如何使用glut openGL绘制四角星

#include <GL/glut.h>
#include <math.h>

void drawStar(float cx, float cy, float radius, int numPoints)
{
    float angle = 2 * 3.1415926 / numPoints;
    float halfAngle = angle / 2;

    glBegin(GL_TRIANGLE_FAN);
    glVertex2f(cx, cy); // 中心点

    for (int i = 0; i <= numPoints; i++)
    {
        float x = cx + radius * cos(i * angle);
        float y = cy + radius * sin(i * angle);
        glVertex2f(x, y);

        x = cx + radius / 2 * cos(i * angle + halfAngle);
        y = cy + radius / 2 * sin(i * angle + halfAngle);
        glVertex2f(x, y);
    }

    glEnd();
}

void renderScene()
{
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(1.0, 1.0, 0.0); // 设置颜色为黄色

    // 绘制四角星
    drawStar(0.0, 0.0, 0.5, 5);

    glFlush();
}

void init()
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(-1.0, 1.0, -1.0, 1.0);
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(500, 500);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("OpenGL Star");
    glutDisplayFunc(renderScene);
    init();
    glutMainLoop();

    return 0;
}