// @(#)root/gl:$Id$
// Author:  Richard Maunder  25/05/2005

/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#include "TGLViewer.h"
#include "TGLIncludes.h"
#include "TGLStopwatch.h"
#include "TGLRnrCtx.h"
#include "TGLSelectBuffer.h"
#include "TGLLightSet.h"
#include "TGLManipSet.h"
#include "TGLCameraOverlay.h"
#include "TGLAutoRotator.h"

#include "TGLScenePad.h"
#include "TGLLogicalShape.h"
#include "TGLPhysicalShape.h"
#include "TGLObject.h"
#include "TGLStopwatch.h"
#include "TBuffer3D.h"
#include "TBuffer3DTypes.h"

#include "TGLOutput.h"

#include "TROOT.h"
#include "TVirtualMutex.h"

#include "TVirtualPad.h" // Remove when pad removed - use signal
#include "TVirtualX.h"

#include "TMath.h"
#include "TColor.h"
#include "TError.h"
#include "TClass.h"
#include "TROOT.h"
#include "TEnv.h"

// For event type translation ExecuteEvent
#include "Buttons.h"
#include "GuiTypes.h"

#include "TVirtualGL.h"

#include "TGLWidget.h"
#include "TGLFBO.h"
#include "TGLViewerEditor.h"
#include "TGedEditor.h"
#include "TGLPShapeObj.h"

#include "KeySymbols.h"
#include "TContextMenu.h"
#include "TImage.h"

#include <stdexcept>

#ifndef GL_BGRA
#define GL_BGRA GL_BGRA_EXT
#endif

//==============================================================================
// TGLViewer
//==============================================================================

//______________________________________________________________________
//
// Base GL viewer object - used by both standalone and embedded (in pad)
// GL. Contains core viewer objects :
//
// GL scene - collection of main drawn objects - see TGLStdScene
// Cameras (fXyzzCamera) - ortho and perspective cameras - see TGLCamera
// Clipping (fClipXyzz) - collection of clip objects - see TGLClip
// Manipulators (fXyzzManip) - collection of manipulators - see TGLManip
//
// It maintains the current active draw styles, clipping object,
// manipulator, camera etc.
//
// TGLViewer is 'GUI free' in that it does not derive from any ROOT GUI
// TGFrame etc - see TGLSAViewer for this. However it contains GUI
// GUI style methods HandleButton() etc to which GUI events can be
// directed from standalone frame or embedding pad to perform
// interaction.
//
// Also, the TGLWidget needs to be created externally. It is not owned
// by the viewer.
//
// For embedded (pad) GL this viewer is created directly by plugin
// manager. For standalone the derived TGLSAViewer is.
//

ClassImp(TGLViewer);

TGLColorSet TGLViewer::fgDefaultColorSet;
Bool_t      TGLViewer::fgUseDefaultColorSetForNewViewers = kFALSE;

//______________________________________________________________________________
TGLViewer::TGLViewer(TVirtualPad * pad, Int_t x, Int_t y,
                     Int_t width, Int_t height) :
   fPad(pad),
   fContextMenu(0),
   fPerspectiveCameraXOZ(TGLVector3(-1.0, 0.0, 0.0), TGLVector3(0.0, 1.0, 0.0)), // XOZ floor
   fPerspectiveCameraYOZ(TGLVector3( 0.0,-1.0, 0.0), TGLVector3(1.0, 0.0, 0.0)), // YOZ floor
   fPerspectiveCameraXOY(TGLVector3(-1.0, 0.0, 0.0), TGLVector3(0.0, 0.0, 1.0)), // XOY floor
   fOrthoXOYCamera (TGLOrthoCamera::kXOY,  TGLVector3( 0.0, 0.0, 1.0), TGLVector3(0.0, 1.0, 0.0)), // Looking down  Z axis,  X horz, Y vert
   fOrthoXOZCamera (TGLOrthoCamera::kXOZ,  TGLVector3( 0.0,-1.0, 0.0), TGLVector3(0.0, 0.0, 1.0)), // Looking along Y axis,  X horz, Z vert
   fOrthoZOYCamera (TGLOrthoCamera::kZOY,  TGLVector3(-1.0, 0.0, 0.0), TGLVector3(0.0, 1.0, 0.0)), // Looking along X axis,  Z horz, Y vert
   fOrthoXnOYCamera(TGLOrthoCamera::kXnOY, TGLVector3( 0.0, 0.0,-1.0), TGLVector3(0.0, 1.0, 0.0)), // Looking along Z axis, -X horz, Y vert
   fOrthoXnOZCamera(TGLOrthoCamera::kXnOZ, TGLVector3( 0.0, 1.0, 0.0), TGLVector3(0.0, 0.0, 1.0)), // Looking down  Y axis, -X horz, Z vert
   fOrthoZnOYCamera(TGLOrthoCamera::kZnOY, TGLVector3( 1.0, 0.0, 0.0), TGLVector3(0.0, 1.0, 0.0)), // Looking down  X axis, -Z horz, Y vert
   fCurrentCamera(&fPerspectiveCameraXOZ),
   fAutoRotator(0),

   fStereo               (kFALSE),
   fStereoQuadBuf        (kFALSE),
   fStereoZeroParallax   (0.03f),
   fStereoEyeOffsetFac   (1.0f),
   fStereoFrustumAsymFac (1.0f),

   fLightSet          (0),
   fClipSet           (0),
   fSelectedPShapeRef (0),
   fCurrentOvlElm     (0),

   fEventHandler(0),
   fGedEditor(0),
   fPShapeWrap(0),
   fPushAction(kPushStd), fDragAction(kDragNone),
   fRedrawTimer(0),
   fMaxSceneDrawTimeHQ(5000),
   fMaxSceneDrawTimeLQ(100),
   fPointScale (1), fLineScale(1), fSmoothPoints(kFALSE), fSmoothLines(kFALSE),
   fAxesType(TGLUtil::kAxesNone),
   fAxesDepthTest(kTRUE),
   fReferenceOn(kFALSE),
   fReferencePos(0.0, 0.0, 0.0),
   fDrawCameraCenter(kFALSE),
   fCameraOverlay(0),
   fSmartRefresh(kFALSE),
   fDebugMode(kFALSE),
   fIsPrinting(kFALSE),
   fPictureFileName("viewer.jpg"),
   fFader(0),
   fGLWidget(0),
   fGLDevice(-1),
   fGLCtxId(0),
   fIgnoreSizesOnUpdate(kFALSE),
   fResetCamerasOnUpdate(kTRUE),
   fResetCamerasOnNextUpdate(kFALSE)
{
   // Construct the viewer object, with following arguments:
   //    'pad' - external pad viewer is bound to
   //    'x', 'y' - initial top left position
   //    'width', 'height' - initial width/height

   InitSecondaryObjects();

   SetViewport(x, y, width, height);
}

//______________________________________________________________________________
TGLViewer::TGLViewer(TVirtualPad * pad) :
   fPad(pad),
   fContextMenu(0),
   fPerspectiveCameraXOZ(TGLVector3(-1.0, 0.0, 0.0), TGLVector3(0.0, 1.0, 0.0)), // XOZ floor
   fPerspectiveCameraYOZ(TGLVector3( 0.0,-1.0, 0.0), TGLVector3(1.0, 0.0, 0.0)), // YOZ floor
   fPerspectiveCameraXOY(TGLVector3(-1.0, 0.0, 0.0), TGLVector3(0.0, 0.0, 1.0)), // XOY floor
   fOrthoXOYCamera (TGLOrthoCamera::kXOY,  TGLVector3( 0.0, 0.0, 1.0), TGLVector3(0.0, 1.0, 0.0)), // Looking down  Z axis,  X horz, Y vert
   fOrthoXOZCamera (TGLOrthoCamera::kXOZ,  TGLVector3( 0.0,-1.0, 0.0), TGLVector3(0.0, 0.0, 1.0)), // Looking along Y axis,  X horz, Z vert
   fOrthoZOYCamera (TGLOrthoCamera::kZOY,  TGLVector3(-1.0, 0.0, 0.0), TGLVector3(0.0, 1.0, 0.0)), // Looking along X axis,  Z horz, Y vert
   fOrthoXnOYCamera(TGLOrthoCamera::kXnOY, TGLVector3( 0.0, 0.0,-1.0), TGLVector3(0.0, 1.0, 0.0)), // Looking along Z axis, -X horz, Y vert
   fOrthoXnOZCamera(TGLOrthoCamera::kXnOZ, TGLVector3( 0.0, 1.0, 0.0), TGLVector3(0.0, 0.0, 1.0)), // Looking down  Y axis, -X horz, Z vert
   fOrthoZnOYCamera(TGLOrthoCamera::kZnOY, TGLVector3( 1.0, 0.0, 0.0), TGLVector3(0.0, 1.0, 0.0)), // Looking down  X axis, -Z horz, Y vert
   fCurrentCamera(&fPerspectiveCameraXOZ),
   fAutoRotator(0),

