public class sphere extends Surface{

    double[] center;
    double[] originalCenter;
    double R;
    double[] toCenter;
    static double[] e=new double[] {0,0,1};//simplifying by assuming the eye is infinitely remote

    public sphere(){
	center=new double[] {0,0,-5};
	originalCenter=new double[] {0,0,-5};
	R=0.8;
	m=new material();
    }

    public sphere(double r, material ms, double x, double y, double z){
	center=new double[3];
	originalCenter=new double[3];	
	originalCenter[0]=center[0]=x;
	originalCenter[1]=center[1]=y;
	originalCenter[2]=center[2]=z;
	m = new material();
	m.copy(ms);
	R=r;
    }

    public void setCenter(double[] sr){
	originalCenter[0]=center[0] = sr[0];
	originalCenter[1]=center[1] = sr[1];
	originalCenter[2]=center[2] = sr[2];
    }

    void setTransfo(Matrix3D tfs){//only for transformations that don't change the radius
	tfOrig=new Matrix3D();
	tfOrig.copy(tfs);

	tf=new Matrix3D();
	tf.copy(tfs);    
	double[] tmp=new double[4];
	tmp[0]=originalCenter[0];
	tmp[1]=originalCenter[1];
	tmp[2]=originalCenter[2];
	tmp[3]=1;
	double[] tmp2=new double[4];
	tf.transform(tmp, tmp2);
	center[0]=tmp2[0];
	center[1]=tmp2[1];
	center[2]=tmp2[2];
    }

    double[] intersections(double[]v, double[] w){
	double[] res=new double[2];
	res[0]=res[1]=-1;
	double A=dotP(w,w);
	toCenter=diff(v,center);
	double B=2*dotP(toCenter,w);
	double C=dotP(toCenter,toCenter) - R*R;
	double discr=B*B-4*A*C;
	if (discr==0) res[0]=res[1]=-B/(2*A);
	if (discr>0){
	    res[0]= (-B-Math.sqrt(discr))/(2*A);
	    res[1]= (-B+Math.sqrt(discr))/(2*A);
	}	
	Vector thisV=new Vector(v);
	Vector thisW=new Vector(w);
	currentNormalIn=thisV.add(thisW.scalMult(res[0]));
	currentNormalIn=currentNormalIn.diff(center);
	currentNormalIn.normalize();
	currentNormalOut=thisV.add(thisW.scalMult(res[1]));
	currentNormalOut=currentNormalOut.diff(center);
	currentNormalOut.normalize();
	return res;
    }

    Vector getNormal(double[] currPt){
	double[] normV=diff(currPt, center);
	normV=normalize(normV);
	Vector res=new Vector(normV);	
	return res;
    }

    public double intersect(double[] v, double[] w){
	double A=dotP(w,w);
	toCenter=diff(v,center);
	double B=2*dotP(toCenter,w);
	double C=dotP(toCenter,toCenter) - R*R;
	double discr=B*B-4*A*C;
	if (discr<0) return 10500;
	if (discr==0) return -B/(2*A);
	if (discr>0) return (-B-Math.sqrt(discr))/(2*A);
		
	return 10500;
    }

    public double intersect2(double[] v, double[] w){
	double A=dotP(w,w);
	toCenter=diff(v,center);
	double B=2*dotP(toCenter,w);
	double C=dotP(toCenter,toCenter) - R*R;
	double discr=B*B-4*A*C;
	if (discr<0) return 10500;
	if (discr==0) return -B/(2*A);
	//if (discr>0) return (-B-Math.sqrt(discr))/(2*A);
	
	if (discr>0){
	    double root1=(-B-Math.sqrt(discr))/(2*A);
	    if (root1>=0) return root1;
	    else return (-B+Math.sqrt(discr))/(2*A);
	}
		
