水波动画

[qyxqyxqyx]

http://wenku.baidu.com/view/debd152fb4daa58da0114a9b.html
这个方法。我用C++，在window下GDI+重新实现了一下，然后试验了，发现效果不太好为啥？

#ifndef MYMATRIX_H
#define MYMATRIX_H

#include <iostream>

template<typename T>
class MyMatrix{
public:


private:
	T * buffer;
	unsigned int width;
	unsigned int height;

public:
	MyMatrix(unsigned int w , unsigned int h ):width(w),height(h){
		buffer = new T[width*height];
	}
	~MyMatrix(){
		delete []buffer;
	}
	inline bool Get(unsigned int i,unsigned int j,T * value = NULL)const{
		if(width == 0 || height == 0)return false;
		if(i>=width || j>=height)return false;		
		if(value!=NULL){
			*value = buffer[ i * width + j ];
			return true;
		}
		return false;
	}
	inline bool Set(unsigned int i,unsigned int j,const T & value = T()){
		if(width == 0 || height == 0)return false;
		if(i>=width || j>=height)return false;
		buffer[i*width+j] = value;
		return true;
	}
	inline void Init(const T & value = T()){
		for(unsigned int i = 0;i<width*height;++i){
			buffer[i] = value;
		}
	}
	inline const unsigned int & GetWidth()const{
		return width;
	}
	inline const unsigned int & GetHeight()const{
		return height;
	}
	void print(){
		T temp;
		for(unsigned int i = 0 ;i<height ; ++i){
			for(unsigned int j=0;j<width;++j){
				this->Get(i,j,&temp);
				std::cout<<temp<<"\t";
			}
			std::cout<<std::endl;
		}
	}
};

#endif

#ifndef RIPPLE_H
#define RIPPLE_H

#include "MyMatrix.h"
#include <utility>
#define delta 0.1

//扔石头,能量值为32-128
void DropStone(MyMatrix<float> * matrix,unsigned int i,unsigned int j,unsigned int size,float energy){
	unsigned int left = std::max<unsigned int>(i-size,(unsigned int)0);
	unsigned int top  = std::max<unsigned int>(j-size,(unsigned int)0);
	unsigned int right = std::min<unsigned int>(i+size,matrix->GetWidth());
	unsigned int bottom = std::min<unsigned int>(j+size,matrix->GetHeight());
	
	unsigned int center_x = i,center_y = j;

	for(unsigned int i=top;i<bottom;++i){
		for (unsigned int j=left;j<right;++j)
		{
			if(sqrt((i-center_x)*(i-center_x)+(j-center_y)*(j-center_y))<size){
				matrix->Set(i,j,-energy);
			}
		}
	}
}

void RippleSpread(MyMatrix<float> * matrix,bool * isEnd = NULL){
	int nWidth = matrix->GetWidth();
	int nHeight = matrix->GetHeight();
	float temp,up,down,left,right;
	bool end = true;

	if(nWidth>=3 && nHeight>=3){
		for(int i = 1;i<nHeight-1;++i){
			for (int j = 1;j<nWidth-1;++j)
			{
				matrix->Get(i-1,j,&up);
				matrix->Get(i+1,j,&down);
				matrix->Get(i,j-1,&left);
				matrix->Get(i,j+1,&right);

				if( abs(up)<delta )
					up=0;
				if( abs(down)<delta )
					down=0;
				if( abs(left)<delta )
					left=0;
				if( abs(right)<delta )
					right=0;

				if(up!=0 || down!=0 || left!=0 || right!=0)end = false;
				matrix->Get(i,j,&temp);
				temp = (up+down+left+right)/2-temp;
				temp -= temp/32;
				if( abs(temp)<delta )temp=0;
				matrix->Set(i,j,temp);
			}
		}
	}

	if (isEnd!=NULL)
	{
		*isEnd = end;
	}
}

#endif

CPaintDC dc(this); // 用于绘制的设备上下文
	
	// TODO: 在此处添加消息处理程序代码
	CRect rect;
	GetClientRect( &rect );
	int x = rect.CenterPoint().x;
	int y = rect.CenterPoint().y;
	int nWidth = rect.Width();
	int nHeight = rect.Height();

	HDC screenHdc = ::GetDC(NULL);

	Graphics graph(dc.m_hDC); // 创建图形对象
	//Graphics graph(screenHdc);

	using Gdiplus::Font;FontFamily fontFamily( L"宋体" );Font font( &fontFamily , 20);
	Image img(L"C:\\Users\\qianyuxiang\\Desktop\\米老鼠和唐老鸭.bmp");

	Bitmap bitmap( L"C:\\Users\\qianyuxiang\\Desktop\\米老鼠和唐老鸭.bmp" );
	Color oldColor,newColor;BYTE a,r,g,b;
	int w = bitmap.GetWidth(),h = bitmap.GetHeight();

	Color whiteTransparent = Color::MakeARGB(100,255,255,255);

	if(!matrix){
		matrix = new MyMatrix<float>(w,h);
		DropStone(matrix,h/2,w/2,30,128);
	}

	Bitmap * bitmap_done = bitmap.Clone(0,0,w,h,PixelFormat32bppARGB);

	static bool isEnd = false;

	#ifdef _D
	int delta_x,delta_y,position_x,position_y;
	float left,right,up,down;

	RippleSpread(matrix,&isEnd);

	for(int i=0;i<w;++i)
	{
		for (int j=0;j<h;++j)
		{
			if (i!=0 && i!=w-1 && j!=0 && j!=h-1)
			{
				matrix->Get(j,i+1,&right);
				matrix->Get(j,i-1,&left);
				matrix->Get(j-1,i,&up);
				matrix->Get(j+1,i,&down);
				delta_x=right-left;
				delta_y=up-down;
				position_x=std::max<unsigned int>(0,std::min<unsigned int>(w-1,i+delta_x));
				position_y=std::max<unsigned int>(0,std::min<unsigned int>(h-1,j+delta_y));
				bitmap_done->GetPixel(i,j,&oldColor);
				bitmap_done->SetPixel(position_x,position_y,oldColor);
			}
		}
	}
	#endif

实现了之后发现就是杂乱无章的乱窜，没有水纹的效果。
原理的倒数第二步，根据波能数据缓冲区对离屏页面进行渲染，意思是将左右点的插值和上下点的差值，作为该点处像素的平移向量吗？