class Camera { 
  float distance;
  float dEcranOeil;
  float dEcranRepere;
  Vecteur oeil,posRegard;
  Vecteur camX,camY,camZ,camX0,camY0,camZ0,vectEyeMouse,vectImpact ;
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++ 
  public Camera(){
    vectImpact=new Vecteur(0,0,-rayon);
    camZ0=new Vecteur(0,0,1);
    camZ=camZ0.cloner();
    camY0=new Vecteur(0,1,0);
    camY=camY0.cloner();
    camX0=new Vecteur(1,0,0);
    camX=camX0.cloner();
    distance=1000;
    this.posRegard =new Vecteur(0,0,0);
    oeil=posRegard.ajouter(camZ0,-distance);
    dEcranOeil=height/(2*tan(PI/6)); 
    dEcranRepere=distance-dEcranOeil;
  }
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  void placercamera(){
    oeil=posRegard.ajouter(camZ,-distance); 
    camera(oeil.x,oeil.y,oeil.z,posRegard.x,posRegard.y,posRegard.z,camY.x,camY.y,camY.z);
  }
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++ 
  void tournerCam(Quat lequa){
    camZ=lequa.tourner(camZ0);
    camY=lequa.tourner(camY0);
    camX=lequa.tourner(camX0);
  }
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  public void intersectionRayonSphere(){
    float lambda;
    vectEyeMouse=camZ.mul(dEcranOeil).ajouter(camY,mouseY-height/2).ajouter(camX,-mouseX+width/2); 
    float a=sq(vectEyeMouse.length());
    float b=-dEcranOeil*cam.distance;
    float c=sq(distance)-rayon*rayon;
    float delta= b*b-a*c;
    if(delta>=0){
      lambda=(-b-sqrt(delta))/a;
      vectImpact=cam.oeil.ajouter(vectEyeMouse,lambda);
    }
    else{
      lambda=-b/a;
      vectImpact=oeil.ajouter(vectEyeMouse,lambda);
    }
  }
}