#pas
procedure TViewerForm.FormPaint(Sender: TObject);

// This is the main paint routine. If there's no data assigned yet then an empty window is drawn else the data stored
// in the various lists. These lists must already be set up.

var Scale: Single;

begin
  // Note: We don't need to activate the rendering context here, as we did this in the OnShow event
  //       handler and we have setup the window to use a private DC (which is therefore never reset).
  ClearBuffersAndBackground;

  if FCameraChanged then             
  begin
    FCameraChanged := False;
    // set up projection 
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity;
    if NavPanel.Visible then
      ApplyPerspective(FViewport, ClientWidth - NavPanel.Width, ClientHeight, FDPI)
                        else
      ApplyPerspective(FViewport, Width, ClientHeight, FDPI);
  end;

  // initialize transformation pipeline
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity;

  // lights
  Scale := ScaleUpDown.Position / 1000;
  if FLightSourcesChanged then
  begin
    glScalef(Scale, Scale, Scale);
    SetupLights;
    glLoadIdentity;
  end;

  // camera
  gluLookAt(0, 0, 50,
            0, 0, -10,
            0, 1, 0);

  // objects
  if Abs(1 - Scale) > 0.1 then
  begin
    glEnable(GL_NORMALIZE);  // this will half the frame rate but is necessary for changing overall
                             // scale on the fly and still get the correct lighting
    glScalef(Scale, Scale, Scale);
  end
  else glDisable(GL_NORMALIZE);
  glMultMatrixf(@FSceneMatrix);
  if FMainList <> 0 then glCallList(FMainList);

  // copy back buffer to front
  SwapBuffers(Canvas.Handle);
end;

#pas
procedure THIGl_3dsMax._work_doDraw;
var     Scale: Single;
begin

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity;
  glMultMatrixf(@FSceneMatrix);
  if FMainList <> 0 then glCallList(FMainList);
  _hi_CreateEvent(_Data,@_event_onDraw);
end;