2021-11-04图形学 鼠标传点，连线，填充。（有人看就更新细节，其实创建类复制进去代码就能运行）

项目结构：

首先先声明两个全局变量int num；CPoint* points;
同时初始化。在view的构造函数里面：

CCbianbiaotianchongmonth10day302View::CCbianbiaotianchongmonth10day302View()
{
	// TODO: add construction code here
	num=0;
	points=new CPoint[20];
}

1. CAET类

// AET.h: interface for the CAET class.
//
//

#if !defined(AFX_AET_H__05106C7A_B056_438D_8CA1_E7953002D089__INCLUDED_)
#define AFX_AET_H__05106C7A_B056_438D_8CA1_E7953002D089__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

class CAET  
{
public:
	CAET();
	virtual ~CAET();
public:
	double  x;//当前扫描线与有效边交点的x坐标
	int     yMax;//边的最大y值
	double  k;//斜率的倒数(x的增量)
	CAET   *pNext;
};

#endif // !defined(AFX_AET_H__05106C7A_B056_438D_8CA1_E7953002D089__INCLUDED_)

2.CBucket类

// Bucket.h: interface for the CBucket class.
//
//

#if !defined(AFX_BUCKET_H__344AAEBF_5708_4B4B_BA14_67CC2969C43D__INCLUDED_)
#define AFX_BUCKET_H__344AAEBF_5708_4B4B_BA14_67CC2969C43D__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include "AET.h"

 
class CBucket  
{
public:
	CBucket();
	virtual ~CBucket();
public:
	int     ScanLine;     //扫描线
	CAET    *pET;         //桶上的边表指针
	CBucket *pNext;
};

#endif // !defined(AFX_BUCKET_H__344AAEBF_5708_4B4B_BA14_67CC2969C43D__INCLUDED_)

3. CFill类

// Fill.h: interface for the CFill class.
//
//

#if !defined(AFX_FILL_H__55C2E97E_0929_42CD_9555_59EF429F1283__INCLUDED_)
#define AFX_FILL_H__55C2E97E_0929_42CD_9555_59EF429F1283__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include "AET.h"
#include "Bucket.h"

 
class CFill  
{
public:
	void ClearMemory();//清理内存
	void DeleteAETChain(CAET* pAET);//删除边表
	CFill();
	virtual ~CFill();
	void SetPoint(CPoint *p,int m);
	void CreateBucket();//创建桶
	void CreateEdge();//边表
	void AddET(CAET *);//合并ET表
	void ETOrder();//ET表排序
	void Gouraud(CDC *);//填充多边形
 	
protected:
	int     PNum;//顶点个数
	CPoint    *P;//顶点坐标动态数组
	CAET    *pHeadE,*pCurrentE,*pEdge; //有效边表结点指针
	CBucket *pHeadB,*pCurrentB;        //桶表结点指针
};

#endif // !defined(AFX_FILL_H__55C2E97E_0929_42CD_9555_59EF429F1283__INCLUDED_)

4.鼠标左键传入点，右键连线。

void CCbianbiaotianchongmonth10day302View::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	
	CDC* pDC=GetDC();
	pDC->Ellipse(point.x-2,point.y-2,point.x+2,point.y+2);
	points[num]=point;
	num++;
	CView::OnLButtonDown(nFlags, point);
}

void CCbianbiaotianchongmonth10day302View::OnRButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	
if(num>=3){
	CDC * pDC=GetDC();
	pDC->Polygon(points,num);
	ReleaseDC(pDC);
	//num=0;
	}
	CView::OnRButtonDown(nFlags, point);
}

5.CFill类中所有函数的实现：

// Fill.cpp: implementation of the CFill class.
//
//
 
#include "stdafx.h"
#include "Cbianbiaotianchongmonth10day302.h"
#include "Fill.h"
#include "AET.h"
#include "Bucket.h"
 
#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif
//
// Construction/Destruction
//
CFill::CFill()
{
	PNum=0;
	P=NULL;
	pEdge=NULL;
	pHeadB=NULL;
	pHeadE=NULL;
	pCurrentB = NULL;
	pCurrentE = NULL;
}
 
