哪个懂opengl的指点一下小弟，我刚学。这个简单的程序怎么没有显示直线？？？

#include"windows.h"
#include"gl/gl.h"
#include"gl/glu.h"
#include"gl/glut.h"void RenderScene(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glBegin (GL_LINES);
glVertex2f(1.0,1.0);
glVertex2f(100.0,100.0);
glEnd();
glFlush();
}void SetupRC(void)
{
glClearColor(0.98f,0.625f,0.12f,1.0f);
glColor3f(1.0f,0.0f,0.0f);
}void main(void)
{
glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
glutCreateWindow("simple");

glutDisplayFunc(RenderScene);
         SetupRC();
glutMainLoop();
}