class TGLWidget: public TGFrame, public TGLPaintDevice

 Static constructor for creating widget with default pixel format.

 Static constructor for creating widget with given pixel format.

 Creates widget with default pixel format.

Destructor. Deletes window ???? and XVisualInfo

Call glEnable(... in overrider of InitGL.

Do actual drawing in overrider of PaintGL.

Make the gl-context current.

Clear the current gl-context.

Swap buffers.

Get gl context.

Pixel format.

Dpy*, XVisualInfo *

Register gl-context created for this window.

Remove context (no real deletion, done by TGLContex dtor).

For camera.

 CreateWidget.
 Static function called prior to widget construction,
 I've extracted this code from ctors to make WIN32/X11
 separation simpler and because of gInterpreter usage.
 new, TGLContext can throw
 std::bad_alloc and std::runtime_error. Before try block, the only
 resource allocated is pointed by fWindowIndex (InitWindow cannot throw).
 In try block (and after successful constraction)
 resources are controlled by std::auto_ptrs and dtor.

 Set pixel format.
 Resource - hDC, owned and freed by guard object.

Set event-handler. All events are passed to this object.

 Handle mouse crossing event.

Delegate call to the owner.

Delegate call to the owner.

Delegate call to the owner.

Delegate call to the owner.

Delegate call to the owner.

Delegate call to the owner.

Delegate call to the owner.
   if (!gVirtualX->IsCmdThread()) {
      gROOT->ProcessLineFast(Form("((TGLWidget *)0x%lx)->DoRedraw()", this));
      return;
   }