//SimpleBehavior.java
//該程序用來說明如何寫自己的Behavior
import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.AWTEvent;
import com.sun.j3d.utils.applet.MainFrame; 
import com.sun.j3d.utils.geometry.ColorCube;
import com.sun.j3d.utils.universe.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import java.awt.event.*;
import java.util.Enumeration;

public class SimpleBehavior extends Applet {

    public class MyBehavior extends Behavior{
		// 控制目標對象以及狀態信息
        private TransformGroup targetTG;
        private Transform3D rotation = new Transform3D();
        private double angle = 0.0;

        // 構造函數
        MyBehavior(TransformGroup targetTG){
            this.targetTG = targetTG;
					//獲得控制對象的引用
        }

        
		// initialize 方法
        public void initialize(){
			this.wakeupOn(new WakeupOnAWTEvent(KeyEvent.KEY_PRESSED));
					//設置喚醒條件為有鍵按下
        }

        // processStimulus方法
        public void processStimulus(Enumeration criteria){
           	WakeupCriterion wakeup = null;
			AWTEvent[] event = null;
			// 對獲得的事件進行解析，并作出響應的反應
			wakeup = (WakeupCriterion)criteria.nextElement( );
					// 獲得當前的喚醒條件
			if ( wakeup instanceof WakeupOnAWTEvent )
			{
				event = ((WakeupOnAWTEvent)wakeup).getAWTEvent( );
						// 獲得當前的喚醒事件
				KeyEvent keyevent = (KeyEvent)event[0];
						// 轉化為鍵盤事件
				// 判斷是否為左鍵，并做相應左旋處理
				if(keyevent.getKeyCode()==KeyEvent.VK_LEFT){
					angle-=0.1;
					rotation.rotY(angle);
					targetTG.setTransform(rotation);
				}
				// 判斷是否為右鍵，并做相應右旋處理
				if(keyevent.getKeyCode()==KeyEvent.VK_RIGHT){
					angle+=0.1;
					rotation.rotY(angle);
		            targetTG.setTransform(rotation);
				}
			}
			// 設置下一次的喚醒條件
            this.wakeupOn(new WakeupOnAWTEvent(KeyEvent.KEY_PRESSED));
        }
    } 

    public BranchGroup createSceneGraph() {
		BranchGroup objRoot = new BranchGroup();
				// 創建根分支節點
		// 添加一個可旋轉的節點
		TransformGroup objRotate = new TransformGroup();
		objRotate.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
		objRoot.addChild(objRotate);
		objRotate.addChild(new ColorCube(0.4));
				// 向該節點添加六面體
		// 向場景中添加新的行為對象
		MyBehavior myRotationBehavior = new MyBehavior(objRotate);
				// 設定該行為控制的對象為可旋轉的節點
	    myRotationBehavior.setSchedulingBounds(new BoundingSphere());
				// 設定作用范圍	
//	    objRoot.addChild(myRotationBehavior);
		objRotate.addChild(myRotationBehavior);
				// 將行為對象添加到根結點，即接收激勵的來源
		objRoot.compile();
				// 進行優化
		return objRoot;
    } 

    public SimpleBehavior() {
        setLayout(new BorderLayout());
        Canvas3D canvas3D = new Canvas3D(null);
        add("Center", canvas3D);
        BranchGroup scene = createSceneGraph();
		SimpleUniverse simpleU = new SimpleUniverse(canvas3D);
				// 創建虛擬空間
		simpleU.getViewingPlatform().setNominalViewingTransform();
				//將觀察者向后移動
        simpleU.addBranchGraph(scene);
    } 
    public static void main(String[] args) {
        Frame frame = new MainFrame(new SimpleBehavior(), 256, 256);
    } 

}