开发环境：

VC++6.0，OpenGL

实验内容：

使用中点Bresenham算法画圆。

实验结果：

代码：

1 #include 
     
       2  3 #define WIDTH  500 4 #define HEIGHT 500 5 #define OFFSET 15 6 #define R 8 7  8 void Init()    //其它初始化 9 {10     glClearColor(1.0f,1.0f,1.0f,1.0f);    //设置背景颜色，完全不透明11     glColor3f(1.0f,0.0f,0.0f);        //设置画笔颜色12 13     glMatrixMode(GL_PROJECTION);14     glLoadIdentity();15     gluOrtho2D(0.0, 30.0, 0.0, 30.0);16     glMatrixMode(GL_MODELVIEW);17 18     //glMatrixMode(GL_PROJECTION);    //设置投影19     //gluOrtho2D(0.0,WIDTH,0.0,HEIGHT);    //设置20 }21 22 void CirclePoint(int x,int y)23 {24     glPointSize(5);    //设置点的粗细25     glBegin(GL_POINTS);26 27     glVertex2i(OFFSET+x,OFFSET+y);28     glVertex2i(OFFSET+y,OFFSET+x);29     glVertex2i(OFFSET-y,OFFSET+x);30     glVertex2i(OFFSET-x,OFFSET+y);31     glVertex2i(OFFSET-x,OFFSET-y);32     glVertex2i(OFFSET-y,OFFSET-x);33     glVertex2i(OFFSET+y,OFFSET-x);34     glVertex2i(OFFSET+x,OFFSET-y);35 36     glEnd();37 }38 39 void MidBresenhamCircle(int r)40 {41     int x,y,d;42     x=0,y=r,d=1-r;43     while(x<=y){44         CirclePoint(x,y);    //画圆45         if(d<0)46             d+=2*x+3;47         else{48             d+=2*(x-y)+5;49             y--;50         }51         x++;52     }53 }54 55 void Display()56 {57     glClear(GL_COLOR_BUFFER_BIT);    //清空颜色堆栈58 59     MidBresenhamCircle(R);    //画一个半径为150的圆（半径为8的太小了。。）60 61     glFlush();    //清空缓冲区指令62 }63 64 int main(int argc,char** argv)65 {66     glutInit(&argc,argv);67     glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);    //初始化显示模式68     glutInitWindowSize(WIDTH,HEIGHT);    //初始化窗口大小69     glutInitWindowPosition(200,100);    //初始化窗口出现位置70     glutCreateWindow("中点Bresenham画圆");    //初始化窗口标题71 72     glutDisplayFunc(Display);    //注册显示函数73     Init();        //其它初始化74     glutMainLoop();    //进入程序循环75 76     return 0;77 }
     

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