顾名思义啊，就是在OpenGL中用扫描填充算法画一个稍微复杂的图形：

#include

#include

#include

#include

#define COLOR_NEW 1.0,0.0,0.0

#define FALSE 0

#define TRUE 1

struct Point

{

int x;

int y;

Point(int a=0,int b=0)

{

x=a;

y=b;

}

};

struct Bian_list

{

float jx;

float dx;

int ymin;

int ymax;

bool sp;

};

struct Xb

{

float x[10];

int num;

};

struct Huo_list

{

int num;

Bian_list * next[10];

};

void InitiateHuo_list(Huo_list * H)

{

H->num=0;

H->next[0]=NULL;

}

void InsertHuo_list(Huo_list * H,Bian_list * b_list)

{

H->next[H->num]=b_list;

H->num++;

}

void Deleteb_list(Huo_list * H,int j)

{

int i;

for(i=j;inum;i++)

{

H->next[i]=H->next[i+1];

}

H->num--;

}

void pai_xuHuo_list(Xb * xb)

{

int n = xb->num;

int i,j;

float temp;

for (i=0;i

{

temp=xb->x[i+1];

j=i;

while(j>-1&&tempx[j])

{

xb->x[j+1]=xb->x[j];

j--;

}

xb->x[j+1]=temp;

}

}

//ScanLine用于设多边形存储的顶点序列，顶点数等于边数

void ScanLine(Point * Polygon_point,int num_point)

{

//point_ymax,point_ymin,num_smx用来确定扫描线链表的个数

int i,j,point_ymax,point_ymin,num_smx;

point_ymax=Polygon_point[1].y;

point_ymin=Polygon_point[1].y;

for(i=0;i

{

if (Polygon_point[i].y>point_ymax)

point_ymax=Polygon_point[i].y;

if (Polygon_point[i].y

point_ymin=Polygon_point[i].y;

}

num_smx=point_ymax-point_ymin;

//建立、初始化边表

Bian_list * b_list=(Bian_list * )malloc(num_point * sizeof(Bian_list));

//n个点n-1条边

for(i=0;i

{

//jx其实是保存扫描线与边的当前交点值，即ymin对应的jx,Cpoint(jx,ymin)

if(Polygon_point[i].y

b_list[i].jx=Polygon_point[i].x;

else

b_list[i].jx=Polygon_point[i+1].x;

if(Polygon_point[i].y!=Polygon_point[i+1].y)

{

//忽略斜率为无穷，即忽略水平线

b_list[i].dx=(float)(Polygon_point[i].x-Polygon_point[i+1].x)/

(Polygon_point[i].y-Polygon_point[i+1].y);

b_list[i].sp=FALSE;

}

else

{

//dx取较大的x

b_list[i].dx=(Polygon_point[i].x>Polygon_point[i+1].x)?Polygon_point[i].x:Polygon_point[i+1].x;

//jx取较小的x

b_list[i].jx=(Polygon_point[i].x

b_list[i].sp=TRUE;

}

b_list[i].ymax=(Polygon_point[i].y>Polygon_point[i+1].y)?Polygon_point[i].y:Polygon_point[i+1].y;

b_list[i].ymin=(Polygon_point[i].y

}

//建立、初始化新边表

Xb xb;

Huo_list * h_list=new(Huo_list);

h_list->num=0;

for(i=point_ymin;i

{

for(j=0;j

if(i==b_list[j].ymin)

{

InsertHuo_list(h_list,&b_list[j]);

}

int n=0;

xb.num=0;

while(nnum)

{

if(h_list->next[n]->sp)

{

xb.x[xb.num]=h_list->next[n]->jx;

xb.num++;

xb.x[xb.num]=h_list->next[n]->dx;

xb.num++;

}

else

{

xb.x[xb.num]=h_list->next[n]->jx+h_list->next[n]->dx * (i-h_list->next[n]->ymin);

xb.num++;

}

n++;

}

pai_xuHuo_list(&xb);

bool tc=FALSE;

for(j=0;j

{

int x,x1,xr;

x1=xb.x[j];

xr=xb.x[j+1];

x=x1;

while(x<=xr)

{

glColor3f(COLOR_NEW);

glVertex2i(x,i);

x++;

}

}

if(i==point_ymin)

i--;

i++;

for(j=0;jnum;j++)

if(i==h_list->next[j]->ymax)

{

Deleteb_list(h_list,j);

}

if(i==point_ymin)

i++;

}

}

void LineDDA(int x0,int y0,int x1,int y1)

{

float dy,dx,x,y,m;

dx=x1-x0;

dy=y1-y0;

if(dx!=0)

{

m=dy/dx;

if(m<=1&&m>=-1)

{

y=y0;

for(x=x0;x<=x1;x++)

{

y=y0;

for(x=x0;x<=x1;x++)

{

glVertex2i(x,int(y+0.5));

y+=m;

}

}

if(m>1||m

{

m=1/m;

x=x0;

for(y=y0;y<=y1;y++)

{

glVertex2i(int(x+0.5),y);

x+=m;

}

}

}else

{

int x=x0,y;

y=(y0<=y1)?y0:y1;

int d=fabs((double)(y0-y1));

while(d>=0)

{

glVertex2i(x,y);

y++;

d--;

}

}

}

}

void ScanLineSegment()

{

glClear(GL_COLOR_BUFFER_BIT);

glColor3f(0.0,0.0,0.0);

glBegin(GL_POINTS);

Point spt[8];

spt[0]=Point(230,230);

spt[1]=Point(290,230);

spt[2]=Point(275,280);

spt[3]=Point(230,280);

spt[4]=Point(245,260);

spt[5]=Point(250,254);

spt[6]=Point(235,245);

spt[7]=Point(230,230);

ScanLine(spt,8);

glEnd();

glFlush();

}

void main(int argc, char * argv[])

{

glutInit(&argc,argv);

glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

glutInitWindowPosition(50,100);

glutInitWindowSize(500,500);

glutCreateWindow("扫描填充算法");

glClearColor(1.0,1.0,1.0,0.0);

glMatrixMode(GL_PROJECTION);

gluOrtho2D(0.0,500.0,0.0,500.0);

glutDisplayFunc(ScanLineSegment);

glutMainLoop();

}