使用opengl 绘制9个点，理解各个参数的含义

 1 // SimpleTest1.cpp : 定义控制台应用程序的入口点。
 2 //
 3 
 4 #include "stdafx.h"
 5 #include<gl/glut.h>
 6 #include<iostream>
 7 using namespace std;
 8 void DrawTriggle()
 9 {
10     glPointSize(20);
11     glColor4f(1.0,0.0,0.0,0.6);
12     glColor4f(0.5,0.8,0,0.6);
13     glBegin(GL_POINTS);
14         glVertex3f(0.0,0.0,0.0);
15         glVertex3f(0.9,0.0,0.0);
16         glVertex3f(0.9,0.9,0.0);
17         glVertex3f(0.0,0.9,0.0);
18     glEnd();
19     glColor4f(0.3,0,1,0.6);
20     glBegin(GL_POINTS);
21         glVertex3f(-0.9,0.9,0.0);
22     glEnd();
23 glColor4f(1,0,0.1,0.6);
24     glBegin(GL_POINTS);
25         glVertex3f(-0.9,0.0,0.0);
26         glVertex3f(-0.9,-0.9,0.0);
27     glEnd();
28     glColor4f(1,0,0.5,0.1);
29     glBegin(GL_POINTS);
30         glVertex3f(0.9,-0.9,0.0);
31         glVertex3f(0.0,-0.9,0.0);
32     glEnd();
33     glFlush();
34 }
35 
36 void init()
37 {
38     glClearColor(1.0,1.0,1.0,0.0);
39     glutInitWindowPosition(300,300);
40     glutInitWindowSize(800,800);
41     glutCreateWindow("simpletest window");
42     gluLookAt(0.0,0.0,-1.0,0.0,0.0,-0.0,-100,0.0,0.0);
43     glutDisplayFunc(&DrawTriggle);
44 }
45 int _tmain(int argc, _TCHAR* argv[])
46 {
47     glutInit(&argc,(char**)argv);
48     glutInitDisplayMode(GLUT_RGBA  );
49     init();
50     std::cout<<"out: enter main loop"<<std::endl;;
51     glutMainLoop();
52     return 0;
53 }