【openGL】画直线

 #include "stdafx.h"
 #include <GL/glut.h>
 #include <stdlib.h>
 #include <math.h>
 #include <stdio.h>

 using namespace std;

 void myDisplay(void){
     glClear(GL_COLOR_BUFFER_BIT);
     //glRectf(-0.5f, -0.5f, 0.5f, 0.5f);     

     glBegin(GL_LINES);
     glVertex2f(-0.5f, -0.5f);        //直线起始坐标
     glVertex2f(0.5f, 0.5f);         //直线结束坐标
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(-0.5f, 0.5f);
     glVertex2f(0.5f, -0.5f);
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(-0.5f, 0.5f);
     glVertex2f(-0.5f, -0.5f);
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(0.5f, 0.5f);
     glVertex2f(0.5f, -0.5f);
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(-0.5f, 0.5f);
     glVertex2f(0.5f, 0.5f);
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(-0.5f, -0.5f);
     glVertex2f(-0.5f, 0.5f);
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(, 0.5f);
     glVertex2f(, -0.5f);
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(-0.5f, -0.5f);
     glVertex2f(0.5, -0.5f);
     glEnd();

     glBegin(GL_LINES);
     glVertex2f(-0.5f, );
     glVertex2f(0.5, );
     glEnd();

     glFlush();
 }
 int main(int argc, char *argv[]) {
     glutInit(&argc, argv);
     glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
     glutInitWindowPosition(, );
     glutInitWindowSize(, );
     glutCreateWindow("第一个 OpenGL 程序");
     glutDisplayFunc(&myDisplay);
     glutMainLoop();
     return ;
 }

运行图像：