あ１ - プログラム倉庫

import javax.media.j3d.*;
import javax.vecmath.*;

public class model0915 extends Shape3D{

    public model0915(int n){
        super(createGeometry(n));
    }
    
    private static IndexedQuadArray createGeometry(int n){
        Point3f[] vertices = new Point3f[2*n];
        float a = (float)(2.0* Math.PI / n);
        float b = (float) Math.PI / n;
        Matrix3f Ry = new Matrix3f();
        Matrix3f Rz = new Matrix3f();
        
        for(int i=0; i<2*n; i++){
            Point3f p0 = new Point3f(10,0,0);
            Vector3f v0 = new Vector3f(0,0,1);        
            Ry.rotY(b*i);
            Rz.rotZ(a*i);    
            
            Ry.transform(v0);
            p0.add(v0);
            
            Rz.transform(p0);
            
            vertices[i] = p0;
        }
        
        Color3f[] colors = new Color3f[2*n];
        
        for(int i=0; i<2*n; i++){
            colors[i]=new Color3f(1.0f, 0,0);
        }
        
        IndexedQuadArray geometry =
            new IndexedQuadArray(
                    2*n,
                    GeometryArray.COORDINATES | GeometryArray.COLOR_3,
                    4*n);    
        
        geometry.setCoordinates(0, vertices);
        geometry.setColors(0, colors);
        
        int[] coordInds = new int[4*n];
        
        for(int i=0; i<n-1; i++){
            coordInds[4*i]=i;
            coordInds[4*i+1]=i+n;
            coordInds[4*i+2]=i+n+1;
            coordInds[4*i+3]=i+1;
        }
        
        coordInds[4*(n-1)]=(n-1);
        coordInds[4*(n-1)+1]=(n-1)+n;
        coordInds[4*(n-1)+2]=0;
        coordInds[4*(n-1)+3]=(n-1)+1;
        
        geometry.setCoordinateIndices(0, coordInds);
        
        return geometry;
    }

}