《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：

 1 //中点Bresenham算法生成直线

 2 #include <gl/glut.h>

 3 #include <math.h>

 4 

 5 #define WIDTH    500        //窗口宽度

 6 #define HEIGHT    500        //窗口高度

 7 #define DRAWLINE1 MidpointBresenham(100,200,200,100);    //画直线

 8 #define DRAWLINE2 MidpointBresenham(200,100,450,400);    //画直线

 9 

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

 11 

 12 void Init()    //初始化

 13 {  14     glClearColor(1.0f,1.0f,1.0f,1.0f);    //设置背景颜色，完全不透明

 15     glColor3f(1.0f,0.0f,0.0f);    //设置画笔颜色

 16     

 17     glMatrixMode(GL_PROJECTION);            //设置投影

 18     gluOrtho2D(0.0, WIDTH, 0.0, HEIGHT);    //设置投影区域

 19 }  20 

 21 void MidpointBresenham(int x0,int y0,int x1,int y1)    //中点Bresenham算法画线

 22 {  23     int dx,dy,d,UpIncre,DownIncre,x,y;  24     if(x0>x1){  25         x=x1;x1=x0;x0=x;  26         y=y1;y1=y0;y0=y;  27  }  28     x = x0,y = y0;  29     dx = x1-x0;  30     dy = y1-y0;  31     if(dy>0&&dy<=dx){    //0<k<=1

 32         d = dx-2*dy;  33         UpIncre = 2*dx-2*dy;  34         DownIncre = -2*dy;  35         while(x<=x1){  36  glBegin(GL_POINTS);  37  glVertex2i(x,y);  38  glEnd();  39             x++;  40             if(d<0){  41                 y++;  42                 d+=UpIncre;  43  }  44             else

 45                 d+=DownIncre;  46  }  47  }  48     else if((dy>=(-dx))&&dy<=0) //-1<=k<=0

 49  {  50         d=dx-2*dy;  51         UpIncre=-2*dy;  52         DownIncre=-2*dx-2*dy;  53         while(x<=x1)  54  {  55  glBegin(GL_POINTS);  56  glVertex2i(x,y);  57  glEnd();  58             x++;  59             if(d>0)  60  {  61                 y--;  62                 d+=DownIncre;  63  }  64             else d+=UpIncre;  65  }  66  }  67     else if(dy<(-dx)) //k<-1

 68  {  69         d=-dy-2*dx;  70         UpIncre=2*dx+2*dy;  71         DownIncre=2*dx;  72         while(y>=y1)  73  {  74  glBegin(GL_POINTS);  75  glVertex2i(x,y);  76  glEnd();  77             y--;  78             if(d<0)  79  {  80                 x++;  81                 d-=UpIncre;  82  }  83             else d-=DownIncre;  84  }  85  }  86     

 87     else //k>1和k不存在

 88  {  89         d=dy-2*dx;  90         UpIncre=2*dy-2*dx;  91         DownIncre=-2*dx;  92         while(y<=y1)  93  {  94  glBegin(GL_POINTS);  95  glVertex2i(x,y);  96  glEnd();  97             y++;  98             if(d<0)  99  { 100                 x++; 101                 d+=UpIncre; 102  } 103             else d+=DownIncre; 104  } 105  } 106 } 107 

108 void Display()    //显示函数

109 { 110     glClear(GL_COLOR_BUFFER_BIT);    //清空颜色堆栈

111     

112     DRAWLINE1    //画直线

113     DRAWLINE2    //画直线

114     

115     glFlush();    //清空缓冲区指令

116 } 117 

118 int main(int argc,char** argv) 119 { 120     glutInit(&argc,argv); 121     glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);    //初始化显示模式

122     glutInitWindowSize(WIDTH,HEIGHT);    //设置窗口尺寸

123     glutInitWindowPosition(200,100);    //设置窗口位置

124     glutCreateWindow("画直线");    //创建窗口

125     

126     glutDisplayFunc(Display);    //注册显示函数

127     Init();        //初始化

128     glutMainLoop();    //进入程序循环

129     return 0; 130 }

 

Freecode : www.cnblogs.com/yym2013