OpenGL基础（一）2.画多边形之圆

 1 //Five edges polygon.
 2 //As less code as possible.
 3
 4 #include "stdafx.h"
 5 #include<gl/glut.h>
 6 #include<stdlib.h>
 7 #include<iostream>
 8 #include<math.h>
 9
10 const GLdouble PI = 3.1415926;
11 static GLdouble x, y;
12 using namespace std;
13
14 void drawCircle(GLdouble radius, GLdouble divide)
15 {
16
17     for (int k = 0; k < divide; k++)
18     {
19         x = radius* cos((k / divide) * 2 * PI);
20         y = radius* sin((k / divide) * 2 * PI);
21         glColor3f((k/divide), 1.0, 1.0);
22         glVertex3d(x, y, 0.0);
23         cout << "(" << x << "," << y << "("<<endl;
24     }
25 }
26
27 void init(void)
28 {
29     glClearColor(0.0, 0.0, 0.0, 0.0);
30 }
31
32 void display(void)
33 {
34     glClear(GL_COLOR_BUFFER_BIT);
35
36
37     glBegin(GL_POLYGON);
38
39     drawCircle(0.8, 100);
40
41     glEnd();
42     glFlush();
43
44 }
45
46
47 int main(int argc, char** argv)
48 {
49     glutInit(&argc, argv);
50     glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
51     glutInitWindowPosition(500, 300);
52     glutInitWindowSize(500, 500);
53     glutCreateWindow("DrawGeometry");
54     init();
55     glutDisplayFunc(display);
56     glutMainLoop();
57     return 0;
58 }

画了一个圆

并打印输出x,y坐标