池塘夜降彩色雨
作者：中科大少年班 陈辉
作者主页：http://go2debug.yeah.net

下载本文示例源代码

程序运行效果图如下：


一、问题描述：
本程序是利用MFC制作的微软基础类应用程序，目的是模拟彩色雨滴滴落到池塘的情景，达到彩色雨滴从天而降，入水有声（尽管不怎么好听），产生圈圈涟漪。

二、数据结构：
主要的数据类型有两个带头结点的双向循环链表，这两个链表与MFC应用程序自动生成的对象类型混合使用，如下：

typedef struct {   //单个雨滴
	COLORREF color;//雨滴颜色
	bool visibility;   //可见性
	float radius; //半径
	float x;//雨滴中心位置 x
	float y;//雨滴中心位置 y
	float xvelocity;//雨滴速率 vx
	float yvelocity;//雨滴速率 vy
} droplet;

struct dropletchain {//所有雨滴组成的链表
	struct dropletchain * pre;
	droplet * drop;
	struct dropletchain * next;
};


typedef struct {//单个涟漪
	COLORREF color;//颜色
	float xdrop;//涟漪中心 x
	float ydrop;//涟漪中心 y
	float radius;//涟漪半径
	int shown;//是否绘制涟漪（这个参数在判断是否需要重绘时用到）
}ripple;

struct ripplechain {//  所有涟漪组成的链表
	struct ripplechain * pre;
	ripple * aripple;
	struct ripplechain * next;
};

struct dropletchain dc;
struct ripplechain rc;

dc.drop=NULL;
dc.pre=&dc;
dc.next=&dc;
rc.aripple=NULL;
rc.pre=&rc;
rc.next=&rc;

while(!this->endthread )
{
	draw();	
	draw();
	drive();	
}

PaintWindDC->SetROP2(R2_XORPEN);

adropchain=dc.next;
while(adropchain!=&dc)
{
	adrop=adropchain->drop;
	adrop->x+=(adrop->xvelocity+xacce) ;//计算下个时刻的雨点位置
	adrop->y+=(adrop->yvelocity+yacce) ;
	if(adrop->x>aRect.right ||
		adrop->x<aRect.left ||
		adrop->y<aRect.top||
		adrop->y>aRect.bottom )//分析雨点是否越界，是则删去
		{
			adropchain->next->pre=adropchain->pre;
			adropchain=adropchain->next;
			delete adropchain->pre->next->drop ;
			delete adropchain->pre->next ;
			adropchain->pre->next=adropchain;
			this->m_dropnumber --;
			sprintf(s,"%d",m_dropnumber);
			this->SetDlgItemText(IDC_EDIT5,s);
		}
	else if(adrop->y>Rect1.top+40 && rand()%4==1)//雨点到达水面则删去此雨点并产生新涟漪
	{
		struct ripplechain * arc=new struct ripplechain;
		ripple * aripple=new ripple;
		arc->aripple =aripple;
		aripple->color=adrop->color ;//删去的雨点和新生的涟漪颜色相同
		aripple->radius =adrop->radius ;//初始半径也相同
		aripple->xdrop =adrop->x;//初位置传递下来
		aripple->ydrop =adrop->y;
		aripple->shown =0;
		arc->next=rc.next ;
		arc->pre =&rc;
		rc.next->pre =arc;
		rc.next=arc;
	
		adropchain->next->pre=adropchain->pre;
		adropchain=adropchain->next;
		delete adropchain->pre->next->drop ;
		delete adropchain->pre->next ;
		adropchain->pre->next=adropchain;
		this->m_dropnumber --;
		sprintf(s,"%d",m_dropnumber);
		this->SetDlgItemText(IDC_EDIT5,s);
	
		this->m_ripplenumber ++;
		sprintf(s,"%d",m_ripplenumber);
		this->SetDlgItemText(IDC_EDIT6,s);
		if(rand()%10==1 && soundon) 
				Beep(4000,1);                      //落水有声
	}	
	else//对下个雨点进行判断
	{
		adropchain=adropchain->next;
	} 

aripplechain=rc.next;
while(aripplechain!=&rc)
{
	aripple=aripplechain ->aripple;
	if(aripple->radius>40 && aripple->shown ==0)//判断是否应删去此涟漪
	{
		aripplechain->next->pre=aripplechain->pre;
		aripplechain=aripplechain->next;
		delete aripplechain->pre->next->aripple  ;
		delete aripplechain->pre->next ;
		aripplechain->pre->next=aripplechain;
		this->m_ripplenumber --;
		sprintf(s,"%d",m_ripplenumber);
		this->SetDlgItemText(IDC_EDIT6,s);
	}
	else
	{
		aripple->radius +=1;//涟漪扩展
		aripplechain=aripplechain->next;//对下个涟漪进行判断
	}
}