   fStereo               (kFALSE),
   fStereoQuadBuf        (kFALSE),
   fStereoZeroParallax   (0.03f),
   fStereoEyeOffsetFac   (1.0f),
   fStereoFrustumAsymFac (1.0f),

   fLightSet          (0),
   fClipSet           (0),
   fSelectedPShapeRef (0),
   fCurrentOvlElm     (0),

   fEventHandler(0),
   fGedEditor(0),
   fPShapeWrap(0),
   fPushAction(kPushStd), fDragAction(kDragNone),
   fRedrawTimer(0),
   fMaxSceneDrawTimeHQ(5000),
   fMaxSceneDrawTimeLQ(100),
   fPointScale (1), fLineScale(1), fSmoothPoints(kFALSE), fSmoothLines(kFALSE),
   fAxesType(TGLUtil::kAxesNone),
   fAxesDepthTest(kTRUE),
   fReferenceOn(kFALSE),
   fReferencePos(0.0, 0.0, 0.0),
   fDrawCameraCenter(kFALSE),
   fCameraOverlay(0),
   fSmartRefresh(kFALSE),
   fDebugMode(kFALSE),
   fIsPrinting(kFALSE),
   fPictureFileName("viewer.jpg"),
   fFader(0),
   fGLWidget(0),
   fGLDevice(fPad->GetGLDevice()),
   fGLCtxId(0),
   fIgnoreSizesOnUpdate(kFALSE),
   fResetCamerasOnUpdate(kTRUE),
   fResetCamerasOnNextUpdate(kFALSE)
{
   //gl-embedded viewer's ctor
   // Construct the viewer object, with following arguments:
   //    'pad' - external pad viewer is bound to
   //    'x', 'y' - initial top left position
   //    'width', 'height' - initial width/height

   InitSecondaryObjects();

   if (fGLDevice != -1) {
      // For the moment instantiate a fake context identity.
      fGLCtxId = new TGLContextIdentity;
      fGLCtxId->AddRef(0);
      Int_t viewport[4] = {0};
      gGLManager->ExtractViewport(fGLDevice, viewport);
      SetViewport(viewport[0], viewport[1], viewport[2], viewport[3]);
   }
}

//______________________________________________________________________________
void TGLViewer::InitSecondaryObjects()
{
   // Common initialization.

   fLightSet = new TGLLightSet;
   fClipSet  = new TGLClipSet;
   AddOverlayElement(fClipSet);

   fSelectedPShapeRef = new TGLManipSet;
   fSelectedPShapeRef->SetDrawBBox(kTRUE);
   AddOverlayElement(fSelectedPShapeRef);

   fPShapeWrap = new TGLPShapeObj(0, this);

   fLightColorSet.StdLightBackground();
   if (fgUseDefaultColorSetForNewViewers) {
      fRnrCtx->ChangeBaseColorSet(&fgDefaultColorSet);
   } else {
      if (fPad) {
         fRnrCtx->ChangeBaseColorSet(&fLightColorSet);
         fLightColorSet.Background().SetColor(fPad->GetFillColor());
         fLightColorSet.Foreground().SetColor(fPad->GetLineColor());
      } else {
         fRnrCtx->ChangeBaseColorSet(&fDarkColorSet);
      }
   }

   fCameraOverlay = new TGLCameraOverlay(kFALSE, kFALSE);
   AddOverlayElement(fCameraOverlay);

   fRedrawTimer = new TGLRedrawTimer(*this);
}

//______________________________________________________________________________
TGLViewer::~TGLViewer()
{
   // Destroy viewer object.

   delete fAutoRotator;

   delete fLightSet;
   // fClipSet, fSelectedPShapeRef and fCameraOverlay deleted via overlay.

   delete fContextMenu;
   delete fRedrawTimer;

   if (fEventHandler) {
      if (fGLWidget)
         fGLWidget->SetEventHandler(0);
      delete fEventHandler;
   }

   if (fPad)
      fPad->ReleaseViewer3D();
   if (fGLDevice != -1)
      fGLCtxId->Release(0);
}


//______________________________________________________________________________
void TGLViewer::PadPaint(TVirtualPad* pad)
{
   // Entry point for updating viewer contents via VirtualViewer3D
   // interface.
   // We search and forward the request to appropriate TGLScenePad.
   // If it is not found we create a new TGLScenePad so this can
   // potentially also be used for registration of new pads.

   TGLScenePad* scenepad = 0;
   for (SceneInfoList_i si = fScenes.begin(); si != fScenes.end(); ++si)
   {
      scenepad = dynamic_cast<TGLScenePad*>((*si)->GetScene());
      if (scenepad && scenepad->GetPad() == pad)
         break;
      scenepad = 0;
   }
   if (scenepad == 0)
   {
      scenepad = new TGLScenePad(pad);
      AddScene(scenepad);
   }

   scenepad->PadPaintFromViewer(this);

   PostSceneBuildSetup(fResetCamerasOnNextUpdate || fResetCamerasOnUpdate);
   fResetCamerasOnNextUpdate = kFALSE;

   RequestDraw();
}


/**************************************************************************/
/**************************************************************************/

//______________________________________________________________________________
void TGLViewer::UpdateScene(Bool_t redraw)
{
   // Force update of pad-scenes. Eventually this could be generalized
   // to all scene-types via a virtual function in TGLSceneBase.

   // Cancel any pending redraw timer.
   fRedrawTimer->Stop();

   for (SceneInfoList_i si = fScenes.begin(); si != fScenes.end(); ++si)
   {
      TGLScenePad* scenepad = dynamic_cast<TGLScenePad*>((*si)->GetScene());
      if (scenepad)
         scenepad->PadPaintFromViewer(this);
   }

   PostSceneBuildSetup(fResetCamerasOnNextUpdate || fResetCamerasOnUpdate);
   fResetCamerasOnNextUpdate = kFALSE;

   if (redraw)
      RequestDraw();
}

//______________________________________________________________________________
void TGLViewer::ResetCurrentCamera()
{
   // Resets position/rotation of current camera to default values.

   MergeSceneBBoxes(fOverallBoundingBox);
   CurrentCamera().Setup(fOverallBoundingBox, kTRUE);
}

//______________________________________________________________________________
void TGLViewer::SetupCameras(Bool_t reset)
{
   // Setup cameras for current bounding box.

   if (IsLocked()) {
      Error("TGLViewer::SetupCameras", "expected kUnlocked, found %s", LockName(CurrentLock()));
      return;
   }

   // Setup cameras if scene box is not empty
   const TGLBoundingBox & box = fOverallBoundingBox;
   if (!box.IsEmpty()) {
      fPerspectiveCameraYOZ.Setup(box, reset);
      fPerspectiveCameraXOZ.Setup(box, reset);
      fPerspectiveCameraXOY.Setup(box, reset);
      fOrthoXOYCamera.Setup(box, reset);
      fOrthoXOZCamera.Setup(box, reset);
      fOrthoZOYCamera.Setup(box, reset);
      fOrthoXnOYCamera.Setup(box, reset);
      fOrthoXnOZCamera.Setup(box, reset);
      fOrthoZnOYCamera.Setup(box, reset);
   }
}

//______________________________________________________________________________
void TGLViewer::PostSceneBuildSetup(Bool_t resetCameras)
{
   // Perform post scene-build setup.

   MergeSceneBBoxes(fOverallBoundingBox);
   SetupCameras(resetCameras);

   // Set default reference to center
   fReferencePos.Set(fOverallBoundingBox.Center());
   RefreshPadEditor(this);
}


/**************************************************************************/
/**************************************************************************/

//______________________________________________________________________________
void TGLViewer::InitGL()
{
   // Initialise GL state.

   glEnable(GL_LIGHTING);
   glEnable(GL_DEPTH_TEST);
   glEnable(GL_CULL_FACE);
   glCullFace(GL_BACK);
   glClearColor(0.f, 0.f, 0.f, 0.f);
   glClearDepth(1.0);
   glColorMaterial(GL_FRONT_AND_BACK, GL_DIFFUSE);
   glEnable(GL_COLOR_MATERIAL);
   glMaterialf(GL_BACK, GL_SHININESS, 0.0);
   glPolygonMode(GL_FRONT, GL_FILL);
   glDisable(GL_BLEND);

   glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE);
   Float_t lmodelAmb[] = {0.5f, 0.5f, 1.f, 1.f};
   glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodelAmb);
   glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_FALSE);

   glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
   glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);

   TGLUtil::CheckError("TGLViewer::InitGL");
}

//______________________________________________________________________________
void TGLViewer::RequestDraw(Short_t LODInput)
{
   // Post request for redraw of viewer at level of detail 'LOD'
   // Request is directed via cross thread gVirtualGL object.

