graphicsanimation.java

java编的模拟一个小球的非弹性碰撞

import java.awt.*;
import java.applet.*;

public class GraphicsAnimation extends Applet implements Runnable
{
	int windowWidth,windowHeight;
	Image offScreenImage;
	Graphics offScreen;
	Thread threadAnimation=null;
	int x,y;
	int xSpeed,ySpeed;
	
	public void init()
	{
		initForm();
		usePageParams();
        initParameters();
	}

	private	final String labelParam = "label";
	private	final String backgroundParam = "background";
	private	final String foregroundParam = "foreground";

	/**
	 * Reads parameters from the applet's HTML host and sets applet
	 * properties.
	 */
	private void usePageParams()
	{
		final String defaultLabel = "Default label";
		final String defaultBackground = "C0C0C0";
		final String defaultForeground = "000000";
		String labelValue;
		String backgroundValue;
		String foregroundValue;

		/** 
		 * Read the <PARAM NAME="label" VALUE="some string">,
		 * <PARAM NAME="background" VALUE="rrggbb">,
		 * and <PARAM NAME="foreground" VALUE="rrggbb"> tags from
		 * the applet's HTML host.
		 */
		labelValue = getParameter(labelParam);
		backgroundValue = getParameter(backgroundParam);
		foregroundValue = getParameter(foregroundParam);

		if ((labelValue == null) || (backgroundValue == null) ||
			(foregroundValue == null))
		{
			/**
			 * There was something wrong with the HTML host tags.
			 * Generate default values.
			 */
			labelValue = defaultLabel;
			backgroundValue = defaultBackground;
			foregroundValue = defaultForeground;
		}

		/**
		 * Set the applet's string label, background color, and
		 * foreground colors.
		 */
		label1.setText(labelValue);
		label1.setBackground(stringToColor(backgroundValue));
		label1.setForeground(stringToColor(foregroundValue));
		this.setBackground(stringToColor(backgroundValue));
		this.setForeground(stringToColor(foregroundValue));
	}

	/**
	 * Converts a string formatted as "rrggbb" to an awt.Color object
	 */
	private Color stringToColor(String paramValue)
	{
		int red;
		int green;
		int blue;

		red = (Integer.decode("0x" + paramValue.substring(0,2))).intValue();
		green = (Integer.decode("0x" + paramValue.substring(2,4))).intValue();
		blue = (Integer.decode("0x" + paramValue.substring(4,6))).intValue();

		return new Color(red,green,blue);
	}

	public String[][] getParameterInfo()
	{
		String[][] info =
		{
			{ labelParam, "String", "Label string to be displayed" },
			{ backgroundParam, "String", "Background color, format \"rrggbb\"" },
			{ foregroundParam, "String", "Foreground color, format \"rrggbb\"" },
		};
		return info;
	}

	Label label1 = new Label();

	void initForm()
	{
		this.setBackground(Color.lightGray);
		this.setForeground(Color.black);
		label1.setText("label1");
		this.setLayout(new BorderLayout());
		this.add("North",label1);
	}
	
	public void initParameters()
	{
		windowWidth=Integer.parseInt(getParameter("width"));
		windowHeight=Integer.parseInt(getParameter("height"));
		offScreenImage=createImage(windowWidth,windowHeight);
		offScreen=offScreenImage.getGraphics();
		draw_groupBox_border(offScreen);
		drawBase(offScreen);
		drawPillar(offScreen,25,31,15,windowHeight-60-60-2);
		drawPillar(offScreen,windowWidth-25-16,31,15,windowHeight-60-40-2);
		x=40;
		y=60;
		xSpeed=9;
		ySpeed=1;
	}
	
	public void paint(Graphics g)
	{
		offScreen.setColor(Color.black);
		offScreen.fillRect(40,31,windowWidth-80,windowHeight-70-32);
		drawSphere(offScreen,x,y,16);
		int h=windowHeight-50-40-1;
		drawGlider(offScreen,x,h,50,20);
		drawPillar(offScreen,25,h,15,20);
		g.drawImage(offScreenImage,0,0,this);
	}
	
	public void draw_groupBox_border(Graphics g)
	{
		BorderRectangle br=new BorderRectangle(24,30,windowWidth-49,windowHeight-60);
		br.setBKColor(Color.black);
		br.draw(g);
	}
	
	public void drawBase(Graphics g)
	{
		int h=windowHeight-50;
		for(int i=0;i<13;i++)drawBrick(g,25+i*50,h,50,20);
		Brick brick_left=new Brick(25,h-20,25,20);
		brick_left.cutLeft(g);
		Brick brick_right=new Brick(650,h-20,25,20);
		brick_right.cutLeft(g);
		
		for(int i=0;i<12;i++)
			drawBrick(g,50+i*50,h-20,50,20);
		g.setColor(Color.lightGray);
		g.drawLine(25,h-21,windowWidth-25,h-21);
	}
	
	public void drawBrick(Graphics g,int x,int y,int w,int h)
	{
		Brick brick=new Brick(x,y,w,h);
		brick.draw(g);
	}
	
	public void drawGlider(Graphics g,int x,int y,int w,int h)
	{
		Brick glider=new Brick(x-12,y,w,h);
		glider.setForeColor(new Color(32,128,255));
		glider.draw(g);
	}
	
	public void drawPillar(Graphics g,int x,int y,int w,int h)
	{
		VirtualCylinder vc=new VirtualCylinder(x,y,w,h);
		vc.draw(g);
	}
	
	public void drawSphere(Graphics g,int x,int y, int radius)
	{
		VirtualSphere vs=new VirtualSphere(x,y,radius);
		vs.draw(g);
	}
	
	public void update(Graphics g)
	{
		paint(g);
	}
	
	public void run()
	{
		while(true)
	    {
			try
			{
				x+=xSpeed;
				if(x>windowWidth-40-16)
				{
					xSpeed=-xSpeed;
					x=windowWidth-40-16;
				}
				else if(x<40)
				{
					xSpeed=-xSpeed;
					x=40;
				}
				y+=ySpeed;
				ySpeed++;
				if(y>windowHeight-90-16)
			    {
					y=2*(windowHeight-90-16)-y;
					ySpeed=-ySpeed+4;
				}
				else if(y<31)
				{
					y=31;
				}
				repaint(40,31,windowWidth-80,windowHeight-70-32);
				Thread.sleep(50);
			}
			catch(InterruptedException e)
			{
				stop();
			}
		}
	}
	
	public void start()
	{
		if(threadAnimation==null)
		{
			threadAnimation=new Thread(this);
			threadAnimation.start();
		}
	}
	
	public void stop()
	{
		if(threadAnimation!=null)
		{
			threadAnimation.stop();
			threadAnimation=null;
		}
	}
	
	public void destroy(){}
}