《图形学》实验四：中点Bresenham算法画直线

开发环境：

VC++6.0，OpenGL

实验内容：

使用中点Bresenham算法画直线。

实验结果：

代码：

 //中点Bresenham算法生成直线
 #include <gl/glut.h>
 #include <math.h>

 #define WIDTH    500        //窗口宽度
 #define HEIGHT    500        //窗口高度
 #define DRAWLINE1 MidpointBresenham(100,200,200,100);    //画直线
 #define DRAWLINE2 MidpointBresenham(200,100,450,400);    //画直线

 #pragma comment(linker, "/subsystem:\"windows\" /entry:\"mainCRTStartup\"")        //取消控制台

 void Init()    //初始化
 {
     glClearColor(1.0f,1.0f,1.0f,1.0f);    //设置背景颜色，完全不透明
     glColor3f(1.0f,0.0f,0.0f);    //设置画笔颜色

     glMatrixMode(GL_PROJECTION);            //设置投影
     gluOrtho2D(0.0, WIDTH, 0.0, HEIGHT);    //设置投影区域
 }

 void MidpointBresenham(int x0,int y0,int x1,int y1)    //中点Bresenham算法画线
 {
     int dx,dy,d,UpIncre,DownIncre,x,y;
     if(x0>x1){
         x=x1;x1=x0;x0=x;
         y=y1;y1=y0;y0=y;
     }
     x = x0,y = y0;
     dx = x1-x0;
     dy = y1-y0;
     if(dy>&&dy<=dx){    //0<k<=1
         d = dx-*dy;
         UpIncre = *dx-*dy;
         DownIncre = -*dy;
         while(x<=x1){
             glBegin(GL_POINTS);
             glVertex2i(x,y);
             glEnd();
             x++;
             if(d<){
                 y++;
                 d+=UpIncre;
             }
             else
                 d+=DownIncre;
         }
     }
     else if((dy>=(-dx))&&dy<=) //-1<=k<=0
     {
         d=dx-*dy;
         UpIncre=-*dy;
         DownIncre=-*dx-*dy;
         while(x<=x1)
         {
             glBegin(GL_POINTS);
             glVertex2i(x,y);
             glEnd();
             x++;
             if(d>)
             {
                 y--;
                 d+=DownIncre;
             }
             else d+=UpIncre;
         }
     }
     else if(dy<(-dx)) //k<-1
     {
         d=-dy-*dx;
         UpIncre=*dx+*dy;
         DownIncre=*dx;
         while(y>=y1)
         {
             glBegin(GL_POINTS);
             glVertex2i(x,y);
             glEnd();
             y--;
             if(d<)
             {
                 x++;
                 d-=UpIncre;
             }
             else d-=DownIncre;
         }
     }

     else //k>1和k不存在
     {
         d=dy-*dx;
         UpIncre=*dy-*dx;
         DownIncre=-*dx;
         while(y<=y1)
         {
             glBegin(GL_POINTS);
             glVertex2i(x,y);
             glEnd();
             y++;
             if(d<)
             {
                 x++;
                 d+=UpIncre;
             }
             else d+=DownIncre;
         }
     }
 }

 void Display()    //显示函数
 {
     glClear(GL_COLOR_BUFFER_BIT);    //清空颜色堆栈

     DRAWLINE1    //画直线
     DRAWLINE2    //画直线

     glFlush();    //清空缓冲区指令
 }

 int main(int argc,char** argv)
 {
     glutInit(&argc,argv);
     glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);    //初始化显示模式
     glutInitWindowSize(WIDTH,HEIGHT);    //设置窗口尺寸
     glutInitWindowPosition(,);    //设置窗口位置
     glutCreateWindow("画直线");    //创建窗口

     glutDisplayFunc(Display);    //注册显示函数
     Init();        //初始化
     glutMainLoop();    //进入程序循环
     return ;
 }

Freecode : www.cnblogs.com/yym2013