   fRedrawTimer->Stop();
   // Ignore request if GL window or context not yet availible or shown.
   if ((!fGLWidget && fGLDevice == -1) || (fGLWidget && !fGLWidget->IsMapped()))
   {
      return;
   }

   // Take scene draw lock - to be revisited
   if ( ! TakeLock(kDrawLock)) {
      // If taking drawlock fails the previous draw is still in progress
      // set timer to do this one later
      if (gDebug>3) {
         Info("TGLViewer::RequestDraw", "viewer locked - requesting another draw.");
      }
      fRedrawTimer->RequestDraw(100, LODInput);
      return;
   }
   fLOD = LODInput;

   if (!gVirtualX->IsCmdThread())
      gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoDraw()", (ULong_t)this));
   else
      DoDraw();
}

//______________________________________________________________________________
void TGLViewer::SetupClipObject()
{
   // Setup clip-object. Protected virtual method.

   if (GetClipAutoUpdate())
   {
      fClipSet->SetupCurrentClip(fOverallBoundingBox);
   }
   else
   {
      fClipSet->SetupCurrentClipIfInvalid(fOverallBoundingBox);
   }
}
//______________________________________________________________________________
void TGLViewer::PreRender()
{
   // Initialize objects that influence rendering.
   // Called before every render.

   fCamera = fCurrentCamera;
   fClip   = fClipSet->GetCurrentClip();
   if (fGLDevice != -1)
   {
      fRnrCtx->SetGLCtxIdentity(fGLCtxId);
      fGLCtxId->DeleteGLResources();
   }

   TGLUtil::SetPointSizeScale(fPointScale * fRnrCtx->GetRenderScale());
   TGLUtil::SetLineWidthScale(fLineScale  * fRnrCtx->GetRenderScale());

   if (fSmoothPoints) glEnable(GL_POINT_SMOOTH); else glDisable(GL_POINT_SMOOTH);
   if (fSmoothLines)  glEnable(GL_LINE_SMOOTH);  else glDisable(GL_LINE_SMOOTH);
   if (fSmoothPoints || fSmoothLines)
   {
      glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
      glEnable(GL_BLEND);
   }
   else
   {
      glDisable(GL_BLEND);
   }

   TGLViewerBase::PreRender();

   // Setup lighting
   fLightSet->StdSetupLights(fOverallBoundingBox, *fCamera, fDebugMode);
}

//______________________________________________________________________________
void TGLViewer::Render()
{
   // Normal rendering, used by mono and stereo rendering.

   TGLViewerBase::Render();

   DrawGuides();
   RenderOverlay(TGLOverlayElement::kAllVisible, kFALSE);

   if ( ! fRnrCtx->Selection())
   {
      RenderSelectedForHighlight();
   }

   glClear(GL_DEPTH_BUFFER_BIT);
   DrawDebugInfo();
}

//______________________________________________________________________________
void TGLViewer::PostRender()
{
   // Restore state set in PreRender().
   // Called after every render.

   TGLViewerBase::PostRender();

   TGLUtil::SetPointSizeScale(1);
   TGLUtil::SetLineWidthScale(1);
}

//______________________________________________________________________________
void TGLViewer::DoDraw(Bool_t swap_buffers)
{
   // Draw out the viewer.

   // Locking mainly for Win32 multi thread safety - but no harm in all using it
   // During normal draws a draw lock is taken in other thread (Win32) in RequestDraw()
   // to ensure thread safety. For PrintObjects repeated Draw() calls are made.
   // If no draw lock taken get one now.

   R__LOCKGUARD2(gROOTMutex);

   fRedrawTimer->Stop();

   if (CurrentLock() != kDrawLock) {
      if ( ! TakeLock(kDrawLock)) {
         Error("TGLViewer::DoDraw", "viewer is %s", LockName(CurrentLock()));
         return;
      }
   }

   TUnlocker ulck(this);

   if (fGLDevice == -1 && (fViewport.Width() <= 1 || fViewport.Height() <= 1)) {
      if (gDebug > 2) {
         Info("TGLViewer::DoDraw()", "zero surface area, draw skipped.");
      }
      return;
   }

   if (fGLDevice != -1) {
      Int_t viewport[4] = {};
      gGLManager->ExtractViewport(fGLDevice, viewport);
      SetViewport(viewport[0], viewport[1], viewport[2], viewport[3]);
   }

   TGLStopwatch timer;
   if (gDebug>2) {
      timer.Start();
   }

   // Setup scene draw time
   fRnrCtx->SetRenderTimeOut(fLOD == TGLRnrCtx::kLODHigh ?
                             fMaxSceneDrawTimeHQ :
                             fMaxSceneDrawTimeLQ);

   if (fStereo && fCurrentCamera->IsPerspective() && !fRnrCtx->GetGrabImage() &&
       !fIsPrinting)
   {
      DoDrawStereo(swap_buffers);
   }
   else
   {
      DoDrawMono(swap_buffers);
   }

   ReleaseLock(kDrawLock);

   if (gDebug>2) {
      Info("TGLViewer::DoDraw()", "Took %f msec", timer.End());
   }

   // Check if further redraws are needed and schedule them.

   if (CurrentCamera().UpdateInterest(kFALSE)) {
      // Reset major view-dependant cache.
      ResetSceneInfos();
      fRedrawTimer->RequestDraw(0, fLOD);
   }

   if (fLOD != TGLRnrCtx::kLODHigh &&
       (fDragAction < kDragCameraRotate || fDragAction > kDragCameraDolly))
   {
      // Request final draw pass.
      fRedrawTimer->RequestDraw(100, TGLRnrCtx::kLODHigh);
   }
}

//______________________________________________________________________________
void TGLViewer::DoDrawMono(Bool_t swap_buffers)
{
   // Draw out in monoscopic mode.

   MakeCurrent();

   if (!fIsPrinting) PreDraw();
   PreRender();

   fRnrCtx->StartStopwatch();
   if (fFader < 1)
   {
      Render();
   }
   fRnrCtx->StopStopwatch();

   PostRender();

   if (fFader > 0)
   {
      FadeView(fFader);
   }

   PostDraw();

   if (swap_buffers)
   {
      SwapBuffers();
   }
}

//______________________________________________________________________________
void TGLViewer::DoDrawStereo(Bool_t swap_buffers)
{
   // Draw out in stereoscopic mode.

   TGLPerspectiveCamera &c = *dynamic_cast<TGLPerspectiveCamera*>(fCurrentCamera);

   Float_t gl_near, gl_far, zero_p_dist;
   Float_t h_half, w_half;
   Float_t x_len_at_zero_parallax;
   Float_t stereo_offset;
   Float_t frustum_asym;

   MakeCurrent();

   // Draw left
   if (fStereoQuadBuf)
   {
      glDrawBuffer(GL_BACK_LEFT);
   }
   else
   {
      glScissor(0, 0, fViewport.Width(), fViewport.Height());
      glEnable(GL_SCISSOR_TEST);
   }
   PreDraw();
   PreRender();

   gl_near = c.GetNearClip();
   gl_far  = c.GetFarClip();
   zero_p_dist = gl_near + fStereoZeroParallax*(gl_far-gl_near);

   h_half = TMath::Tan(0.5*TMath::DegToRad()*c.GetFOV()) * gl_near;
   w_half = h_half * fViewport.Aspect();

   x_len_at_zero_parallax = 2.0f * w_half * zero_p_dist / gl_near;
   stereo_offset = 0.035f * x_len_at_zero_parallax * fStereoEyeOffsetFac;

   frustum_asym = stereo_offset * gl_near / zero_p_dist * fStereoFrustumAsymFac;

   TGLMatrix  abs_trans(c.RefCamBase());
   abs_trans *= c.RefCamTrans();
   TGLVector3 left_vec = abs_trans.GetBaseVec(2);

   glTranslatef(stereo_offset*left_vec[0], stereo_offset*left_vec[1], stereo_offset*left_vec[2]);

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glFrustum(-w_half + frustum_asym, w_half + frustum_asym,
             -h_half, h_half, gl_near, gl_far);
   glMatrixMode(GL_MODELVIEW);

   fRnrCtx->StartStopwatch();
   if (fFader < 1)
   {
      Render();
   }
   fRnrCtx->StopStopwatch();

   PostRender();

   if (fFader > 0)
   {
      FadeView(fFader);
   }
   PostDraw();

   // Draw right
   if (fStereoQuadBuf)
   {
      glDrawBuffer(GL_BACK_RIGHT);
   }
   else
   {
      glScissor(fViewport.Width(), 0, fViewport.Width(), fViewport.Height());
   }
   PreDraw();
   PreRender();
   if ( ! fStereoQuadBuf)
   {
      glViewport(fViewport.Width(), 0, fViewport.Width(), fViewport.Height());
   }

   glTranslatef(-stereo_offset*left_vec[0], -stereo_offset*left_vec[1], -stereo_offset*left_vec[2]);

