drawwaterwave.java

基于ANdroid平台的一个应用程序 实现了背景的水波效果

/**
 * [e-mail]
 * 本程序可以随便使用，可以随便转载，但是希望尊重我的成果，请挂上本人博客
 * http://huojv.blog.hexun.com(有时间去看看，也许会有你要的东西)
 * 我老婆马艳，我会对你很好的！谢谢理解!
 * 2008-12-25
 */
package com.google.android.WaterWave;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.view.View;

public class DrawWaterWave extends View implements Runnable
{
    boolean bRunning = false;

    int BACKWIDTH;

    int BACKHEIGHT;

    short[] buf2;

    short[] buf1;

    int[] Bitmap2;

    int[] Bitmap1;
    
    public DrawWaterWave(Context context)
    {
    	super(context);
    	
    	Bitmap 		image = BitmapFactory.decodeResource(this.getResources(),R.drawable.bg);
    	BACKWIDTH = image.getWidth();
    	BACKHEIGHT = image.getHeight();
    	
        buf2 = new short[BACKWIDTH * BACKHEIGHT];
        buf1 = new short[BACKWIDTH * BACKHEIGHT];
        Bitmap2 = new int[BACKWIDTH * BACKHEIGHT];
        Bitmap1 = new int[BACKWIDTH * BACKHEIGHT];

        image.getPixels(Bitmap1, 0, BACKWIDTH, 0, 0, BACKWIDTH, BACKHEIGHT);
        
        start();
    }
    
    
    void DropStone(int x,//x坐标
            	   int y,//y坐标
            	   int stonesize,//波源半径
            	   int stoneweight)//波源能量
    {
        if ((x + stonesize) > BACKWIDTH || (y + stonesize) > BACKHEIGHT
                || (x - stonesize) < 0 || (y - stonesize) < 0)
            return;

        for (int posx = x - stonesize; posx < x + stonesize; posx++)
            for (int posy = y - stonesize; posy < y + stonesize; posy++)
                if ((posx - x) * (posx - x) + (posy - y) * (posy - y) < stonesize
                        * stonesize)
                    buf1[BACKWIDTH * posy + posx] = (short)-stoneweight;
    }

    
    protected void onDraw(Canvas canvas)
    {
    	canvas.drawBitmap(Bitmap2, 0, BACKWIDTH, 0, 0, BACKWIDTH, BACKHEIGHT, false, null);
    }

    public void start() 
    {
        bRunning = true;
        Thread t = new Thread(this);
        t.start();
    }

    public void key()
    {
    	DropStone(BACKWIDTH/2, BACKHEIGHT/2, 10, 50);
    }
    public void stop() 
    {
        bRunning = false;
    }
    public void run() 
    {
        
        while (bRunning) 
        {
//			try
//			{
//				Thread.sleep(50);
//			}catch(Exception e){e.printStackTrace();};
            RippleSpread();
            render();
        	postInvalidate();
        }
    }
    void RippleSpread()
    {
    	for (int i=BACKWIDTH; i<BACKWIDTH*BACKHEIGHT-BACKWIDTH; i++)
    	{
    		//波能扩散
    		buf2[i] = (short)(((buf1[i-1]+
    					buf1[i+1]+
    					buf1[i-BACKWIDTH]+
    					buf1[i+BACKWIDTH])
    					>>1)
    					- buf2[i]);
    		//波能衰减
    		buf2[i] -= buf2[i]>>5;
    	}

    	//交换波能数据缓冲区
    	short []ptmp =buf1;
    	buf1 = buf2;
    	buf2 = ptmp;
    }
    void render() {
    	int xoff, yoff;
    	int k = BACKWIDTH;
    	for (int i=1; i<BACKHEIGHT-1; i++)
    	{
    		for (int j=0; j<BACKWIDTH; j++)
    		{
    			//计算偏移量
    			xoff = buf1[k-1]-buf1[k+1];
    			yoff = buf1[k-BACKWIDTH]-buf1[k+BACKWIDTH];

    			//判断坐标是否在窗口范围内
    			if ((i+yoff )< 0 ) {k++; continue;}
    			if ((i+yoff )> BACKHEIGHT) {k++; continue;}
    			if ((j+xoff )< 0 ) {k++; continue;}
    			if ((j+xoff )> BACKWIDTH ) {k++; continue;}

    			//计算出偏移象素和原始象素的内存地址偏移量
    			int pos1, pos2;
    			pos1=BACKWIDTH*(i+yoff)+ (j+xoff);
    			pos2=BACKWIDTH*i+ j;    			
    			Bitmap2[pos2++]=Bitmap1[pos1++];
    			k++;
    		}
    	}
    }

}