Wave

Wave.java

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.util.Random;

import javax.swing.JFrame;


@SuppressWarnings("serial")
public class Wave extends Canvas{

	static int x = 500;
	static int y = 500;

	int blocksize = 1;

	static double damping = 1;//.99;
	static int startStrength = 10;

	static int[][] buffer1 = new int[x][y];
	static int[][] buffer2 = new int[x][y];

	BufferedImage img = null;
	BufferedImage bg = null;

	public static void main(String[] args) throws InterruptedException {
		for(int i=0;i<x;i++){
			for(int j=0;j<y;j++){
				buffer1[i][j] = 0;
				buffer2[i][j] = 0;
			}
		}

		buffer1[x/2][y/2] = startStrength;
		
		JFrame f = new JFrame();
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.setLocation(100, 100);

		Canvas c = new Wave();
		f.add(c);
		f.pack();
		f.setVisible(true);
		c.repaint();

		while(true){
			for(int i=1;i<x-1;i++){
				for(int j=1;j<y-1;j++){
					buffer2[i][j] -= ((
							buffer1[i-1][j] +
							buffer1[i+1][j] +
							buffer1[i][j-1] +
							buffer1[i][j+1]
							) / 2);
					buffer2[i][j] *= -1 * damping;
					//buffer2[i][j] = Math.abs(buffer2[i][j]);
				}
			}
			c.repaint();

			Thread.sleep(50);

			int swap;
			for(int i=0;i<x;i++){
				for(int j=0;j<y;j++){
					swap = buffer2[i][j];
					buffer2[i][j] = buffer1[i][j];
					buffer1[i][j] = swap;
				}
			}
		}
	}

	public Wave() {
		this.setSize(new Dimension(x*blocksize, y*blocksize));
		this.addMouseMotionListener(new MouseAdapter(){
			public void mouseMoved(MouseEvent e) {
				int x = e.getX();
				int y = e.getY();
				buffer1[x][y] = startStrength;
			}
		});
	}

	@Override
	public void update(Graphics g) {
		if(img == null)
			img = new BufferedImage(x*blocksize, y*blocksize, BufferedImage.TYPE_INT_RGB);
		if(bg == null){
			bg = new BufferedImage(x*blocksize, y*blocksize, BufferedImage.TYPE_INT_RGB);
			generate(bg.getGraphics(), bg.getHeight(), bg.getWidth());
		}

		img.getGraphics().clearRect(0, 0, img.getWidth(), img.getHeight());
		paintImg(img.getGraphics());
		paint(g);
	}

	private void generate(Graphics g, int height, int width) {
		int blocksize = 50;
		Random r = new Random();
		for(int i=0;i<x;i++){
			for(int j=0;j<y;j++){
				int red = r.nextInt(255);
				int blue = r.nextInt(255);
				int green = r.nextInt(255);
				Color c = new Color(red, green, blue);
				g.setColor(c);
				g.fillRect(i*blocksize, j*blocksize, blocksize, blocksize);
			}
		}
	}

	@Override
	public void paint(Graphics g) {
		g.drawImage(img, 0, 0, null);
	}


	//	for every pixel (x,y) in the buffer
	//
	//    Xoffset = buffer(x-1, y) - buffer(x+1, y)
	//    Yoffset = buffer(x, y-1) - buffer(x, y+1)
	//
	//    Shading = Xoffset
	//
	//    t = texture(x+Xoffset, y+Yoffset)
	//
	//    p = t + Shading
	//
	//    plot pixel at (x,y) with colour p
	//
	//  end loop

	public void paintImg(Graphics g) {
		for(int i=1;i<x-1;i++){
			for(int j=1;j<y-1;j++){
				int xoffset = buffer2[i-1][j] - buffer2[i+1][j];
				int yoffset = buffer2[i][j-1] - buffer2[i][j+1];
				int s = xoffset * 10;
				int t = bg.getRGB(i + xoffset, j + yoffset);
				//int t = bg.getRGB(i, j);
				int r = t >> 16 & 0xFF;
			int gr = t >> 8 & 0xFF;
			int b = t & 0xFF;;

			r += s;
			if(r > 255) r = 255;
			if(r < 0) r = 0;
			gr += s;
			if(gr > 255) gr = 255;
			if(gr < 0) gr = 0;
			b += s;
			if(b > 255) b = 255;
			if(b < 0) b = 0;


			g.setColor(new Color(r, gr, b));
			g.fillRect(i*blocksize, j*blocksize, blocksize, blocksize);
			/*
				int height = buffer2[i][j];
				int c = (int) ((height * 255.0 / 200.0) + (255.0/2.0));
				Color color = new Color(c, c, 255);
				g.setColor(color);
				g.fillRect(i*blocksize, j*blocksize, blocksize, blocksize);
			 */
			}
		}
	}
}