【openGL】画五角星

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

 const GLfloat PI = 3.14159265357f;
 void myDisplay(void) {
     GLfloat a =  / ( -  * cos( * PI / ));
     GLfloat bx = a*cos( * PI / );
     GLfloat by = a*sin( * PI / );
     GLfloat cy = -a*cos( * PI / );
     GLfloat pointB[] = { bx, by },
         pointC[] = { 0.5, cy },
         pointD[] = { -0.5, cy },
         pointE[] = { -bx, by },
         pointA[] = { ,a };
     glClear(GL_COLOR_BUFFER_BIT);

     //按照A->C->E->B->D->A的顺序一笔画出五角星
     glBegin(GL_LINE_LOOP);
     glVertex2fv(pointA);
     glVertex2fv(pointC);
     glVertex2fv(pointE);
     glVertex2fv(pointB);
     glVertex2fv(pointD);
     glVertex2fv(pointA);
     glEnd();
     glFlush();
 }

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

运行结果如下所示：