	return 10500;
    }


    public double[] shade(light[] lights, double[] v, double[] w, double t){

	double[] res = new double[] {0,0,0};
	double[] currPt=new double[3];
	for (int i=0; i<3; ++i){
	    currPt[i]=v[i]+t*w[i];
	    res[i]=m.ambient[i];
	}
	double[] normV=diff(currPt, center);
	normV=normalize(normV);	
	if (lights!=null){
	    for (int i=0; i<lights.length;i++){
		for (int j=0;j<3;j++){
		    //double vald=lights[i].dir[0]*normV[0]+lights[i].dir[1]*normV[1]+lights[i].dir[2]*normV[2];	
		    double vald=dotP(lights[i].dir, normV);
		    if (vald>0)
			res[j]+=lights[i].rgb[j]*m.diffuse[j]*vald;// diffuse


		    double[] tmp=new double[3];
		    for (int k=0; k<3; ++k)
			tmp[k]=2*vald*normV[k];

		    double vals=dotP(diff(tmp,lights[i].dir),e);
		    if (vals>0)
			res[j]+=lights[i].rgb[j]*m.specular[j]*Math.pow(vals,m.p);

		}


	    }
	}
	return res;
    }



    public double[] shade(sphere[] obj, light[] lights, double[] v, double[] w, double t){
	double[] res = new double[] {0,0,0};
	double[] currPt=new double[3];
	for (int i=0; i<3; ++i){
	    currPt[i]=v[i]+t*w[i];
	    res[i]=m.ambient[i];
	}
	double[] normV=diff(currPt, center);
	
	normV=normalize(normV);	
	if (lights!=null){
	    for (int i=0; i<lights.length;i++){
		int shadowed=0;
		double[] newSource = new double[3];
		double[] toLight=new double[3];			    
		for (int jj=0; jj<3; jj++) {
		    toLight[jj]=lights[i].dir[jj];			
		    newSource[jj]=currPt[jj]+0.01*toLight[jj];
		    
		}	
		toLight=normalize(toLight);
		for (int ii=0; ii<obj.length; ii++){
		    double tTmp=obj[ii].intersect(newSource,toLight);
		    if (tTmp>0 & tTmp<9995){
			shadowed=1;
			break;			
		    }
		}
		if (shadowed==1){
		    continue;
		}
		
		for (int j=0;j<3;j++){
		    //double vald=lights[i].dir[0]*normV[0]+lights[i].dir[1]*normV[1]+lights[i].dir[2]*normV[2];	
		  
		    double vald=dotP(lights[i].dir, normV);
		    if (vald>0)
			res[j]+=lights[i].rgb[j]*m.diffuse[j]*vald;// diffuse
					

		    double[] tmp=new double[3];
		    for (int k=0; k<3; ++k)
			tmp[k]=2*vald*normV[k];

		    double vals=dotP(diff(tmp,lights[i].dir),e);
		    if (vals>0)
			res[j]+=lights[i].rgb[j]*m.specular[j]*Math.pow(vals,m.p);

				    
		}


	    }
	}
	return res;
    }



    public double dotP(double[] vs, double[] ws){
	double res=0;
	int n=vs.length;
	for (int i=0; i<n; ++i){
	    res+=vs[i]*ws[i];
	}
	return res;
    }

    double[] minus(double[] vs){
	double res[]=new double[3];
	for (int i=0; i<3; ++i){
	    res[i]=-vs[i];
	}
	return res;
    }	

    double[] scalMult(double[] vs, double k){
	double res[]=new double[3];
	for (int i=0; i<3; ++i){
	    res[i]=k*vs[i];
	}
	return res;
    }	

    public double[] diff(double[] vs, double[] ws){
	int n=vs.length;
	double res[]=new double[n];
	for (int i=0; i<n; ++i){
	    res[i]=vs[i]-ws[i];
	}
	return res;
    }	
    public double[] add(double[] vs, double[] ws){
	int n=vs.length;
	double res[]=new double[n];
	for (int i=0; i<n; ++i){
	    res[i]=vs[i]+ws[i];
	}
	return res;
    }	

    public double[] normalize(double[] vs){
	int n=vs.length;
	double norm=0;
	for (int i=0; i<n; ++i){
	    norm+=vs[i]*vs[i];
	}
	double[] res=new double[n];
	if(norm!=0)
	    for (int i=0; i<n; ++i){
		res[i]=vs[i]/Math.sqrt(norm);
	    }
	return res;
    }




}