class Camera { 
  float distance;
  float dEcranOeil;
  float dEcranRepere;
  Vecteur oeil,PosRegard,vectEyePosRegard;
  Vecteur camX,camY,camZ,camX0,camY0,camZ0,vectEyeMouse,vectEyeImpact,vectOrigineImpact ;
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++ 
  public Camera(){
    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=5000;
    vectOrigineImpact=new Vecteur();
    PosRegard=new Vecteur(500,100,600);//
    vectEyePosRegard=camZ.mul(distance);//-------signe
    oeil=PosRegard.ajouter( vectEyePosRegard,-1); 
    dEcranOeil=height/(2*tan(PI/6)); 
    dEcranRepere=distance-dEcranOeil;
     vectEyeImpact=new Vecteur(0,0,-400);
  }
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  void placercamera(){
    oeil=PosRegard.ajouter(camZ,distance); //Posregard ne change pas, ni la distance. Les nouveaux vecteurs camX,camY,camZ sont modifiés par tournerRepere
    camera(oeil.x,oeil.y,oeil.z,PosRegard.x,PosRegard.y,PosRegard.z,camY.x,camY.y,camY.z);
    stroke(0);
      repere(400);//ce repere (en maigre) est le repere absolu
      repereCam(800);//ce repere (en gras)  est dessiné à partir de l'origine absolue mais les vecteurs restent parallèles à l'écran
  }
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++ 
  void tournerCam(Quat lequa){
    camZ=lequa.tourner(camZ0);
    camY=lequa.tourner(camY0);
    camX=lequa.tourner(camX0);
  }
  //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++ 
 public void intersectionRayonRectangle(Rectangle rrr){
    float lambda;
    vectEyeMouse=camZ.mul(-dEcranOeil).ajouter(camY,mouseY-height/2).ajouter(camX,mouseX-width/2); 
    Vecteur EK=rrr.centre.ajouter(oeil,-1.0);
    lambda=EK.dot(rrr.normale)/vectEyeMouse.dot(rrr.normale);
    vectEyeImpact=vectEyeMouse.mul(lambda);
    vectOrigineImpact=oeil.ajouter( vectEyeImpact,1.0);
  } 
    //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++ 
  
  
 public boolean intersectRayonRectangle(Rectangle rrr){
    float lambda;
    vectEyeMouse=camZ.mul(-dEcranOeil).ajouter(camY,mouseY-height/2).ajouter(camX,mouseX-width/2); 
    Vecteur EK=rrr.centre.ajouter(cam.oeil,-1.0);
    lambda=EK.dot(rrr.normale)/vectEyeMouse.dot(rrr.normale);
    vectEyeImpact=vectEyeMouse.mul(lambda);
    vectOrigineImpact=oeil.ajouter( vectEyeImpact,1.0);
    return rrr. impactDansLeRectangle( vectOrigineImpact);
  } 
   //++++++++++++++++++++++++++++++++++++++++++++++++++
  //
  //++++++++++++++++++++++++++++++++++++++++++++++++++ 
 public float  intersectionDragueRectangle(Vecteur rcentre,Vecteur nnormale,Vecteur u1){
      Vecteur rnormale=nnormale.cross(u1).normalize();
    Vecteur vectEyeMouse0=camZ.mul(-dEcranOeil).ajouter(camY,mouseY-height/2).ajouter(camX,mouseX-width/2); 
    Vecteur EK=rcentre.ajouter(cam.oeil,-1.0);
     float lambda0=EK.dot(rnormale)/vectEyeMouse0.dot(rnormale);  
   return ( (vectEyeMouse0.mul(lambda0)).ajouter(EK,-1.0)).dot(nnormale);
  } 
  //++++++++++++++++++++++++++++++++++++++++++++++++++
//
//++++++++++++++++++++++++++++++++++++++++++++++++++
    public  void repere(float lon){
	   stroke(255,0,0);
	   line(0,0,0,lon,0,0);
	   stroke(0,255,0);    
	  line(0,0,0,0,lon,0);
	    stroke(0,0,255);   
	    line(0,0,0,0,0,lon);          
       } 
  //++++++++++++++++++++++++++++++++++++++++++++++++++
//
//++++++++++++++++++++++++++++++++++++++++++++++++++

    public  void repereCam(float lon){
       strokeWeight(3);
	   stroke(255,0,0);
	   line(0,0,0,lon*camX.x,lon*camX.y,lon*camX.z);
	   stroke(0,255,0);    
	  line(0,0,0,lon*camY.x,lon*camY.y,lon*camY.z);
	    stroke(0,0,255);   
	    line(0,0,0,lon*camZ.x,lon*camZ.y,lon*camZ.z);        
   strokeWeight(1);
       }               
}