import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.behaviors.picking.*;

public class convergingLens extends myShape 
{    
    private float radius=1.0f;
    private float halfOuterLength=0.4f;
    private float oneOverSquRoot2=0.707107f;
    // 8 vertices going anticlockwise round the perimeter
        private Point3f vertex0=new Point3f(radius,0.0f,0.0f);
    private Point3f vertex1=new Point3f(radius*oneOverSquRoot2,radius*oneOverSquRoot2,0.0f);
    private Point3f vertex2=new Point3f(0.0f,radius,0.0f);
    private Point3f vertex3=new Point3f(-radius*oneOverSquRoot2,radius*oneOverSquRoot2,0.0f);
        private Point3f vertex4=new Point3f(-radius,0.0f,0.0f);
    private Point3f vertex5=new Point3f(-radius*oneOverSquRoot2,-radius*oneOverSquRoot2,0.0f);
    private Point3f vertex6=new Point3f(0.0f,-radius,0.0f);
    private Point3f vertex7=new Point3f(radius*oneOverSquRoot2,-radius*oneOverSquRoot2,0.0f);
    // vertex in front
    private Point3f vertex8=new Point3f(0.0f,0.0f,halfOuterLength);
    // vertex behind
    private Point3f vertex9=new Point3f(0.0f,0.0f,-halfOuterLength);
    
    private Point3f[] vertices= 
    {
        // front face going anticlockwise
            vertex8, vertex0, vertex1,  
            vertex8, vertex1, vertex2,
            vertex8, vertex2, vertex3,  
            vertex8, vertex3, vertex4,
            vertex8, vertex4, vertex5,
            vertex8, vertex5, vertex6,
            vertex8, vertex6, vertex7,
            vertex8, vertex7, vertex0,
            // back face
            vertex9, vertex4, vertex3,
            vertex9, vertex3, vertex2,
            vertex9, vertex2, vertex1,
            vertex9, vertex1, vertex0,
            vertex9, vertex0, vertex7,
            vertex9, vertex7, vertex6,
            vertex9, vertex6, vertex5,
            vertex9, vertex5, vertex4
    };

    private Point2f texCoord[]= 
    {
        new Point2f(0.0f, 0.0f),
            new Point2f(1.0f, 0.0f),
        new Point2f(0.5f,((float)Math.sqrt(3.0))/2.0f)
    };
    
    private Color3f colour[]=
        {
            new Color3f(1.0f, 0.0f, 0.0f),
            new Color3f(0.0f, 1.0f, 0.0f),
            new Color3f(0.0f, 0.0f, 1.0f),
            new Color3f(1.0f, 1.0f, 0.0f),
            new Color3f(0.0f, 1.0f, 1.0f),
            new Color3f(1.0f, 0.0f, 1.0f)
        };
    

    public convergingLens() 
    {
            int i;

            TriangleArray tetra=new TriangleArray(vertices.length,TriangleArray.COORDINATES|
                TriangleArray.NORMALS|TriangleArray.TEXTURE_COORDINATE_2|TriangleArray.COLOR_3);
                   
                // set the vertex points                
            tetra.setCoordinates(0,vertices);
        for(i=0;i<vertices.length;i++) 
        {
            tetra.setTextureCoordinate(i,texCoord[i%3]);
        }
        
        // set the colours
        for(i=0;i<vertices.length;i++)
        {
            tetra.setColor(i,colour[i%6]);
        }
         
        // set the normals
            int face;
            Vector3f normal=new Vector3f();
            Vector3f vector1=new Vector3f();
            Vector3f vector2=new Vector3f();
            Point3f [] points=new Point3f[3];
            for(i=0;i<3;i++)points[i]=new Point3f();

            for(face=0;face<vertices.length/3;face++) 
            {
                tetra.getCoordinates(face*3,points);
                vector1.sub(points[1],points[0]);
                vector2.sub(points[2],points[0]);
                normal.cross(vector1,vector2);
                normal.normalize();
                for (i=0;i<3;i++) 
                {
                        tetra.setNormal((face*3+i),normal);
                }
            }
            
            // create the shape
            Appearance thisAppearance=new Appearance();
            this.setGeometry(tetra);
            this.setAppearance(thisAppearance);
    }
    
    public String getName()
    {
        return "converging lens";
    }
    
    public Point3f getTriangleCoordinates(int i)
    {
        return vertices[i];
    }    
    
    public int getNumberTriangles()
    {
        return vertices.length/3;
    }
}