CFill::~CFill()
{
	if(P!=NULL)
	{
		delete[] P;
		P=NULL;
	}
	ClearMemory();
}
 
void CFill::SetPoint(CPoint *p,int m)
{
	P=new CPoint[m];
	for(int i=0;i<m;i++)
	{
		P[i]=p[i];	
	}
	PNum=m;
}
 
void CFill::CreateBucket()
{
	int yMin,yMax;
	yMin = yMax = P[0].y;
	for(int i = 0;i<PNum;i++)
	{
		if(P[i].y<yMin)
		{
			yMin = P[i].y;
 
		}
		if(P[i].y>yMax)
		{
			yMax = P[i].y;
		}
	}
 
	for(int y = yMin;y<=yMax;y++)
	{
		if(yMin == y)
		{
			pHeadB = new CBucket;
			pCurrentB = pHeadB;
			pCurrentB->ScanLine = yMin;
			pCurrentB->pET = NULL;
			pCurrentB->pNext = NULL;
		}
		else
		{
			pCurrentB->pNext = new CBucket;
			pCurrentB=pCurrentB->pNext;
			pCurrentB->ScanLine = y;
			pCurrentB->pET=NULL;
			pCurrentB->pNext=NULL;
		}
	}
}
 
void CFill::CreateEdge()//创建边表，即将各边链入到相应的桶节点
{
	for(int i = 0;i<PNum;i++)
	{
		pCurrentB=pHeadB;
		int j = (i+1)%PNum;
		if(P[i].y<P[j].y)
		{
			pEdge = new CAET;
			pEdge->x=P[i].x;
			pEdge->yMax=P[j].y;
			pEdge->k = (double)(P[j].x-P[i].x)/((double)(P[j].y-P[i].y));
 
			pEdge->pNext = NULL;
			while(pCurrentB->ScanLine!=P[i].y)
			{
				pCurrentB=pCurrentB->pNext;
			}
		}
 
		if(P[j].y<P[i].y)
		{
			pEdge=new CAET;
			pEdge->x=P[j].x;
			pEdge->yMax=P[i].y;
			pEdge->k = (double)(P[i].x-P[j].x)/((double)(P[i].y-P[j].y));
			pEdge->pNext = NULL;
			while(pCurrentB->ScanLine!=P[j].y)
			{
				pCurrentB=pCurrentB->pNext;
			}
		}
 
		if(P[j].y!=P[i].y)
		{
			pCurrentE=pCurrentB->pET;
			if(pCurrentE==NULL)
			{
				pCurrentE=pEdge;
				pCurrentB->pET=pCurrentE;
			}
			else
			{
				while(NULL!=pCurrentE->pNext)
				{
					pCurrentE=pCurrentE->pNext;
				}
				pCurrentE->pNext=pEdge;
			}
		}
	}
}
void CFill::AddET(CAET *pNewEdge)//合并ET表
{
	CAET *pCE=pHeadE;//边表头结点
	if(pCE==NULL)//若边表为空，则pNewEdge作为边表头结点
	{
		pHeadE=pNewEdge;
		pCE=pHeadE;
	}
	else//将pNewEdge链接到边表末尾（未排序）
	{
		while(pCE->pNext!=NULL)
		{
			pCE=pCE->pNext;
		}
		pCE->pNext=pNewEdge;
	}
}
 
void CFill::ETOrder()//边表的冒泡排序算法
{
	CAET *pT1,*pT2;
	int Count=1;
	pT1=pHeadE;
	if(pT1==NULL)//没有边，不需要排序
	{
		return;
	}
	if(pT1->pNext==NULL)//如果该ET表没有再连ET表
	{
		return;//只有一条边，不需要排序
	}
	while(pT1->pNext!=NULL)//统计边结点的个数
	{
		Count++;
		pT1=pT1->pNext;
	}
	for(int i=0;i<Count-1;i++)//冒泡排序
	{
		CAET **pPre=&pHeadE;//pPre记录当面两个节点的前面一个节点，第一次为头节点
		pT1=pHeadE;
		for (int j=0;j<Count-1-i;j++)
		{
			pT2=pT1->pNext;
			