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glFrustum(-w_half - frustum_asym, w_half - frustum_asym,
             -h_half, h_half, gl_near, gl_far);
   glMatrixMode(GL_MODELVIEW);

   fRnrCtx->StartStopwatch();
   if (fFader < 1)
   {
      Render();
   }
   fRnrCtx->StopStopwatch();

   PostRender();

   if (fFader > 0)
   {
      FadeView(fFader);
   }
   PostDraw();

   // End
   if (swap_buffers)
   {
      SwapBuffers();
   }

   if (fStereoQuadBuf)
   {
      glDrawBuffer(GL_BACK);
   }
   else
   {
      glDisable(GL_SCISSOR_TEST);
      glViewport(0, 0, fViewport.Width(), fViewport.Height());
   }
}

//______________________________________________________________________________
Bool_t TGLViewer::SavePicture()
{
   // Save current image using the default file name which can be set
   // via SetPictureFileName() and defaults to "viewer.jpg".
   // Really useful for the files ending with 'gif+'.

   return SavePicture(fPictureFileName);
}

//______________________________________________________________________________
Bool_t TGLViewer::SavePicture(const TString &fileName)
{
   // Save current image in various formats (gif, gif+, jpg, png, eps, pdf).
   // 'gif+' will append image to an existng file (animated gif).
   // 'eps' and 'pdf' do not fully support transparency and texturing.
   // The viewer window most be fully contained within the desktop but
   // can be covered by other windows.
   // Returns false if something obvious goes wrong, true otherwise.
   //
   // The mage is saved using a frame-buffer object if the GL implementation
   // claims to support it -- this claim is not always true, especially when
   // running over ssh with drastically different GL implementations on the
   // client and server sides. Set this in .rootrc to enforce creation of
   // pictures using the back-buffer:
   //   OpenGL.SavePicturesViaFBO: off

   if (fileName.EndsWith(".eps"))
   {
      return TGLOutput::Capture(*this, TGLOutput::kEPS_BSP, fileName.Data());
   }
   else if (fileName.EndsWith(".pdf"))
   {
      return TGLOutput::Capture(*this, TGLOutput::kPDF_BSP, fileName.Data());
   }
   else
   {
      if (GLEW_EXT_framebuffer_object && gEnv->GetValue("OpenGL.SavePicturesViaFBO", 1))
      {
         return SavePictureUsingFBO(fileName, fViewport.Width(), fViewport.Height(), kFALSE);
      }
      else
      {
         return SavePictureUsingBB(fileName);
      }
   }
}

//______________________________________________________________________________
Bool_t TGLViewer::SavePictureUsingBB(const TString &fileName)
{
   // Save current image in various formats (gif, gif+, jpg, png).
   // 'gif+' will append image to an existng file (animated gif).
   // Back-Buffer is used for capturing of the image.
   // The viewer window most be fully contained within the desktop but
   // can be covered by other windows.
   // Returns false if something obvious goes wrong, true otherwise.

   static const TString eh("TGLViewer::SavePictureUsingBB");

   if (! fileName.EndsWith(".gif") && ! fileName.Contains(".gif+") &&
       ! fileName.EndsWith(".jpg") && ! fileName.EndsWith(".png"))
   {
      Warning(eh, "file %s cannot be saved with this extension.", fileName.Data());
      return kFALSE;
   }

   if ( ! TakeLock(kDrawLock)) {
      Error(eh, "viewer locked - try later.");
      return kFALSE;
   }

   TUnlocker ulck(this);

   fLOD = TGLRnrCtx::kLODHigh;
   fRnrCtx->SetGrabImage(kTRUE);

   if (!gVirtualX->IsCmdThread())
      gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoDraw(kFALSE)", (ULong_t)this));
   else
      DoDraw(kFALSE);

   fRnrCtx->SetGrabImage(kFALSE);

   glReadBuffer(GL_BACK);

   UChar_t* xx = new UChar_t[4 * fViewport.Width() * fViewport.Height()];
   glPixelStorei(GL_PACK_ALIGNMENT, 1);
   glReadPixels(0, 0, fViewport.Width(), fViewport.Height(),
                GL_BGRA, GL_UNSIGNED_BYTE, xx);

   std::auto_ptr<TImage> image(TImage::Create());
   image->FromGLBuffer(xx, fViewport.Width(), fViewport.Height());
   image->WriteImage(fileName);

   delete [] xx;

   return kTRUE;
}

//______________________________________________________________________________
Bool_t TGLViewer::SavePictureUsingFBO(const TString &fileName, Int_t w, Int_t h,
                                      Float_t pixel_object_scale)
{
   // Save current image in various formats (gif, gif+, jpg, png).
   // 'gif+' will append image to an existng file (animated gif).
   // Frame-Buffer-Object is used for capturing of the image - OpenGL
   // 1.5 is required.
   // The viewer window does not have to be visible at all.
   // Returns false if something obvious goes wrong, true otherwise.
   //
   // pixel_object_scale is used to scale (as much as possible) the
   // objects whose representation size is pixel based (point-sizes,
   // line-widths, bitmap/pixmap font-sizes).
   // If set to 0 (default) no scaling is applied.

   static const TString eh("TGLViewer::SavePictureUsingFBO");

   if (! fileName.EndsWith(".gif") && ! fileName.Contains(".gif+") &&
       ! fileName.EndsWith(".jpg") && ! fileName.EndsWith(".png"))
   {
      Warning(eh, "file %s cannot be saved with this extension.", fileName.Data());
      return kFALSE;
   }

   if ( ! TakeLock(kDrawLock)) {
      Error(eh, "viewer locked - try later.");
      return kFALSE;
   }

   TUnlocker ulck(this);

   MakeCurrent();

   TGLFBO *fbo = new TGLFBO();
   try
   {
      fbo->Init(w, h, fGLWidget->GetPixelFormat()->GetSamples());
   }
   catch (std::runtime_error& exc)
   {
      Error(eh, "%s",exc.what());
      if (gEnv->GetValue("OpenGL.SavePictureFallbackToBB", 1)) {
         Info(eh, "Falling back to saving image via back-buffer. Window must be fully visible.");
         if (w != fViewport.Width() || h != fViewport.Height())
            Warning(eh, "Back-buffer does not support image scaling, window size will be used.");
         return SavePictureUsingBB(fileName);
      } else {
         return kFALSE;
      }
   }

   TGLRect old_vp(fViewport);
   SetViewport(0, 0, w, h);

   Float_t old_scale = 1;
   if (pixel_object_scale != 0)
   {
      old_scale = fRnrCtx->GetRenderScale();
      fRnrCtx->SetRenderScale(old_scale * pixel_object_scale);
   }

   fbo->Bind();

   fLOD = TGLRnrCtx::kLODHigh;
   fRnrCtx->SetGrabImage(kTRUE);

   if (!gVirtualX->IsCmdThread())
      gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoDraw(kFALSE)", (ULong_t)this));
   else
      DoDraw(kFALSE);

   fRnrCtx->SetGrabImage(kFALSE);

   fbo->Unbind();

   fbo->SetAsReadBuffer();

   UChar_t* xx = new UChar_t[4 * fViewport.Width() * fViewport.Height()];
   glPixelStorei(GL_PACK_ALIGNMENT, 1);
   glReadPixels(0, 0, fViewport.Width(), fViewport.Height(),
                GL_BGRA, GL_UNSIGNED_BYTE, xx);

   std::auto_ptr<TImage> image(TImage::Create());
   image->FromGLBuffer(xx, fViewport.Width(), fViewport.Height());
   image->WriteImage(fileName);

   delete [] xx;

   delete fbo;

   if (pixel_object_scale != 0)
   {
      fRnrCtx->SetRenderScale(old_scale);
   }

   SetViewport(old_vp);

   return kTRUE;
}

//______________________________________________________________________________
TImage* TGLViewer::GetPictureUsingBB()
{
    // Returns current image.
    // Back-Buffer is used for capturing of the image.
    // The viewer window most be fully contained within the desktop but
    // can be covered by other windows.

    static const TString eh("TGLViewer::GetPictureUsingBB");

    if ( ! TakeLock(kDrawLock)) {
        Error(eh, "viewer locked - try later.");
        return NULL;
    }

    TUnlocker ulck(this);

    fLOD = TGLRnrCtx::kLODHigh;
    fRnrCtx->SetGrabImage(kTRUE);

    if (!gVirtualX->IsCmdThread())
        gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoDraw(kFALSE)", (ULong_t)this));
    else
        DoDraw(kFALSE);

    fRnrCtx->SetGrabImage(kFALSE);

    glReadBuffer(GL_BACK);

