/* Auteur: Nicolas JANEY         */
/* nicolas.janey@univ-fcomte.fr  */
/* Avril 2001                    */
/* L'animation en OpenGL         */

#include <stdio.h>

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

static float r1 = 0.0F;
static float r2 = 0.0F;
static float r3 = 0.0F;
static float r4 = 0.0F;
static float blanc[] = { 1.0F,1.0F,1.0F,1.0F };
static float rouge[] = { 1.0F,0.0F,0.0F,1.0F };
static float vert[] = { 0.0F,1.0F,0.0F,1.0F };
static float bleu[] = { 0.0F,0.0F,1.0F,1.0F };

void myinit(void) {
  GLfloat mat_shininess[] = { 50.0 };
  GLfloat light0_position[] = { 1.0,1.0,1.0,0.0 };
  GLfloat light1_position[] = { -1.0,1.0,1.0,0.0 };
  GLfloat light2_position[] = { 1.0,-1.0,1.0,0.0 };
  glMaterialfv(GL_FRONT,GL_SPECULAR,blanc);
  glMaterialfv(GL_FRONT,GL_SHININESS,mat_shininess);
  glLightfv(GL_LIGHT0,GL_DIFFUSE,rouge);
  glLightfv(GL_LIGHT1,GL_DIFFUSE,vert);
  glLightfv(GL_LIGHT2,GL_DIFFUSE,bleu);
  glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
  glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
  glLightfv(GL_LIGHT2,GL_POSITION,light2_position);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_LIGHT1);
  glEnable(GL_LIGHT2);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glEnable(GL_AUTO_NORMAL);
}

void scene(void) {
  glPushMatrix();
  glRotatef(r1,0.0F,1.0F,0.0F);
  glutSolidTorus(0.7,10.0,18,72);
  glRotatef(r2,1.0F,0.0F,0.0F);
  glutSolidTorus(0.7,8.6F,18,72);
  glRotatef(90.0F,0.0F,0.0F,1.0F);
  glRotatef(r3,1.0F,0.0F,0.0F);
  glutSolidTorus(0.7,7.2F,18,72);
  glRotatef(90.0F,0.0F,0.0F,1.0F);
  glRotatef(r4,1.0F,0.0F,0.0F);
  glutSolidTorus(0.7,5.8F,18,72);
  glPopMatrix();
}

void display(void) {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  scene();
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
}

void idle(void) {
  r1 += 0.21137F ;
  r2 += 0.3174F ;
  r3 += 0.4715F ;
  r4 += 0.6433F ;
  glutPostRedisplay() ;
}

void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION) ;
  glLoadIdentity() ;
  glOrtho(-12.0,12.0,(double) -12.0*y/x,(double) 12.0*y/x,-12.0,12.0) ;
  glMatrixMode(GL_MODELVIEW) ;
  glLoadIdentity() ;
}

int main(int argc,char **argv) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(300,300); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Des anneaux en rotation"); 
  myinit();
  glutReshapeFunc(reshape);
  glutIdleFunc(idle);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}