title: switch from glOrtho to gluPerspective
body: <p>I have a car draw at (0,0) and some obstacles set up but right now my main concern is switching from glPerspective to glOrtho and vice-versa. All that i get when i switch from perspective to ortho is a black screen.</p>
  
  <pre><code>void myinit(){
      glClearColor(0.0,0.0,0.0,0.0);
      glMatrixMode(GL_PROJECTION);
      glLoadIdentity();
      gluPerspective(60,ww/wh,1,100);
      glMatrixMode(GL_MODELVIEW);
      glLoadIdentity();
      gluLookAt(-5,5,3,backcarx,topcarx,0,0,0,1);
  }
  
  void menu(int id){
      /*menu selects if you want to view it in ortho or perspective*/
      if(id == 1){
          glClear(GL_DEPTH_BUFFER_BIT);
          glViewport(0,0,ww,wh);
          glMatrixMode(GL_PROJECTION);
          glLoadIdentity();
          glOrtho(-2,100,-2,100,-1,1);
          glMatrixMode(GL_MODELVIEW);
          glutPostRedisplay();
      }
      if(id == 2){
          glMatrixMode(GL_PROJECTION);
          glLoadIdentity();
          gluPerspective(60,ww/wh,1,100);
          glMatrixMode(GL_MODELVIEW);
          glLoadIdentity();
          viewx = backcarx - 10;
          viewy = backcary - 10;
          gluLookAt(viewx,viewy,viewz,backcarx,topcarx,0,0,0,1);
      }
  }
  </code></pre>
  
  <p>i've tried using the clear depth buffer and still doesnt work.</p>