    UChar_t* xx = new UChar_t[4 * fViewport.Width() * fViewport.Height()];
    glPixelStorei(GL_PACK_ALIGNMENT, 1);
    glReadPixels(0, 0, fViewport.Width(), fViewport.Height(),
                 GL_BGRA, GL_UNSIGNED_BYTE, xx);

    TImage *image(TImage::Create());
    image->FromGLBuffer(xx, fViewport.Width(), fViewport.Height());

    delete [] xx;

    return image;
}

//______________________________________________________________________________
TImage* TGLViewer::GetPictureUsingFBO(Int_t w, Int_t h,Float_t pixel_object_scale)
{
    // Returns current image.
    // Frame-Buffer-Object is used for capturing of the image - OpenGL
    // 1.5 is required.
    // The viewer window does not have to be visible at all.
    //
    // pixel_object_scale is used to scale (as much as possible) the
    // objects whose representation size is pixel based (point-sizes,
    // line-widths, bitmap/pixmap font-sizes).
    // If set to 0 (default) no scaling is applied.

    static const TString eh("TGLViewer::GetPictureUsingFBO");

    if ( ! TakeLock(kDrawLock)) {
        Error(eh, "viewer locked - try later.");
        return NULL;
    }

    TUnlocker ulck(this);

    MakeCurrent();

    TGLFBO *fbo = new TGLFBO();
    try
    {
        fbo->Init(w, h, fGLWidget->GetPixelFormat()->GetSamples());
    }
    catch (std::runtime_error& exc)
    {
        Error(eh, "%s",exc.what());
        if (gEnv->GetValue("OpenGL.GetPictureFallbackToBB", 1)) {
            Info(eh, "Falling back to saving image via back-buffer. Window must be fully visible.");
            if (w != fViewport.Width() || h != fViewport.Height())
                Warning(eh, "Back-buffer does not support image scaling, window size will be used.");
            return GetPictureUsingBB();
        } else {
            return NULL;
        }
    }

    TGLRect old_vp(fViewport);
    SetViewport(0, 0, w, h);

    Float_t old_scale = 1;
    if (pixel_object_scale != 0)
    {
        old_scale = fRnrCtx->GetRenderScale();
        fRnrCtx->SetRenderScale(old_scale * pixel_object_scale);
    }

    fbo->Bind();

    fLOD = TGLRnrCtx::kLODHigh;
    fRnrCtx->SetGrabImage(kTRUE);

    if (!gVirtualX->IsCmdThread())
        gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoDraw(kFALSE)", (ULong_t)this));
    else
        DoDraw(kFALSE);

    fRnrCtx->SetGrabImage(kFALSE);

    fbo->Unbind();

    fbo->SetAsReadBuffer();

    UChar_t* xx = new UChar_t[4 * fViewport.Width() * fViewport.Height()];
    glPixelStorei(GL_PACK_ALIGNMENT, 1);
    glReadPixels(0, 0, fViewport.Width(), fViewport.Height(),
                 GL_BGRA, GL_UNSIGNED_BYTE, xx);

    TImage *image(TImage::Create());
    image->FromGLBuffer(xx, fViewport.Width(), fViewport.Height());

    delete [] xx;
    delete fbo;

    return image;
}


//______________________________________________________________________________
Bool_t TGLViewer::SavePictureWidth(const TString &fileName, Int_t width,
                                   Bool_t pixel_object_scale)
{
   // Save picture with given width (height scaled proportinally).
   // If pixel_object_scale is true (default), the corresponding
   // scaling gets calculated from the current window size.

   Float_t scale  = Float_t(width) / fViewport.Width();
   Int_t   height = TMath::Nint(scale*fViewport.Height());

   return SavePictureUsingFBO(fileName, width, height, pixel_object_scale ? scale : 0);
}

//______________________________________________________________________________
Bool_t TGLViewer::SavePictureHeight(const TString &fileName, Int_t height,
                                    Bool_t pixel_object_scale)
{
   // Save picture with given height (width scaled proportinally).
   // If pixel_object_scale is true (default), the corresponding
   // scaling gets calculated from the current window size.

   Float_t scale = Float_t(height) / fViewport.Height();
   Int_t   width = TMath::Nint(scale*fViewport.Width());

   return SavePictureUsingFBO(fileName, width, height, pixel_object_scale ? scale : 0);
}

//______________________________________________________________________________
Bool_t TGLViewer::SavePictureScale (const TString &fileName, Float_t scale,
                                    Bool_t pixel_object_scale)
{
   // Save picture with given scale to current window size.
   // If pixel_object_scale is true (default), the same scaling is
   // used.

   Int_t w = TMath::Nint(scale*fViewport.Width());
   Int_t h = TMath::Nint(scale*fViewport.Height());

   return SavePictureUsingFBO(fileName, w, h, pixel_object_scale ? scale : 0);
}

//______________________________________________________________________________
void TGLViewer::DrawGuides()
{
   // Draw reference marker and coordinate axes.

   Bool_t disabled = kFALSE;
   if (fReferenceOn)
   {
      glDisable(GL_DEPTH_TEST);
      TGLUtil::DrawReferenceMarker(*fCamera, fReferencePos);
      disabled = kTRUE;
   }
   if (fDrawCameraCenter)
   {
      glDisable(GL_DEPTH_TEST);
      Float_t radius = fCamera->ViewportDeltaToWorld(TGLVertex3(fCamera->GetCenterVec()), 3, 3).Mag();
      const UChar_t rgba[4] = { 0, 255, 255, 255 };
      TGLUtil::DrawSphere(fCamera->GetCenterVec(), radius, rgba);
      disabled = kTRUE;
   }
   if (fAxesDepthTest && disabled)
   {
      glEnable(GL_DEPTH_TEST);
      disabled = kFALSE;
   }
   else if (fAxesDepthTest == kFALSE && disabled == kFALSE)
   {
      glDisable(GL_DEPTH_TEST);
      disabled = kTRUE;
   }
   TGLUtil::DrawSimpleAxes(*fCamera, fOverallBoundingBox, fAxesType);
   if (disabled)
      glEnable(GL_DEPTH_TEST);
}

//______________________________________________________________________________
void TGLViewer::DrawDebugInfo()
{
   // If in debug mode draw camera aids and overall bounding box.

   if (fDebugMode)
   {
      glDisable(GL_LIGHTING);
      CurrentCamera().DrawDebugAids();

      // Green scene bounding box
      glColor3d(0.0, 1.0, 0.0);
      fOverallBoundingBox.Draw();

      // Scene bounding box center sphere (green) and
      glDisable(GL_DEPTH_TEST);
      Double_t size = fOverallBoundingBox.Extents().Mag() / 200.0;
      TGLUtil::DrawSphere(TGLVertex3(0.0, 0.0, 0.0), size, TGLUtil::fgWhite);
      const TGLVertex3 & center = fOverallBoundingBox.Center();
      TGLUtil::DrawSphere(center, size, TGLUtil::fgGreen);
      glEnable(GL_DEPTH_TEST);

      glEnable(GL_LIGHTING);
   }
}

//______________________________________________________________________________
void TGLViewer::PreDraw()
{
   // Perform GL work which must be done before each draw.

   InitGL();

   // For embedded gl clear color must be pad's background color.
   {
      Color_t ci = (fGLDevice != -1) ? gPad->GetFillColor() : fRnrCtx->ColorSet().Background().GetColorIndex();
      TColor *color = gROOT->GetColor(ci);
      Float_t rgb[3];
      if (color)
         color->GetRGB(rgb[0], rgb[1], rgb[2]);
      else
         rgb[0] = rgb[1] = rgb[2] = 0.0f;

      glClearColor(rgb[0], rgb[1], rgb[2], 0.0f);
   }

   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

   TGLUtil::CheckError("TGLViewer::PreDraw");
}

//______________________________________________________________________________
void TGLViewer::PostDraw()
{
   // Perform GL work which must be done after each draw.

   glFlush();
   TGLUtil::CheckError("TGLViewer::PostDraw");
}

//______________________________________________________________________________
void TGLViewer::FadeView(Float_t alpha)
{
   // Draw a rectangle (background color and given alpha) across the
   // whole viewport.

   static const Float_t z = -1.0f;

   glMatrixMode(GL_PROJECTION); glPushMatrix(); glLoadIdentity();
   glMatrixMode(GL_MODELVIEW);  glPushMatrix(); glLoadIdentity();

   {
      TGLCapabilitySwitch blend(GL_BLEND,    kTRUE);
      TGLCapabilitySwitch light(GL_LIGHTING, kFALSE);
      glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
      TGLUtil::ColorAlpha(fRnrCtx->ColorSet().Background(), alpha);
      glBegin(GL_QUADS);
      glVertex3f(-1, -1, z);  glVertex3f( 1, -1, z);
      glVertex3f( 1,  1, z);  glVertex3f(-1,  1, z);
      glEnd();
   }

   glMatrixMode(GL_PROJECTION); glPopMatrix();
   glMatrixMode(GL_MODELVIEW);  glPopMatrix();
}

//______________________________________________________________________________
void TGLViewer::MakeCurrent() const
{
   // Make GL context current
   if (fGLDevice == -1)
      fGLWidget->MakeCurrent();
   else
      gGLManager->MakeCurrent(fGLDevice);
}

//______________________________________________________________________________
void TGLViewer::SwapBuffers() const
{
   // Swap GL buffers
   if ( ! IsDrawOrSelectLock()) {
      Error("TGLViewer::SwapBuffers", "viewer is %s", LockName(CurrentLock()));
   }
   if (fGLDevice == -1)
      fGLWidget->SwapBuffers();
   else {
      gGLManager->ReadGLBuffer(fGLDevice);
      gGLManager->Flush(fGLDevice);
      gGLManager->MarkForDirectCopy(fGLDevice, kFALSE);
   }
}

//______________________________________________________________________________
Bool_t TGLViewer::RequestSelect(Int_t x, Int_t y)
{
   // Post request for selection render pass viewer, picking objects
   // around the window point (x,y).

