www.pudn.com > 02824619.rar > ael.cpp

#include  
#include  
#include  
#include  
#include  
#include  
#define SCREEN_WIDTH   500 
 
//----------------------------------- 
//Here, please define your own data structure for edge Table, Active Edge Table, Edge 
//----------------------------------- 
typedef struct tEdge                                //边的结构体 
{ 
	int yUpper;                                    //边的最大Y值 
	float xIntersect,dxPerScan;                    //扫描线与边的交点的X值，边斜率的倒数 
	struct tEdge *next;         
}Edge; 
 
typedef struct tdcPt                               //点的结构体 
{ 
    int x; 
	int y; 
}dcPt; 
 dcPt pts[15];                                    //存放顶点的数组 
 
 
void insertEdge(Edge *list,Edge *edge)            //插入边函数 ，按交点X的递增排序 
{ 
	Edge *p,*q=list; 
	p=q->next; 
	while(p!=NULL){                               //判断后续是否空 
		if(edge->xIntersect < p->xIntersect)       //判断后续与插入边分别交点的X值， 
   	      	p=NULL;                              //直到后者比前者小 
		else{ 
			q=p; 
			p=p->next;                             
		} 
	} 
	edge->next=q->next;                       //实现插入 
	q->next=edge; 
} 
 
int yNext(int k,int cnt,dcPt *pts)         //索引，返回下一条非平行的纵座标值 
{	int j; 
	if((k+1)>(cnt-1)) 
		j=0; 
	else 
		j=k+1; 
	while(pts[k].y==pts[j].y) 
		if((j+1)>(cnt-1)) 
			j=0; 
		else 
			j++; 
		return(pts[j].y); 
} 
void makeEdgeRec(dcPt lower,dcPt upper,  
				 int yComp,Edge *edge,Edge *edges[])         //创建多边形的边 
{ 
    edge->dxPerScan=(float)(upper.x-lower.x)/(upper.y-lower.y);  //dx 
	edge->xIntersect=(float)lower.x;                         //交点的x值 
	if(upper.yyUpper=upper.y-1; 
	else 
		edge->yUpper=upper.y; 
	insertEdge(edges[lower.y],edge); 
} 
void buildEdgeList(int cnt,dcPt *pts,Edge *edges[])   // 创建边表 
{ 
	Edge *edge; 
	dcPt v1,v2; 
	int i,yPrev=pts[cnt-2].y; 
	v1.x=pts[cnt-1].x; 
	v1.y=pts[cnt-1].y; 
	for(i=0;inext; 
	while(p){ 
		q=p->next; 
		insertEdge(active,p);         // 插入 
		p=q; 
	} 
} 
 
void deleteAfter (Edge *q)      //删除边 
{ 
	Edge *p=q->next; 
	q->next=p->next; 
	delete p; 
} 
void updateActiveList(int scan,Edge *active)      // 更新活化边表 
{ 
	Edge *q=active,*p=active->next; 
	while(p)                              //直到P空，即遍历活化边表 
		if(scan>=p->yUpper){ 
			p=p->next; 
			deleteAfter(q); 
		} 
		else{ 
			p->xIntersect=p->xIntersect+p->dxPerScan; 
			q=p; 
			p=p->next; 
		} 
} 
void resortActiveList(Edge *active)        //应用活化边表 
{ 
	Edge *q,*p=active->next; 
	active->next=NULL; 
	while(p){ 
		q=p->next; 
		insertEdge(active,p); 
		p=q; 
	} 
} 
 
void DrawPoint(int x, int y)                       //给定的画点函数 
{ 
 
	glBegin(GL_POINTS); 
	glVertex2d(x, y); 
	glEnd(); 
 
} 
 
void fillScan(int scan,Edge *active)                //扫描填充 
{ 
	Edge *p1,*p2; 
	float i; 
	p1=active->next; 
	while(p1){ 
		p2=p1->next; 
		for(i=p1->xIntersect;ixIntersect;i++) 
		{ 
			::glColor3f(1.0, 0.0, 0.0); 
		    DrawPoint((int)i,scan); 
		}          
		p1=p2->next; 
	} 
} 
void scanFill(int cnt,dcPt *pts)  
{ 
	Edge *edges[SCREEN_WIDTH],*active; 
	int i,scan;  
	for(i=0;inext=NULL; 
	} 
	buildEdgeList(cnt,pts,edges); 
	active=new Edge; 
	active->next=NULL; 
	for(scan=0;scannext) 
		{ 
			fillScan(scan,active); 
			updateActiveList(scan,active); 
			resortActiveList(active); 
		} 
	} 
} 
 
void CALLBACK Reshape(GLsizei w, GLsizei h)         //给定的 
{ 
	::glViewport(0, 0, w, h); 
	::glMatrixMode(GL_PROJECTION); 
	glLoadIdentity(); 
    if (w <= h)  
		gluOrtho2D (0.0, SCREEN_WIDTH, 0.0, SCREEN_WIDTH*(GLfloat)h/(GLfloat)w); 
    else  
		gluOrtho2D (0.0, (GLfloat)SCREEN_WIDTH*(GLfloat)w/(GLfloat)h, 0.0, SCREEN_WIDTH); 
     
	glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
	return; 
} 
 
int count; 
 
void CALLBACK Display()                           //给定的 
{ 
	::glColor3f(1.0, 1.0, 0.0); 
//----------------------------------- 
// use the function "DrawPoint"defined above to display 
// your scan conversion result here 
//----------------------------------- 
    glPointSize(5); 
    glClear(GL_COLOR_BUFFER_BIT); 
 
    scanFill(count,pts); 
    glFlush(); 
	auxSwapBuffers(); 
	return; 
} 
 
void Init()                                      //给定的初始化窗口 
{ 
	::auxInitDisplayMode(AUX_RGBA|AUX_SINGLE); 
	::auxInitPosition(0, 0, 500, 500); 
	::auxInitWindow("Scan algithmic"); 
 
	::glShadeModel(GL_FLAT); 
	::glClearColor(0.0, 0.0, 0.0, 0.0); 
} 
void main(int argc, char **argv) 
{ 
	Init(); 
//----------------------------------- 
// implement your scan conversion algorithm here! 
//----------------------------------- 
    cout<<"请输入要测试的多边形的顶点个数"<>count; 
    for(int i=0;i>pts[i].x>>pts[i].y; 
	} 
  
	::auxReshapeFunc(Reshape);	 
	::auxMainLoop(Display); 
	return ; 
}