Java Swing模拟水波纹扩散效果动画

基于Java语言模拟水波纹运动效果，分为两种方法，一种采用简单的叠加计算
不使用sine函数模拟水波纹，好处是计算量小，另外一种采用sine函数来计算
水波纹扩展，计算量大，但是效果比较真实。

第一种简单的叠加效果水波模拟，是很多简单的2D游戏中会用的，关键是计
算水波的迁移，然后剩以能量衰减因子。Java实现的代码如下：

for(y=1; y<waveWidth-1; y++) { 	for(x= 1; x<waveHeight-1; x++) 	{ 		int n = (waveMapData[current][y-1][x] +  				waveMapData[current][y+1][x] +  				waveMapData[current][y][x+1] + 				waveMapData[current][y][x-1])/2 - 				waveMapData[before][y][x]; 		// energy lost 		n = n - n / damp; 		/*if(Math.abs(n) >= Math.abs(-100)) 		{ 			n = n % Math.abs(-100); 		}*/ 		waveMapData[next][y][x] = n; 		// System.out.print(" " + n); 	} 	// System.out.println(); }

解释： 主要是利用前两个水波的位置，计算出下一个将要出现的水波的位置，因此非常
重要的是保存前两个水波的迁移信息，然后实现波的叠加计算，在加上能量损失
因子，即可获得下个波的位置。
这种方法模拟出来的水波不是很圆，如果想得到那种很圆的水波效果，建议看
这里：http://blog.csdn.net/jia20003/article/details/13159535
解释完水波模拟的原理部分，下面来说说JAVA Swing的动画原理
主要是利用一个线程来计算水波的新位置，然后重新绘制图片，图片绘制好
以后调用repaint（）方法，自动触发Swing重绘机制，实现刷新显示效果。
水波计算线程代码如下：

Thread animationThread = new Thread () {     @Override     public void run() {     	int k = 0;        while (true) {     	  startWaterWave();     	  // sinWaterRipple();     	  updateText("水波开展：" + k);           repaint();  // Refresh the display           try {              Thread.sleep(1000 / 30); // delay and yield to other threads           } catch (InterruptedException ex) { }           k++;           if(k>=100){         	  break;           }        }     }  };  animationThread.start();

最后说一下Java的一个数据Copy的函数System.arraycopy，如果在多维数据中交
换数据你可能发现由于它是指针交换，交换完以后对新的数组赋值会同时跑到旧的
里面去。这个是我在debug程序的时候才发现。惭愧啊！程序效果如下：



UI加水波计算的完全源代码如下：

package com.gloomyfish.water.ripple.study;  import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.image.BufferedImage; import java.io.File;  import javax.imageio.ImageIO; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.SwingUtilities;  import com.gloomyfish.filter.study.WaterFilter;  public class MyDemoUI extends JFrame implements ActionListener {  	/** 	 *  	 */ 	private static final long serialVersionUID = -3702707300863726479L; 	private BufferedImage textureImg = null; 	private BufferedImage resultImg = null; 	private int waveWidth = 40; 	private int waveHeight = 40; 	private int damp = 16; 	private int[][][] waveMapData; 	private int before = 0, current = 1, next = 2; 	private int x = 1, y = 1 /*n = 0*/; 	private WaterPixelRender imageRender; 	private WaterFilter filter; 	private JButton runBtn; 	private JLabel txtLabel; 	private boolean text = false; 	public MyDemoUI() 	{ 		super("Water Ripple");         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);           getContentPane().setLayout(new BorderLayout());                      // Display the window.           getContentPane().add(createWaterPanel(), BorderLayout.CENTER);           runBtn = new JButton("Run it");         runBtn.addActionListener(this);                  txtLabel = new JLabel();         txtLabel.setText("水纹：0");         getContentPane().add(runBtn, BorderLayout.SOUTH);         getContentPane().add(txtLabel, BorderLayout.NORTH);         setPreferredSize(new Dimension(300 + 25,500));           pack();           setVisible(true);   	} 	 	public void updateText(String textContent) 	{ 		txtLabel.setText(textContent); 		this.invalidate(); 	}  	private JPanel createWaterPanel() { 		try { 			File file = new File("D:\\resource\\flower_001.png"); 			textureImg = ImageIO.read(file); 			resultImg = textureImg; 			 		} catch (Exception e) { 			e.printStackTrace(); 		} 		imageRender = new WaterPixelRender(); 		filter = new WaterFilter(); 		JPanel wPanel = new JPanel() 		{ 			protected void paintComponent(Graphics g) { 				Graphics2D g2 = (Graphics2D) g; 				g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 				if (resultImg != null) { 					g2.drawImage(resultImg, 0, 0, resultImg.getWidth(), resultImg.getHeight(), null); 				} 			} 		}; 		return wPanel; 	} 	 	public void swapData() 	{ 		for(int i=0; i<waveWidth; i++) 		{ 			for(int j=0; j<waveHeight; j++) 			{ 				waveMapData[before][i][j] = waveMapData[current][i][j]; 				waveMapData[current][i][j] = waveMapData[next][i][j]; 			} 		} 	} 	 	public void simulateWaterRipple() 	{ 		x = 1; 		y = 1; 		//n = 0; 		waveMapData = new int[3][textureImg.getHeight()][textureImg.getWidth()]; 		waveWidth = textureImg.getHeight(); 		waveHeight = textureImg.getWidth(); 		for(int i=0; i<waveWidth; i++) 		{ 			for(int j=0; j<waveHeight; j++) 			{ 				waveMapData[next][i][j] = 0; 				waveMapData[current][i][j] = 0; 				waveMapData[before][i][j] = 0; 			} 		} 		waveMapData[current][waveWidth/2][waveHeight/2] = -300; 		Thread animationThread = new Thread () { 		    @Override 		    public void run() { 		    	int k = 0; 		       while (true) { 		    	  startWaterWave(); 		    	  // sinWaterRipple(); 		    	  updateText("水波开展：" + k); 		          repaint();  // Refresh the display 		          try { 		             Thread.sleep(1000 / 30); // delay and yield to other threads 		          } catch (InterruptedException ex) { } 		          k++; 		          if(k>=100){ 		        	  break; 		          } 		       } 		    } 		 }; 		 animationThread.start(); 	}      	protected void sinWaterRipple() { 		resultImg = filter.filter(textureImg, null); 		filter.setRadius(filter.getRadius() + 5); 		if(filter.getRadius() > 150) 		{ 			filter.setRadius(50); 		} 		float wl = filter.getWavelength(); 		if(wl > 4) 		{ 			wl = wl / 2; 		} 		else 		{ 			wl = 32; 		} 		filter.setWavelength(wl); 	}  	protected void startWaterWave(/*int sx, int sy, Graphics2D g2*/)  	{ 		for(y=1; y<waveWidth-1; y++) 		{ 			for(x= 1; x<waveHeight-1; x++) 			{ 				int n = (waveMapData[current][y-1][x] +  						waveMapData[current][y+1][x] +  						waveMapData[current][y][x+1] + 						waveMapData[current][y][x-1])/2 - 						waveMapData[before][y][x]; 				// energy lost 				n = n - n / damp; //				if(Math.abs(n) >= Math.abs(-100)) //				{ //					n = n % Math.abs(-100); //				} 				waveMapData[next][y][x] = n; 				// System.out.print(" " + n); 			} 			// System.out.println(); 		} 		// render image pixel and display water ripple at here 		imageRender.setWaveData(waveMapData[next]); 		resultImg = imageRender.filter(textureImg, null); 		// prepare for the next water ripple 		// Java System.arraycopy give very bad result due to reference issue!!!! 		// System.arraycopy(waveMapData[next], 0, waveMapData[current], 0, waveMapData[next].length); 		swapData(); 	}  	public static void main(String[] args) 	{ 		new MyDemoUI(); 	}  	@Override 	public void actionPerformed(ActionEvent e) { 		SwingUtilities.invokeLater(new Runnable() { 			public void run(){ 				simulateWaterRipple();		 			} 		});		 	} }

