text: #include<GL/glut.h>
  #include<gl/gl.h>
  #include<gl/GLU.h>
  
  void myDisplay()
  {
  	glClear(0x00004000);
  	//glClearColor(0.2f, 0.2f, 0.2f, 0.2f);
  	glRectf(-0.5f, -0.5f, 0.5f, 0.5f);
  	glFlush();
  }
  
  int main(int argc, char *argv[])
  {
  	glutInit(&argc, argv);
  	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
  	glutInitWindowPosition(100, 100);
  	glutInitWindowSize(400, 400);
  	glutCreateWindow("11612908 zhaoyu");
  	glutDisplayFunc(&myDisplay);
  	glutMainLoop();
  	return 0;
  }