title: I need help to move the "camera" over a tunnel in OpenGL
body: <p>I created a small scene in C and OpenGL. It is a plane with a small tunnel over it. I'm trying to move the OpenGL &quot;camera&quot; inside this tunnel. However, I've been having some difficult to configure perspective and the objects disapear as I translate the object (my idea was to rotate and translate the scene to enter the tunnel).</p>
  <p>I'm trying not to use additional lybraies, such as GLUT.</p>
  <p>Can someone help?</p>
  <pre><code>#include &lt;windows.h&gt;
  #include &lt;gl/gl.h&gt;
  
  #define sizeX  0.05f
  #define sizeY  0.75f
  #define incr 0.1
  
  double xyz[3] = {0,0,0};
  int op = 0;
  
  void incrAxis(int v){
      if(v != 0)
          xyz[op] += incr;
      else
          xyz[op] -= incr;
  
      printf(&quot;%f %f %f\n&quot;,xyz[0],xyz[1],xyz[2]);
  }
  
  void changeAxis(int v){
      op = op + v;
      if(op == 3)
          op = 0;
      else
          if(op &lt; 0)
              op = 2;
  }
  
  
  void draw(){
      double alt = -0.1;
      glBegin(GL_QUADS);
          glColor3f(0.5f, 0.5f, 0.5f);     // black plane
          glVertex3f( 0.275, 0.275, alt);
          glVertex3f( 0.275,-0.275, alt);
          glVertex3f(-0.275,-0.275, alt);
          glVertex3f(-0.275, 0.275, alt);
      glEnd();
  
      glBegin(GL_QUADS);
          glColor3f(1.0f, 1.0f, 1.0f);     // plane
          glVertex3f( 0.75, 0.75, 0.0f);
          glVertex3f( 0.75,-0.75, 0.0f);
          glVertex3f(-0.75,-0.75, 0.0f);
          glVertex3f(-0.75, 0.75, 0.0f);
      glEnd();
  
      glBegin(GL_QUADS);
          glColor3f(0.0f, 1.0f, 0.0f);
          glVertex3f( sizeX, sizeY, -sizeX);
          glVertex3f( sizeX,-sizeY, -sizeX);
          glVertex3f(-sizeX,-sizeY, -sizeX);
          glVertex3f(-sizeX, sizeY, -sizeX);
      glEnd();
  
      glBegin(GL_QUADS);
          glColor3f(0.0f, 0.0f, 1.0f);
          glVertex3f(-sizeX, -sizeY, 0.0f);
          glVertex3f(-sizeX, -sizeY, -sizeX);
          glVertex3f(-sizeX, sizeY, -sizeX);
          glVertex3f(-sizeX, sizeY, 0.0f);
      glEnd();
  
      glBegin(GL_QUADS);
          glColor3f(1.0f, 0.0f, 0.0f);
          glVertex3f(sizeX, -sizeY, 0.0f);
          glVertex3f(sizeX, -sizeY, -sizeX);
          glVertex3f(sizeX, sizeY, -sizeX);
          glVertex3f(sizeX, sizeY, 0.0f);
      glEnd();
  
      glBegin(GL_QUADS);
          glColor3f(1.0f, 1.0f, 0.0f);
          glVertex3f(-sizeX, sizeY, 0.0f);
          glVertex3f(-sizeX, sizeY, -sizeX);
          glVertex3f( sizeX, sizeY, -sizeX);
          glVertex3f( sizeX, sizeY, 0.0f);
      glEnd();
  
  }
  
  LRESULT CALLBACK WindowProc(HWND, UINT, WPARAM, LPARAM);
  void EnableOpenGL(HWND hwnd, HDC*, HGLRC*);
  void DisableOpenGL(HWND, HDC, HGLRC);
  
  
  int WINAPI WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpCmdLine,
                     int nCmdShow)
  {
      WNDCLASSEX wcex;
      HWND hwnd;
      HDC hDC;
      HGLRC hRC;
      MSG msg;
      BOOL bQuit = FALSE;
  
      /* register window class */
      wcex.cbSize = sizeof(WNDCLASSEX);
      wcex.style = CS_OWNDC;
      wcex.lpfnWndProc = WindowProc;
      wcex.cbClsExtra = 0;
      wcex.cbWndExtra = 0;
      wcex.hInstance = hInstance;
      wcex.hIcon = LoadIcon(NULL, IDI_APPLICATION);
      wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
      wcex.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
      wcex.lpszMenuName = NULL;
      wcex.lpszClassName = &quot;GLSample&quot;;
      wcex.hIconSm = LoadIcon(NULL, IDI_APPLICATION);;
  
  
      if (!RegisterClassEx(&amp;wcex))
          return 0;
  
