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

#define Z 30.0

double	dist = -50.0;
double	theta = 0.0;

void myKeyboard(unsigned char key, int x, int y)
{
  if (key == 27) exit(0);
}

void myDisplay(void)
{
  int i = 0;
  
  glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glEnable(GL_DEPTH_TEST);
  
  glPushMatrix();
  /*		Move view point		*/
  gluLookAt(0.0, 2.0, dist, 0.0, 2.0, dist+1.0, 0.0, 2.0, 0.0);
  glPushMatrix();                       //red teapot
    glTranslated(1.0, 2.0, 0.0);
    glRotated(theta, 1.0, 1.0, 0.0);
    glColor3d(1.0, 0.0, 0.0);
    glutWireTeapot(1.0);
  glPopMatrix();

  glPushMatrix();                       //red teapot2
    glTranslated(1.0, 2.0, 79.8);
    glRotated(theta, 1.0, 1.0, 00.0);
    glColor3d(1.0, 0.0, 0.0);
    glutWireTeapot(1.0);
  glPopMatrix();

  glPushMatrix();                       //blue teapot
    glTranslated(-1.0, 2.0, 30.0);
    glRotated(theta, 2.0, 3.0, 4.0);
    glColor3d(0.0, 0.0, 1.0);
    glutWireTeapot(1.0);
  glPopMatrix();
  
  glColor3d(1.0, 1.0, 1.0);		// draw floor
  glBegin( GL_LINES );
    for ( i=-100; i< 100; i+=2 ) {
      glVertex3i(  i, 0,-100);
      glVertex3i(  i, 0, 100);
      glVertex3i(-100, 0,  i); 
      glVertex3i( 100, 0,  i); 
    }
  glEnd();

  glPopMatrix();
  glutSwapBuffers(); 
}

void myIdle(void)
{
  dist += 0.5;
  if (dist >= Z ) 
    dist = -50.0;
  theta = fmod(theta + 2, 360.0);
  glutPostRedisplay();
}

void myInit(char *progname)
{
  int width = 640, height = 480;
  
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
  glutInitWindowSize(width, height);
  glutInitWindowPosition(0, 0); 
  glutCreateWindow(progname);
  glClearColor(0.0, 0.0, 0.0, 1.0);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(90.0, (double)width / (double)height, 0.1, 80.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glShadeModel(GL_FLAT);
}

int main(int argc, char** argv)
{
  glutInit(&argc, argv); 
  myInit(argv[0]);
  glutKeyboardFunc(myKeyboard);
  glutIdleFunc(myIdle);
  glutDisplayFunc(myDisplay);
  glutMainLoop(); 
  return 0;
}