/*--------------*/
/* Wk21.java    */
/*--------------*/
/*-----------------------*/
/* 円の描画              */
/*-----------------------*/
import java.applet.Applet;
import java.awt.*;                          //BorderLayout,GraphicsConfiguration,event
import javax.media.j3d.*;                   //Java3d
import com.sun.j3d.utils.applet.MainFrame;  //MainFrame
import com.sun.j3d.utils.universe.*;        //SimpleUniverse
import javax.vecmath.*;                     //Point3f,Color3f

public class Wk21 extends Applet{

    private SimpleUniverse simpleU;
    private BoundingSphere bounds = new BoundingSphere(new Point3d(), 10.0);

    public void init(){

        //アプレットの中央にCanvas3Dを追加
        setLayout(new BorderLayout());
        Canvas3D canvas = new Canvas3D(SimpleUniverse.getPreferredConfiguration());
        add(canvas, BorderLayout.CENTER);

        //シーングラフの生成
        simpleU = new SimpleUniverse(canvas);
        simpleU.getViewingPlatform().setNominalViewingTransform();

        //シーングラフの作成
        simpleU.addBranchGraph(createSceneGraph());
    }

    private BranchGroup createSceneGraph(){

        BranchGroup branchG0 = new BranchGroup();

        //背景色の設定（設定が無い場合は黒）
        Background background = new Background(new Color3f(0.3f, 0.3f, 0.3f));
        background.setApplicationBounds(bounds);
        branchG0.addChild(background);

        float r = 0.7f;                        //半径
        int n = 20;                            //分割数
        int[] stripVertexCount = new int[1];
        stripVertexCount[0] = n+1;             //連続する頂点の数を指定

        //線の頂点座標・色設定
        Point3f[] vertex = new Point3f[n+1];
        Color3f[] color = new Color3f[n+1];
        for(int i=0; i<=n; i++){
            vertex[i] = new Point3f(r*(float)Math.cos(2*Math.PI*i/n),
                            r*(float)Math.sin(2*Math.PI*i/n),
                            0.0f);
            color[i] = new Color3f( 1.0f, 1.0f, 0.0f);
        }

        //線の生成
        LineStripArray lineStripA
            = new LineStripArray(vertex.length,
                GeometryArray.COORDINATES | GeometryArray.COLOR_3,
                stripVertexCount);
        lineStripA.setCoordinates(0, vertex);
        lineStripA.setColors(0, color);
        Shape3D lineStrip3D = new Shape3D(lineStripA);
        branchG0.addChild(lineStrip3D);

        branchG0.compile();

        return branchG0;
    }

    public void destroy(){

        simpleU.cleanup();
    }

    public static void main(String[] args){    //Application

        MainFrame frame = new MainFrame(new Wk21(), 512, 512);
    }
}