			if ((pT1->x>pT2->x)||((pT1->x==pT2->x)&&(pT1->k>pT2->k)))//满足条件，则交换当前两个边结点的位置
			{
				pT1->pNext=pT2->pNext;
				pT2->pNext=pT1;
				*pPre=pT2;
				pPre=&(pT2->pNext);//调整位置为下次遍历准备
			}
			else//不交换当前两个边结点的位置，更新pPre和pT1
			{
				pPre=&(pT1->pNext);
				pT1=pT1->pNext;
			}
		}
	}
}
 
void CFill::Gouraud(CDC *pDC)//填充多边形
{
	CAET *pT1=NULL,*pT2=NULL;
	pHeadE=NULL;
	for(pCurrentB=pHeadB;pCurrentB!=NULL;pCurrentB=pCurrentB->pNext)
	{
		for(pCurrentE=pCurrentB->pET;pCurrentE!=NULL;pCurrentE=pCurrentE->pNext)
		{
			pEdge=new CAET;
			pEdge->x=pCurrentE->x;
			pEdge->yMax=pCurrentE->yMax;
			pEdge->k=pCurrentE->k;
			pEdge->pNext=NULL;
			AddET(pEdge);
		}
 
		ETOrder();
		pT1=pHeadE;
		if(pT1==NULL)
		{
			return ;
		}
		while(pCurrentB->ScanLine>=pT1->yMax)
		{
			CAET *pAETTEmp = pT1;
			pT1=pT1->pNext;
			delete pAETTEmp;
			pHeadE=pT1;
			if(pHeadE==NULL)
			{
				return;
			}
 
		}
		if(pT1->pNext!=NULL)
		{
			pT2=pT1;
			pT1=pT2->pNext;
		}
 
		while(pT1!=NULL)
		{
			if(pCurrentB->ScanLine>=pT1->yMax)
			{
				CAET *pAETTemp=pT1;
				pT2->pNext=pT1->pNext;
				pT1=pT2->pNext;
				delete pAETTemp;
			}
			else
			{
				pT2=pT1;
				pT1=pT2->pNext;
			}
		}
		BOOL In = FALSE;
		int xb,xe;
		for(pT1=pHeadE;pT1!=NULL;pT1=pT1->pNext)
		{
			if(FALSE==In)
			{
				xb = (int)pT1->x;
				In=TRUE;
			}
			else
			{
				xe = (int)pT1->x;
				for(int x = xb;x<xe;x++)
				{
					pDC->SetPixel(x,pCurrentB->ScanLine,RGB(0,0,255));
				}
				In = FALSE;
 
			}
		}
		for(pT1=pHeadE;pT1!=NULL;pT1=pT1->pNext)
		{
			pT1->x=pT1->x+pT1->k;
		}
	}
}
 
 
void CFill::ClearMemory()//安全删除所有桶与桶上连接的边
{
	DeleteAETChain(pHeadE);//删除边表
	CBucket *pBucket=pHeadB;
	while (pBucket!=NULL)//针对每一个桶
	{
		CBucket *pBucketTemp=pBucket->pNext;
		DeleteAETChain(pBucket->pET);//删除桶上面的边
		delete pBucket;
		pBucket=pBucketTemp;
	}
	pHeadB=NULL;
	pHeadE=NULL;
}
 
void CFill::DeleteAETChain(CAET *pAET)//删除边表
{
	while (pAET!=NULL)
	{
		CAET *pAETTemp=pAET->pNext;
		delete pAET;
		pAET=pAETTemp;
	}
}

6.菜单的类向导：

上图填充的类向导函数如下：

void CCbianbiaotianchongmonth10day302View::OnFillllll() 
{
	// TODO: Add your command handler code here
	CDC* pDC = GetDC();
	//声明Fill类
	CFill *cFill = new CFill;
	
	cFill->SetPoint(points,num);
	
	cFill->CreateBucket();
 
	cFill->CreateEdge();
	
	cFill->Gouraud(pDC);
	
}