/* Auteur: Nicolas JANEY         */
/* nicolas.janey@univ-fcomte.fr  */
/* Fevrier 2003                  */
/* Deplacement a travers         */
/* un alignement de tores        */

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/glu.h>

static float z = 700.0F ;
static float dz = 1.0F ;
static int mode = 1;

void myinit(void) {
  glClearColor(0.8F,0.8F,0.8F,1.0F) ;
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_AUTO_NORMAL);
}

void scene(void) {
  glPushMatrix();
  for ( int i = 0 ; i < 10 ; i++ ) {
    glPushMatrix();
    glTranslatef(0.0F,0.0F,50.0F*i) ;
    if ( mode )
      glutSolidTorus(25.0,100.0,18,36);
      else
      glutWireTorus(25.0,100.0,18,36);
    glPopMatrix(); }
  glPopMatrix();
}

void display(void) {
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  gluLookAt(0.0,0.0,z,0.0,0.0,z-1.0F,0.0,1.0,0.0);
  scene();
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
}

void idle(void) {
  z -= dz ;
  if ( z <= 0.0F )
    z = 700.0F ;
  glutPostRedisplay() ;
}

void reshape(int w,int h) {
  float xmin,xmax,ymin,ymax;
  glViewport(0,0,w,h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  if( w <= h) {
    xmin = -2.5F;
    xmax = 2.5F;
    ymin = -2.5F*(double) h/w;
    ymax = 2.5F*(double) h/w; }
    else {
    xmin = -2.5F*(double) w/h;
    xmax = 2.5F*(double) w/h;
    ymax = 2.5F;
    ymin = -2.5F; }
  glFrustum(xmin,xmax,ymin,ymax,3.0F,1000.0F);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void key(unsigned char k,int x,int y) {
  static int anim = 1;
  switch (k) {
    case 0x0D : mode = !mode ;
                glutPostRedisplay();
                break;
    case 43   : dz *= 1.1F;
                glutPostRedisplay();
                break;
    case 45   : dz /= 1.1F;
                glutPostRedisplay();
                break;
    case ' '  : anim = !anim;
                glutIdleFunc((anim) ? idle : NULL);
                break;
    case 0x1B : exit(0); }
}

int main(int argc,char **argv) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(450,250); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Deplacement camera"); 
  myinit(); 
  glutReshapeFunc(reshape);
  glutKeyboardFunc(key);
  glutIdleFunc(idle);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}