   // Take select lock on scene immediately we enter here - it is released
   // in the other (drawing) thread - see TGLViewer::DoSelect()

   if ( ! TakeLock(kSelectLock)) {
      return kFALSE;
   }

   if (!gVirtualX->IsCmdThread())
      return Bool_t(gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoSelect(%d, %d)", (ULong_t)this, x, y)));
   else
      return DoSelect(x, y);
}

//______________________________________________________________________________
Bool_t TGLViewer::DoSelect(Int_t x, Int_t y)
{
   // Perform GL selection, picking objects overlapping WINDOW
   // area described by 'rect'. Return kTRUE if selection should be
   // changed, kFALSE otherwise.
   // Select lock should already been taken in other thread in
   // TGLViewer::ReqSelect().

   R__LOCKGUARD2(gROOTMutex);

   if (CurrentLock() != kSelectLock) {
      Error("TGLViewer::DoSelect", "expected kSelectLock, found %s", LockName(CurrentLock()));
      return kFALSE;
   }

   TGLUtil::PointToViewport(x, y);

   TUnlocker ulck(this);

   MakeCurrent();

   fRnrCtx->BeginSelection(x, y, TGLUtil::GetPickingRadius());
   glRenderMode(GL_SELECT);

   PreRender();
   TGLViewerBase::Render();
   PostRender();

   Int_t nHits = glRenderMode(GL_RENDER);
   fRnrCtx->EndSelection(nHits);

   // Process selection.
   if (gDebug > 0) Info("TGLViewer::DoSelect", "Primary select nHits=%d.", nHits);

   if (nHits > 0)
   {
      Int_t idx = 0;
      if (FindClosestRecord(fSelRec, idx))
      {
         if (fSelRec.GetTransparent() && fRnrCtx->SelectTransparents() != TGLRnrCtx::kIfClosest)
         {
            TGLSelectRecord opaque;
            if (FindClosestOpaqueRecord(opaque, ++idx))
               fSelRec = opaque;
            else if (fRnrCtx->SelectTransparents() == TGLRnrCtx::kNever)
               fSelRec.Reset();
         }
         if (gDebug > 1) fSelRec.Print();
      }
   } else {
      fSelRec.Reset();
   }

   ReleaseLock(kSelectLock);
   return ! TGLSelectRecord::AreSameSelectionWise(fSelRec, fCurrentSelRec);
}

//______________________________________________________________________________
Bool_t TGLViewer::RequestSecondarySelect(Int_t x, Int_t y)
{
   // Request secondary select.

   if ( ! TakeLock(kSelectLock)) {
      return kFALSE;
   }

   if (!gVirtualX->IsCmdThread())
      return Bool_t(gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoSecondarySelect(%d, %d)", (ULong_t)this, x, y)));
   else
      return DoSecondarySelect(x, y);
}

//______________________________________________________________________________
Bool_t TGLViewer::DoSecondarySelect(Int_t x, Int_t y)
{
   // Secondary selection.

   R__LOCKGUARD2(gROOTMutex);

   if (CurrentLock() != kSelectLock) {
      Error("TGLViewer::DoSecondarySelect", "expected kSelectLock, found %s", LockName(CurrentLock()));
      return kFALSE;
   }

   TGLUtil::PointToViewport(x, y);

   TUnlocker ulck(this);

   if (! fSelRec.GetSceneInfo() || ! fSelRec.GetPhysShape() ||
       ! fSelRec.GetLogShape()->SupportsSecondarySelect())
   {
      if (gDebug > 0)
         Info("TGLViewer::SecondarySelect", "Skipping secondary selection "
              "(sinfo=0x%lx, pshape=0x%lx).\n",
              (Long_t)fSelRec.GetSceneInfo(), (Long_t)fSelRec.GetPhysShape());
      fSecSelRec.Reset();
      return kFALSE;
   }

   MakeCurrent();

   TGLSceneInfo*    sinfo = fSelRec.GetSceneInfo();
   TGLSceneBase*    scene = sinfo->GetScene();
   TGLPhysicalShape* pshp = fSelRec.GetPhysShape();

   SceneInfoList_t foo;
   foo.push_back(sinfo);
   fScenes.swap(foo);
   fRnrCtx->BeginSelection(x, y, TGLUtil::GetPickingRadius());
   fRnrCtx->SetSecSelection(kTRUE);
   glRenderMode(GL_SELECT);

   PreRender();
   fRnrCtx->SetSceneInfo(sinfo);
   scene->PreRender(*fRnrCtx);
   fRnrCtx->SetDrawPass(TGLRnrCtx::kPassFill);
   fRnrCtx->SetShapeLOD(TGLRnrCtx::kLODHigh);
   glPushName(pshp->ID());
   // !!! Hack: does not use clipping and proper draw-pass settings.
   pshp->Draw(*fRnrCtx);
   glPopName();
   scene->PostRender(*fRnrCtx);
   fRnrCtx->SetSceneInfo(0);
   PostRender();

   Int_t nSecHits = glRenderMode(GL_RENDER);
   fRnrCtx->EndSelection(nSecHits);
   fScenes.swap(foo);

   if (gDebug > 0) Info("TGLViewer::DoSelect", "Secondary select nSecHits=%d.", nSecHits);

   ReleaseLock(kSelectLock);

   if (nSecHits > 0)
   {
      fSecSelRec = fSelRec;
      fSecSelRec.SetRawOnly(fRnrCtx->GetSelectBuffer()->RawRecord(0));
      if (gDebug > 1) fSecSelRec.Print();
      return kTRUE;
   } else {
      fSecSelRec.Reset();
      return kFALSE;
   }
}

//______________________________________________________________________________
void TGLViewer::ApplySelection()
{
   // Process result from last selection (in fSelRec) and
   // extract a new current selection from it.
   // Here we only use physical shape.

   fCurrentSelRec = fSelRec;

   TGLPhysicalShape *selPhys = fSelRec.GetPhysShape();
   fSelectedPShapeRef->SetPShape(selPhys);

   // Inform external client selection has been modified.
   SelectionChanged();

   RequestDraw(TGLRnrCtx::kLODHigh);
}

//______________________________________________________________________________
Bool_t TGLViewer::RequestOverlaySelect(Int_t x, Int_t y)
{
   // Post request for secondary selection rendering of selected object
   // around the window point (x,y).

   // Take select lock on viewer immediately - it is released
   // in the other (drawing) thread - see TGLViewer::DoSecondarySelect().

   if ( ! TakeLock(kSelectLock)) {
      return kFALSE;
   }

   if (!gVirtualX->IsCmdThread())
      return Bool_t(gROOT->ProcessLineFast(Form("((TGLViewer *)0x%lx)->DoOverlaySelect(%d, %d)", (ULong_t)this, x, y)));
   else
      return DoOverlaySelect(x, y);
}

//______________________________________________________________________________
Bool_t TGLViewer::DoOverlaySelect(Int_t x, Int_t y)
{
   // Perform GL selection, picking overlay objects only.
   // Return TRUE if the selected overlay-element has changed.