      /* create main window */
      hwnd = CreateWindowEx(0,
                            &quot;GLSample&quot;,
                            &quot;OpenGL Sample&quot;,
                            WS_OVERLAPPEDWINDOW,
                            CW_USEDEFAULT,
                            CW_USEDEFAULT,
                            512,
                            512,
                            NULL,
                            NULL,
                            hInstance,
                            NULL);
  
      ShowWindow(hwnd, nCmdShow);
  
      /* enable OpenGL for the window */
      EnableOpenGL(hwnd, &amp;hDC, &amp;hRC);
  
      /* program main loop */
      while (!bQuit)
      {
          /* check for messages */
          if (PeekMessage(&amp;msg, NULL, 0, 0, PM_REMOVE))
          {
              /* handle or dispatch messages */
              if (msg.message == WM_QUIT)
              {
                  bQuit = TRUE;
              }
              else
              {
                  TranslateMessage(&amp;msg);
                  DispatchMessage(&amp;msg);
              }
          }
          else
          {
              /* OpenGL animation code goes here */
  
              glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
              glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
              glPushMatrix();
              glTranslatef(xyz[0],xyz[1],xyz[2]);
  
              glRotatef(89, 1.0f, 0.0f, 0.0f);
              glRotatef(50, 0.0f, 1.0f, 0.0f);
              //glRotatef(5, 0.0f, 0.0f, 1.0f);
  
              draw();
  
              glPopMatrix();
  
              SwapBuffers(hDC);
  
              Sleep (1);
          }
      }
  
      /* shutdown OpenGL */
      DisableOpenGL(hwnd, hDC, hRC);
  
      /* destroy the window explicitly */
      DestroyWindow(hwnd);
  
      return msg.wParam;
  }
  
  LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
  {
      switch (uMsg)
      {
          case WM_CLOSE:
              PostQuitMessage(0);
          break;
  
          case WM_DESTROY:
              return 0;
  
          case WM_KEYDOWN:
          {
              switch (wParam)
              {
                  case VK_ESCAPE:
                      PostQuitMessage(0);
                  break;
                  case VK_RIGHT:
                      changeAxis(+1);
                      break;
                  case VK_DOWN:
                      incrAxis(0);
                      break;
                  case VK_LEFT:
                      changeAxis(-1);
                      break;
                  case VK_UP:
                      incrAxis(1);
                      break;
              }
          }
          break;
  
          default:
              return DefWindowProc(hwnd, uMsg, wParam, lParam);
      }
  
      return 0;
  }
  
  void EnableOpenGL(HWND hwnd, HDC* hDC, HGLRC* hRC)
  {
      PIXELFORMATDESCRIPTOR pfd;
  
      int iFormat;
  
      /* get the device context (DC) */
      *hDC = GetDC(hwnd);
  
      /* set the pixel format for the DC */
      ZeroMemory(&amp;pfd, sizeof(pfd));
  
      pfd.nSize = sizeof(pfd);
      pfd.nVersion = 1;
      pfd.dwFlags = PFD_DRAW_TO_WINDOW |
                    PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
      pfd.iPixelType = PFD_TYPE_RGBA;
      pfd.cColorBits = 24;
      pfd.cDepthBits = 16;
      pfd.iLayerType = PFD_MAIN_PLANE;
  
      iFormat = ChoosePixelFormat(*hDC, &amp;pfd);
  
      SetPixelFormat(*hDC, iFormat, &amp;pfd);
  
      /* create and enable the render context (RC) */
      *hRC = wglCreateContext(*hDC);
  
      wglMakeCurrent(*hDC, *hRC);
      glShadeModel(GL_SMOOTH);               // Enables Smooth Color Shading
      glClearDepth(1.0);                 // Depth Buffer Setup
      glEnable(GL_DEPTH_TEST);               // Enables Depth Testing
      glDepthFunc(GL_LESS);                  // The Type Of Depth Test To Do
      glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);//Realy Nice perspective calculations
  
  
      glMatrixMode( GL_PROJECTION );
      glLoadIdentity();
      glFrustum(-10, 10, -10, 10, -100, 100);
  
      glMatrixMode( GL_MODELVIEW );
      glLoadIdentity();
  }
  
  void DisableOpenGL (HWND hwnd, HDC hDC, HGLRC hRC)
  {
      wglMakeCurrent(NULL, NULL);
      wglDeleteContext(hRC);
      ReleaseDC(hwnd, hDC);
  }
  
  </code></pre>