绘制水波像素的生产新图片的代码如下：

package com.gloomyfish.water.ripple.study;  import java.awt.image.BufferedImage;  import com.gloomyfish.filter.study.AbstractBufferedImageOp;   public class WaterPixelRender extends AbstractBufferedImageOp {  	private int[][] waveData; 	private double rIndex = 2.0; 	private int counter = 0; 	public WaterPixelRender() 	{ 		 	} 	 	public int[][] getWaveData() { 		return waveData; 	} 	public void setWaveData(int[][] waveData) { 		this.waveData = waveData; 	} 	@Override 	public BufferedImage filter(BufferedImage src, BufferedImage dest) { 		counter++; 		int width = src.getWidth();         int height = src.getHeight();          if ( dest == null )         	dest = createCompatibleDestImage( src, null );          int[] inPixels = new int[width*height];         int[] outPixels = new int[width*height];         getRGB( src, 0, 0, width, height, inPixels );         int index = 0;         int nrow = 0, ncol = 0;         for(int row=0; row<height-1; row++) {         	int ta = 0, tr = 0, tg = 0, tb = 0;         	for(int col=0; col<width-1; col++) {         		                 int xDiff = waveData[row+1][col] - waveData[row][col];             	int yDiff = waveData[row][col+1] - waveData[row][col];             	double xAngle = Math.atan(xDiff);             	double xRefraction = Math.asin( Math.sin( xAngle ) / rIndex );             	double xDisplace = Math.tan( xRefraction ) * xDiff ;              	double yAngle = Math.atan( yDiff );             	double yRefraction = Math.asin( Math.sin( yAngle ) / rIndex );             	double yDisplace =Math.tan(yRefraction ) * yDiff;              	if(xDiff < 0)              	{             		if(yDiff < 0)             		{             			nrow = (int)(row - xDisplace);             			ncol = (int)(col - yDisplace);             		}             		else             		{             			nrow = (int)(row - xDisplace);             			ncol = (int)(col + yDisplace);             		}             	}             	else             	{             		if(yDiff < 0)             		{             			nrow = (int)(row + xDisplace);             			ncol = (int)(col - yDisplace);             		}             		else             		{             			nrow = (int)(row + xDisplace);             			ncol = (int)(col + yDisplace);             		}             	}             	if(nrow < 0 || nrow >= height)             	{             		nrow = 0;             	}             	if(ncol < 0 || ncol >= width)             	{             		ncol = 0;             	}             	             	         		index = nrow * width + ncol;         		ta = (inPixels[index] >> 24) & 0xff;                 tr = (inPixels[index] >> 16) & 0xff;                 tg = (inPixels[index] >> 8) & 0xff;                 tb = inPixels[index] & 0xff;                 index = row * width + col;                 outPixels[index] = (ta << 24) | (tr << 16) | (tg << 8) | tb;         	}         }         setRGB( dest, 0, 0, width, height, outPixels );         return dest; 	} }

复制代码以后替换图片路径即可运行，转载请注明出处
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