   R__LOCKGUARD2(gROOTMutex);

   if (CurrentLock() != kSelectLock) {
      Error("TGLViewer::DoOverlaySelect", "expected kSelectLock, found %s", LockName(CurrentLock()));
      return kFALSE;
   }

   TGLUtil::PointToViewport(x, y);

   TUnlocker ulck(this);

   MakeCurrent();

   fRnrCtx->BeginSelection(x, y, TGLUtil::GetPickingRadius());
   glRenderMode(GL_SELECT);

   PreRenderOverlaySelection();
   RenderOverlay(TGLOverlayElement::kActive, kTRUE);
   PostRenderOverlaySelection();

   Int_t nHits = glRenderMode(GL_RENDER);
   fRnrCtx->EndSelection(nHits);

   // Process overlay selection.
   TGLOverlayElement * selElm = 0;
   if (nHits > 0)
   {
      Int_t idx = 0;
      while (idx < nHits && FindClosestOverlayRecord(fOvlSelRec, idx))
      {
         TGLOverlayElement* el = fOvlSelRec.GetOvlElement();
         if (el == fCurrentOvlElm)
         {
            if (el->MouseStillInside(fOvlSelRec))
            {
               selElm = el;
               break;
            }
         }
         else if (el->MouseEnter(fOvlSelRec))
         {
            selElm = el;
            break;
         }
         ++idx;
      }
   }
   else
   {
      fOvlSelRec.Reset();
   }

   ReleaseLock(kSelectLock);

   if (fCurrentOvlElm != selElm)
   {
      if (fCurrentOvlElm) fCurrentOvlElm->MouseLeave();
      fCurrentOvlElm = selElm;
      return kTRUE;
   }
   else
   {
      return kFALSE;
   }
}

//______________________________________________________________________________
void TGLFaderHelper::MakeFadeStep()
{
   // Make one fading step and request redraw.

   Float_t fade = fViewer->GetFader();

   if (fade == fFadeTarget) {
      delete this; return;
   }
   if (TMath::Abs(fFadeTarget - fade) < 1e-3) {
      fViewer->SetFader(fFadeTarget);
      fViewer->RequestDraw(TGLRnrCtx::kLODHigh);
      delete this;
      return;
   }

   Float_t dt = fTime/fNSteps;
   Float_t df = (fFadeTarget - fade)/fNSteps;
   fViewer->SetFader(fade + df);
   fViewer->RequestDraw(TGLRnrCtx::kLODHigh);
   fTime -= dt; --fNSteps;
   TTimer::SingleShot(TMath::CeilNint(1000*dt),
                      "TGLFaderHelper", this, "MakeFadeStep()");
}

//______________________________________________________________________________
void TGLViewer::AutoFade(Float_t fade, Float_t time, Int_t steps)
{
   // Animate fading from curernt value to fade over given time (sec)
   // and number of steps.

   TGLFaderHelper* fh = new TGLFaderHelper(this, fade, time, steps);
   fh->MakeFadeStep();
}

//______________________________________________________________________________
void TGLViewer::UseDarkColorSet()
{
   // Use the dark color-set.

   fRnrCtx->ChangeBaseColorSet(&fDarkColorSet);
   RefreshPadEditor(this);
}

//______________________________________________________________________________
void TGLViewer::UseLightColorSet()
{
   // Use the light color-set.

   fRnrCtx->ChangeBaseColorSet(&fLightColorSet);
   RefreshPadEditor(this);
}

//______________________________________________________________________________
void TGLViewer::SwitchColorSet()
{
   // Swtich between dark and light colorsets.

   if (IsUsingDefaultColorSet())
   {
      Info("SwitchColorSet()", "Global color-set is in use, switch not supported.");
      return;
   }

   if (fRnrCtx->GetBaseColorSet() == &fLightColorSet)
      UseDarkColorSet();
   else
      UseLightColorSet();
}

//______________________________________________________________________________
void TGLViewer::UseDefaultColorSet(Bool_t x)
{
   // Set usage of the default color set.

   if (x)
      fRnrCtx->ChangeBaseColorSet(&fgDefaultColorSet);
   else
      fRnrCtx->ChangeBaseColorSet(&fDarkColorSet);
   RefreshPadEditor(this);
}

//______________________________________________________________________________
Bool_t TGLViewer::IsUsingDefaultColorSet() const
{
   // Check if the viewer is using the default color set.
   // If yes, some operations might be disabled.

   return fRnrCtx->GetBaseColorSet() == &fgDefaultColorSet;
}

//______________________________________________________________________________
void TGLViewer::SetClearColor(Color_t col)
{
   // Set background method.
   // Deprecated method - set background color in the color-set.

   fRnrCtx->GetBaseColorSet()->Background().SetColor(col);
}

//______________________________________________________________________________
TGLColorSet& TGLViewer::GetDefaultColorSet()
{
   // Returns reference to the default color-set.
   // Static function.

   return fgDefaultColorSet;
}

//______________________________________________________________________________
void TGLViewer::UseDefaultColorSetForNewViewers(Bool_t x)
{
   // Sets static flag that determines if new viewers should use the
   // default color-set.
   // This is false at startup.

   fgUseDefaultColorSetForNewViewers = x;
}

//______________________________________________________________________________
Bool_t TGLViewer::IsUsingDefaultColorSetForNewViewers()
{
   // Returns the value of the static flag that determines if new
   // viewers should use the default color-set.
   // This is false at startup.

   return fgUseDefaultColorSetForNewViewers;
}

//______________________________________________________________________________
Bool_t TGLViewer::IsColorSetDark() const
{
   // Returns true if curremt color set is dark.

   return fRnrCtx->GetBaseColorSet() == &fDarkColorSet;
}

/**************************************************************************/
// Viewport
/**************************************************************************/

//______________________________________________________________________________
void TGLViewer::SetViewport(Int_t x, Int_t y, Int_t width, Int_t height)
{
   // Set viewer viewport (window area) with bottom/left at (x,y), with
   // dimensions 'width'/'height'

   if (fStereo && ! fStereoQuadBuf) width /= 2;

   // Only process if changed
   if (fViewport.X() == x && fViewport.Y() == y &&
       fViewport.Width() == width && fViewport.Height() == height) {
      return;
   }

   fViewport.Set(x, y, width, height);
   fCurrentCamera->SetViewport(fViewport);

   if (gDebug > 2) {
      Info("TGLViewer::SetViewport", "updated - corner %d,%d dimensions %d,%d", x, y, width, height);
   }
}

void TGLViewer::SetViewport(const TGLRect& vp)
{
   // Set viewr viewport from TGLRect.

   SetViewport(vp.X(), vp.Y(), vp.Width(), vp.Height());
}

/**************************************************************************/
// Camera methods
/**************************************************************************/

//______________________________________________________________________________
TGLCamera& TGLViewer::RefCamera(ECameraType cameraType)
{
   // Return camera reference by type.

   // TODO: Move these into a vector!
   switch(cameraType) {
      case kCameraPerspXOZ:
         return fPerspectiveCameraXOZ;
      case kCameraPerspYOZ:
         return fPerspectiveCameraYOZ;
      case kCameraPerspXOY:
         return fPerspectiveCameraXOY;
      case kCameraOrthoXOY:
         return fOrthoXOYCamera;
      case kCameraOrthoXOZ:
         return fOrthoXOZCamera;
      case kCameraOrthoZOY:
         return fOrthoZOYCamera;
      case kCameraOrthoXnOY:
         return fOrthoXnOYCamera;
      case kCameraOrthoXnOZ:
         return fOrthoXnOZCamera;
      case kCameraOrthoZnOY:
         return fOrthoZnOYCamera;
      default:
         Error("TGLViewer::SetCurrentCamera", "invalid camera type");
         return *fCurrentCamera;
   }
}

//______________________________________________________________________________
void TGLViewer::SetCurrentCamera(ECameraType cameraType)
{
   // Set current active camera - 'cameraType' one of:
   //   kCameraPerspX,    kCameraPerspY,    kCameraPerspZ,
   //   kCameraOrthoXOY,  kCameraOrthoXOZ,  kCameraOrthoZOY,
   //   kCameraOrthoXnOY, kCameraOrthoXnOZ, kCameraOrthoZnOY

   if (IsLocked()) {
      Error("TGLViewer::SetCurrentCamera", "expected kUnlocked, found %s", LockName(CurrentLock()));
      return;
   }

   // TODO: Move these into a vector!
   TGLCamera *prev = fCurrentCamera;
   switch (cameraType)
   {
      case kCameraPerspXOZ: {
         fCurrentCamera = &fPerspectiveCameraXOZ;
         break;
      }
      case kCameraPerspYOZ: {
         fCurrentCamera = &fPerspectiveCameraYOZ;
         break;
      }
      case kCameraPerspXOY: {
         fCurrentCamera = &fPerspectiveCameraXOY;
         break;
      }
      case kCameraOrthoXOY: {
         fCurrentCamera = &fOrthoXOYCamera;
         break;
      }
      case kCameraOrthoXOZ: {
         fCurrentCamera = &fOrthoXOZCamera;
         break;
      }
      case kCameraOrthoZOY: {
         fCurrentCamera = &fOrthoZOYCamera;
         break;
      }
      case kCameraOrthoXnOY: {
         fCurrentCamera = &fOrthoXnOYCamera;
         break;
      }
      case kCameraOrthoXnOZ: {
         fCurrentCamera = &fOrthoXnOZCamera;
         break;
      }
      case kCameraOrthoZnOY: {
         fCurrentCamera = &fOrthoZnOYCamera;
         break;
      }
      default: {
         Error("TGLViewer::SetCurrentCamera", "invalid camera type");
         break;
      }
   }

   if (fCurrentCamera != prev)
   {
      // Ensure any viewport has been propigated to the current camera
      fCurrentCamera->SetViewport(fViewport);
      RefreshPadEditor(this);

      if (fAutoRotator)
      {
         if (fAutoRotator->IsRunning())
         {
            fAutoRotator->Stop();
         }
         else
         {
            if (fAutoRotator->GetCamera() == fCurrentCamera)
            {
               fAutoRotator->Start();
            }
         }
      }

