回転

コード
public class Applet3DSakura extends Applet implements Runnable{


	int AppletX = 500;		//アプレットサイズ(x方向)
	int AppletY = 500;		//アプレットサイズ(y方向)

	double Vertex_data[][] = {{-1,  1, 0},	//点P0
							  { 0, -1, 0},	//点P1
							  { 1,  1, 0}	};//点P2
	double Screen_data[][] = new double[3][3];//表示頂点

	int scale = 100;		//描画倍数

	double phi;			//x軸周りの回転角
	double theta;			//y軸周りの回転角

	double rx, ry, rz;		//回転後の頂点座標

	Thread thread;			

	Point point;			//表示したい点の座標


	/*初期メソッド*/
	public void init(){
		setSize(AppletX, AppletY);

		phi = 0;
		theta = 0;

		point = new Point(AppletX / 2, AppletY / 2);
	}



	/*runメソッド呼び出し*/
	public void start(){
		thread = new Thread(this);
		thread.start();
	}



	/*runメソッド*/
	public void run(){
		for(int i = 0; i < 100; i++){
			try{
				Thread.sleep(100);
			}
			catch(InterruptedException e){
			}

			phi += Math.PI / 10;
			//theta += Math.PI / 10;

			setVertexPosition();

			repaint();
		}
	}



	/*頂点の座標を更新するメソッド*/
	public void setVertexPosition(){
		for(int i = 0; i < Vertex_data.length; i++){
           //点を回転させる
			rx = Vertex_data[i][0] * Math.cos(theta) +
					Vertex_data[i][2] * Math.sin(theta);
			ry = Vertex_data[i][0] * Math.sin(phi) * Math.sin(theta) +
					Vertex_data[i][1] * Math.cos(phi) -
						Vertex_data[i][2] * Math.cos(phi) * Math.cos(theta);
			rz = - Vertex_data[i][0] * Math.cos(phi) * Math.sin(theta) +
					Vertex_data[i][1] * Math.sin(phi) +
						Vertex_data[i][2] * Math.cos(phi) * Math.cos(theta);

			Screen_data[i][0] = point.x + (rx * scale);
			Screen_data[i][1] = point.y - (ry * scale);
			Screen_data[i][2] = rz;
		}
	}



	/*描画メソッド*/
	public void paint(Graphics g1){
		Graphics2D g2 = (Graphics2D)g1;
		QuadCurve2D.Double curve1 =
				new QuadCurve2D.Double( Screen_data[0][0], Screen_data[0][1],
										Screen_data[1][0], Screen_data[1][1],
										Screen_data[2][0], Screen_data[2][1]);
		g2.setColor(Color.pink);
		g2.fill(curve1);
	}
}