0,1.0};
 glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 glPushMatrix ();
 gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    glColor3f (0.0, 1.0, 1.0);
glPushMatrix ();
glRotated ((GLdouble) spin, x,y,z);
 glLightfv (GL_LIGHT0, GL_POSITION, position);
 glMaterialfv(GL_FRONT,GL_DIFFUSE,mat_diffuse);
 glTranslated (0.0, 0.0, 1.5);
 glDisable (GL_LIGHTING);
 glColor3f (1.0, .0, 0.0);
 glutWireCube (0.1);
 glEnable (GL_LIGHTING);
 glPopMatrix ();

 glutSolidTorus (0.275, 1.85, 8, 15);

 glPopMatrix ();
 glFlush ();
}


void reshape (int w, int h)
{
 glViewport (0, 0, (GLsizei) w, (GLsizei) h);
 glMatrixMode (GL_PROJECTION);
 glLoadIdentity();
 gluPerspective(40.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
 glMatrixMode(GL_MODELVIEW);
 glLoadIdentity();
}

void mytimer(int v)
{
 spin = (spin +5) % 360;
 glutTimerFunc(1600/n,mytimer,v);
 glutPostRedisplay();
}



void menu(int id)
 {
     switch(id)
     {
     case 0:x=1,y=0,z=0;
           break;
     case 1:x=0,y=1,z=0;
           break;
     case 2:x=0,y=0,z=1;
           break;
     case 3:x=0,y=0,z=0;
     case 4:glShadeModel (GL_SMOOTH);
           break;
     case 5:glShadeModel (GL_FLAT);
           break;
     case 6:exit(0);
                       break;
    case 7:glutDisplayFunc(display1);
                             break;
    case 8:glutDisplayFunc(display);
                break;
    case 9:glutDisplayFunc(display2);
          break;

   

    }
 }


   
int main(int argc, char** argv)
{
 glutInit(&argc, argv);
 glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 glutInitWindowSize (500, 500);
 glutInitWindowPosition (100, 100);
 glutCreateWindow (argv[0]);
 init ();
 glutDisplayFunc(display);
 glutReshapeFunc(reshape);
 //glutMouseFunc(mouse);
 glutTimerFunc(100,mytimer,n);
 glutCreateMenu(menu);
 glutAddMenuEntry("along x axis",0);
 glutAddMenuEntry("along y axis",1);
 glutAddMenuEntry("along z axis",2);
 glutAddMenuEntry("default",3);
 glutAddMenuEntry("smooth shade model",4);
 glutAddMenuEntry("flat shade model",5);
 glutAddMenuEntry("quit",6);
 glutAddMenuEntry("red",7);
 glutAddMenuEntry("green",8);
    glutAddMenuEntry("size change",9);

 glutAttachMenu(GLUT_RIGHT_BUTTON);
 glutMainLoop();
 return 0;
}

what do u mean by-"You show us C code".this is my code.we use visual studio6.0