//
//  配列ベースのフレームバッファ
//
//　　2000/12/ 2  宍戸　輝光
//

import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;

public class jfm extends java.applet.Applet implements MouseMotionListener {

	private Image img;
	private int x,y,back[],bg[],chr[];
	private MemoryImageSource ms;

	public void start(){

		int i,j,c;

		back=new int[512*512];
		bg=new int[512*512];
		chr=new int[64*64];

		for (i=0;i<512;i++)
			for (j=0;j<512;j++) {

				c=0xff000000+((i/2) << 8)+(j/2);
				bg[j+i*512]=c;

			}

		for (i=0;i<64*64;i++)
			chr[i]=0xff000000;

		for (i=0;i<64;i++)
			for (j=i/2;j<64-i/2;j++) {

				c=0xff000000+(i*4 << 16)+((63-i)*4);
				chr[j+i*64]=c;

				chr[j+(63-i)*64]=c;

			}

		ms=new MemoryImageSource(512,512,back,0,512);
		ms.setAnimated(true);
		ms.setFullBufferUpdates(true);
		img=createImage(ms);
		ms.newPixels();

		addMouseMotionListener(this);

		repaint();

	}

	public void mouseEntered(MouseEvent e) {}
	public void mouseExited(MouseEvent e) {}
	public void mouseDragged(MouseEvent e) {}
	public void mouseMoved(MouseEvent e) {

		x=e.getX();
		y=e.getY();

		repaint();

	}

	public void paint(Graphics g) {

		System.arraycopy(bg,0,back,0,512*512);

		for (int i=0;i<64;i++)
			for (int j=0;j<64;j++)
				if (j+x>=0 && j+x<512 && i+y>=0 && i+y<512 &&
				    chr[j+i*64]!=0xff000000)
					back[j+x+(i+y)*512]=chr[j+i*64];

		ms.newPixels();

		g.drawImage(img,1,1,this);

	}

	public void update(Graphics g){

		paint(g);

	}

}