title: glRotatef does not rotate anything
body: <p>here's the problem:
  my triangle not rotating! 
  Why? What I've done wrong?</p>
  
  <p>Here's the code:</p>
  
  <p>main.cpp</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;GL/glut.h&gt;
  #include &lt;GL/gl.h&gt;
  #include "myobject.h"
  
  using namespace std;
  
  Vector3f position = Vector3f(0.0f,0.0f,0.0f);
  
  myobject *Ob = new myobject(position);
  
  float _angle = 0.1f;
  
  void render(){
      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
      glMatrixMode(GL_MODELVIEW);
      glLoadIdentity();      
  
      _angle += 0.4f;
  
      glPushMatrix();  
            glTranslatef (0.0f, -0.0f, -0.2f);
            glRotatef(_angle, 1.0f, 0.0f, 0.0f);
            Ob-&gt;draw();
      glPopMatrix();
  
      glutSwapBuffers();
  
  
  
  }
  
  void init(){
      glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
      glutInitWindowPosition(100,100);
      glutInitWindowSize(640, 480);
      glutCreateWindow("test");
  
      glutDisplayFunc(render);
  
      glutMainLoop();
  }
  
  
  int main(int argc, char * argv[]) {
  
      glutInit(&amp;argc, argv);
      init();
      return 0;
  }
  </code></pre>
  
  <p>myobject.cpp</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;GL/glut.h&gt;
  #include &lt;GL/gl.h&gt;
  #include "myobject.h"
  
  using namespace std;
  
  myobject::myobject(Vector3f pos)
  {
      _position = pos;
      _size = 0.0f;
  }
  
  myobject::~myobject()
  {
  }
  
  
  void myobject::draw()
  {
      glBegin(GL_TRIANGLES);
       glColor3f(0.2f,0.2f,0.5f);
       glVertex3f( 0.0f, 0.0f, 0.5f);  
       glVertex3f(-1.0f,-0.5f, 0.0f);  
       glVertex3f( 0.5f,-0.5f, 0.0f);  
      glEnd();
  }
  </code></pre>