1 #include "stdafx.h" 2 #include <GL/glut.h> 3 #include <stdlib.h> 4 #include <math.h> 5 #include <stdio.h> 6 7 const GLfloat PI = 3.14159265357f; 8 void myDisplay(void) { 9 GLfloat a = 1 / (2 - 2 * cos(72 * PI / 180)); 10 GLfloat bx = a*cos(18 * PI / 180); 11 GLfloat by = a*sin(18 * PI / 180); 12 GLfloat cy = -a*cos(18 * PI / 180); 13 GLfloat pointB[2] = { bx, by }, 14 pointC[2] = { 0.5, cy }, 15 pointD[2] = { -0.5, cy }, 16 pointE[2] = { -bx, by }, 17 pointA[2] = { 0,a }; 18 glClear(GL_COLOR_BUFFER_BIT); 19 20 //按照A->C->E->B->D->A的顺序一笔画出五角星 21 glBegin(GL_LINE_LOOP); 22 glVertex2fv(pointA); 23 glVertex2fv(pointC); 24 glVertex2fv(pointE); 25 glVertex2fv(pointB); 26 glVertex2fv(pointD); 27 glVertex2fv(pointA); 28 glEnd(); 29 glFlush(); 30 } 31 32 int main(int argc, char *argv[]) { 33 glutInit(&argc, argv); 34 glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); 35 glutInitWindowPosition(100, 100); 36 glutInitWindowSize(500, 500); 37 glutCreateWindow("OpenGL画圆程序"); 38 glutDisplayFunc(&myDisplay); 39 glutMainLoop(); 40 return 0; 41 }
运行结果如下所示：
