《图形学》实验四：中点Bresenham算法画直线

//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 ;
}