import java.applet.Applet;
import java.awt.event.*;
import java.awt.*;


public class ListenTriangle {
    public Complex[] z=new Complex[3];
    public int history;
    
    /** Construct a ListenTriangle where all the vertices are the origin */
    public ListenTriangle() {
        z[0]=new Complex();
        z[1]=new Complex();
        z[2]=new Complex();
    }

    public ListenTriangle(Complex a, Complex b, Complex c) {
        z[0]=new Complex(a);
        z[1]=new Complex(b);
        z[2]=new Complex(c);
    }

    public ListenTriangle(ListenTriangle T) {
        z[0]=new Complex(T.z[0]);
        z[1]=new Complex(T.z[1]);
        z[2]=new Complex(T.z[2]);
    }
    
    /**tells if a point is in the triangle*/
    public int inside(Point p) {
        int i,j,k,G1,G2;
        double x0,x1,x2,y0,y1,y2;
        double test;
        G1=0;
        G2=0;
        
        for(i=0;i<=2;++i) {
            x0=p.x;
            y0=p.y;
            j=i;
            k=i+1;
            if(j>=3) j=j-3;
            if(k>=3) k=k-3;
            x1=z[i].x;
            y1=z[j].y;
            x2=z[k].x;
            y2=z[k].y;
            test=x0*y1+x1*y2+x2*y0-y0*x1-y1*x2-y2*x0;
            if(test>0) G2=1;
            if(test<=0) G2=-1;
            if((G1!=0)&&(G1!=G2)) return(0);
            G1=G2;
        }
        return(1);
    }
    
    
    /**draws the triangle */
    
    public void render(Graphics g,Color C1,Color C2) {
        Polygon P=new Polygon();
        int X1[]={(int)(z[0].x),(int)(z[1].x),(int)(z[2].x)};
        int Y1[]={(int)(z[0].y),(int)(z[1].y),(int)(z[2].y)};
        P.xpoints=X1;
        P.ypoints=Y1;
        P.npoints=3;
        g.setColor(C1);
        g.fillPolygon(P);
        g.setColor(C2);
        g.drawPolygon(P);
    }
}