/* (C) 2010 by folkert@vanheusden.com
 * released under GPL2
 */
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
import javax.imageio.*;
import javax.swing.*;

class jgof extends JPanel {
	final static int dim = 256;
	final static double cmul = 255.0 / (double)dim;

	public jgof() {
	}

        public void paintComponent(Graphics g) {
                super.paintComponent(g);
	}

	public void drawImage(BufferedImage image, boolean [][][] in) {
		for(int ary=0; ary<dim; ary++) {
			for(int arx=0; arx<dim; arx++) {
				for(int arz=dim-1; arz>=0; arz--) {
					int gray = 1 + (int)((double)arz * cmul);
					int rgb = gray << 8;
					int checkz = arz; // - dim / 2;
					if (checkz < 0)
						checkz += dim;
					if (in[arx][ary][checkz]) {
						image.setRGB(arx, ary, rgb);
						break;
					}
				}
			}
		}
	}

	public void loop(boolean emitPng) throws Exception {
		int it = 0;
		Graphics g = getGraphics();
		Graphics2D g2d = (Graphics2D)g;

		assert g2d != null;

		boolean [][][] prev, cur = new boolean[dim][dim][dim];

		/* init world */
		Random r = new Random();
		for(long nr=0; nr<(((long)dim * (long)dim * (long)dim) / 100L); nr++) {
			int x = r.nextInt(dim);
			int y = r.nextInt(dim);
			int z = r.nextInt(dim);

			cur[x][y][z] = true;
		}
		/* draw initial world */
		BufferedImage image = new BufferedImage(dim, dim, BufferedImage.TYPE_INT_RGB);
		drawImage(image, cur);
		g2d.drawImage((Image)image, 0, 0, null);

		g.setColor(Color.RED);
		g.setFont(new Font("Arial", Font.PLAIN, 10));

		for(;;) {
			prev = cur;
			cur = new boolean[dim][dim][dim];

			for(int arz=0; arz<dim; arz++) {
				int gray = 1 + (int)((double)arz * cmul);
				int rgb = gray << 8;

				g.drawLine(0, arz, 0, arz);

				for(int ary=0; ary<dim; ary++) {
					for(int arx=0; arx<dim; arx++) {
						// count neighbours
						int neighbours = 0;

						for(int envz=-1; envz<=1; envz++) {
							for(int envy=-1; envy<=1; envy++) {
								for(int envx=-1; envx<=1; envx++) {
									int x = arx + envx;
									int y = ary + envy;
									int z = arz + envz;
									if (x < 0)
										x = dim - 1;
									else if (x == dim)
										x = 0;
									if (y < 0)
										y = dim - 1;
									else if (y == dim)
										y = 0;
									if (z < 0)
										z = dim - 1;
									else if (z == dim)
										z = 0;

									neighbours += prev[x][y][z] ? 1 : 0;
								}
							}
						}
						neighbours -= prev[arx][ary][arz] ? 1 : 0;

						if (prev[arx][ary][arz])
						{
							if (neighbours < 2 || neighbours > 3) {
							}
							else {
								cur[arx][ary][arz] = true;
							}
						}
						else if (neighbours == 3) {
							cur[arx][ary][arz] = true;
						}


					} // arx
				} // ary
			} // arz

			image = new BufferedImage(dim, dim, BufferedImage.TYPE_INT_RGB);
			drawImage(image, cur);
			g2d.drawImage((Image)image, 0, 0, null);

			++it;
			g2d.drawString("" + it, 10, 10);

			if (emitPng) {
				File f = new File("output" + String.format("%05d", it) + ".png");
				ImageIO.write(image, "png", f);
			}
		} // endless loop
	}

	public static void main(String [] args) throws Exception {
		GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
		GraphicsDevice gd = ge.getDefaultScreenDevice();
		JFrame f = new JFrame();
		f.setSize(dim, dim);
		GraphicsConfiguration gc = gd.getDefaultConfiguration();

		jgof j = new jgof();

		f.setContentPane(j);
		f.setVisible(true);

		j.loop(args.length > 0);
	}
}