      RequestDraw(TGLRnrCtx::kLODHigh);
   }
}

//______________________________________________________________________________
void TGLViewer::SetOrthoCamera(ECameraType camera,
                               Double_t zoom, Double_t dolly,
                               Double_t center[3],
                               Double_t hRotate, Double_t vRotate)
{
   // Set an orthographic camera to supplied configuration - note this
   // does not need to be the current camera - though you will not see
   // the effect if it is not.
   //
   // 'camera' defines the ortho camera - one of kCameraOrthoXOY / XOZ / ZOY
   // 'left' / 'right' / 'top' / 'bottom' define the WORLD coordinates which
   // corresepond with the left/right/top/bottom positions on the GL viewer viewport
   // E.g. for kCameraOrthoXOY camera left/right are X world coords,
   // top/bottom are Y world coords
   // As this is an orthographic camera the other axis (in eye direction) is
   // no relevant. The near/far clip planes are set automatically based in scene
   // contents

   // TODO: Move these into a vector!
   switch(camera) {
      case kCameraOrthoXOY: {
         fOrthoXOYCamera.Configure(zoom, dolly, center, hRotate, vRotate);
         if (fCurrentCamera == &fOrthoXOYCamera) {
            RequestDraw(TGLRnrCtx::kLODHigh);
         }
         break;
      }
      case kCameraOrthoXOZ: {
         fOrthoXOZCamera.Configure(zoom, dolly, center, hRotate, vRotate);
         if (fCurrentCamera == &fOrthoXOZCamera) {
            RequestDraw(TGLRnrCtx::kLODHigh);
         }
         break;
      }
      case kCameraOrthoZOY: {
         fOrthoZOYCamera.Configure(zoom, dolly, center, hRotate, vRotate);
         if (fCurrentCamera == &fOrthoZOYCamera) {
            RequestDraw(TGLRnrCtx::kLODHigh);
         }
         break;
      }
      default: {
         Error("TGLViewer::SetOrthoCamera", "invalid camera type");
         break;
      }
   }
}

//______________________________________________________________________________
void TGLViewer::SetPerspectiveCamera(ECameraType camera,
                                     Double_t fov, Double_t dolly,
                                     Double_t center[3],
                                     Double_t hRotate, Double_t vRotate)
{
   // Set a perspective camera to supplied configuration - note this
   // does not need to be the current camera - though you will not see
   // the effect if it is not.
   //
   // 'camera' defines the persp camera - one of kCameraPerspXOZ, kCameraPerspYOZ, kCameraPerspXOY
   // 'fov' - field of view (lens angle) in degrees (clamped to 0.1 - 170.0)
   // 'dolly' - distance from 'center'
   // 'center' - world position from which dolly/hRotate/vRotate are measured
   //             camera rotates round this, always facing in (in center of viewport)
   // 'hRotate' - horizontal rotation from initial configuration in degrees
   // 'hRotate' - vertical rotation from initial configuration in degrees

   // TODO: Move these into a vector!
   switch(camera) {
      case kCameraPerspXOZ: {
         fPerspectiveCameraXOZ.Configure(fov, dolly, center, hRotate, vRotate);
         if (fCurrentCamera == &fPerspectiveCameraXOZ) {
            RequestDraw(TGLRnrCtx::kLODHigh);
         }
         break;
      }
      case kCameraPerspYOZ: {
         fPerspectiveCameraYOZ.Configure(fov, dolly, center, hRotate, vRotate);
         if (fCurrentCamera == &fPerspectiveCameraYOZ) {
            RequestDraw(TGLRnrCtx::kLODHigh);
         }
         break;
      }
      case kCameraPerspXOY: {
         fPerspectiveCameraXOY.Configure(fov, dolly, center, hRotate, vRotate);
         if (fCurrentCamera == &fPerspectiveCameraXOY) {
            RequestDraw(TGLRnrCtx::kLODHigh);
         }
         break;
      }
      default: {
         Error("TGLViewer::SetPerspectiveCamera", "invalid camera type");
         break;
      }
   }
}

//______________________________________________________________________________
void TGLViewer::ReinitializeCurrentCamera(const TGLVector3& hAxis, const TGLVector3& vAxis, Bool_t redraw)
{
   // Change base-vectors defining the camera-base transformation of current
   // camera. hAxis and vAxis are the default directions for forward
   // (inverted) and upwards.

   TGLMatrix& cb = fCurrentCamera->RefCamBase();
   cb.Set(cb.GetTranslation(), vAxis, hAxis);
   fCurrentCamera->Setup(fOverallBoundingBox, kTRUE);
   if (redraw)
      RequestDraw();
}

//______________________________________________________________________________
TGLAutoRotator* TGLViewer::GetAutoRotator()
{
   // Get the auto-rotator for this viewer.

   if (fAutoRotator == 0)
      fAutoRotator = new TGLAutoRotator(this);
   return fAutoRotator;
}

//______________________________________________________________________________
void TGLViewer::SetAutoRotator(TGLAutoRotator* ar)
{
   // Set the auto-rotator for this viewer. The old rotator is deleted.

   delete fAutoRotator;
   fAutoRotator = ar;
}

//______________________________________________________________________________
void TGLViewer::SetStereo(Bool_t stereo, Bool_t quad_buf)
{
   // Enable stereo rendering.
   // If quad_buf is true rendering is done into separate left and right GL
   // buffers. This requires hardware support. Otherwise left and right images
   // get rendered into left and right half of the window.
   // Note that mouse highlighting and selection will not work exactly right
   // as image for each eye gets slightly shifted and there are two different
   // directions through the mouse pointer, one for each eye.

   if (stereo != fStereo)
   {
      fStereo = stereo;
      fStereoQuadBuf = quad_buf;
      if (fStereo)
         SetViewport(fViewport.X(), fViewport.Y(),   fViewport.Width(), fViewport.Height());
      else
         SetViewport(fViewport.X(), fViewport.Y(), 2*fViewport.Width(), fViewport.Height());
   }
   RequestDraw(TGLRnrCtx::kLODHigh);
}

/**************************************************************************/
// Guide methods
/**************************************************************************/

//______________________________________________________________________________
void TGLViewer::GetGuideState(Int_t & axesType, Bool_t & axesDepthTest, Bool_t & referenceOn, Double_t referencePos[3]) const
{
   // Fetch the state of guides (axes & reference markers) into arguments

   axesType = fAxesType;
   axesDepthTest = fAxesDepthTest;

   referenceOn = fReferenceOn;
   referencePos[0] = fReferencePos.X();
   referencePos[1] = fReferencePos.Y();
   referencePos[2] = fReferencePos.Z();
}

//______________________________________________________________________________
void TGLViewer::SetGuideState(Int_t axesType, Bool_t axesDepthTest, Bool_t referenceOn, const Double_t referencePos[3])
{
   // Set the state of guides (axes & reference markers) from arguments.

   fAxesType    = axesType;
   fAxesDepthTest = axesDepthTest;
   fReferenceOn = referenceOn;
   if (referencePos)
      fReferencePos.Set(referencePos[0], referencePos[1], referencePos[2]);
   if (fGLDevice != -1)
      gGLManager->MarkForDirectCopy(fGLDevice, kTRUE);
   RequestDraw();
}

//______________________________________________________________________________
void TGLViewer::SetDrawCameraCenter(Bool_t x)
{
   // Draw camera look at and rotation point.

   fDrawCameraCenter = x;
   RequestDraw();
}

// Selected physical
//______________________________________________________________________________
const TGLPhysicalShape * TGLViewer::GetSelected() const
{
   // Return selected physical shape.

   return fSelectedPShapeRef->GetPShape();
}

/**************************************************************************/
/**************************************************************************/

//______________________________________________________________________________
void TGLViewer::MouseOver(TGLPhysicalShape *shape)
{
   // Emit MouseOver signal.

   Emit("MouseOver(TGLPhysicalShape*)", (Long_t)shape);
}

//______________________________________________________________________________
void TGLViewer::MouseOver(TGLPhysicalShape *shape, UInt_t state)
{
   // Emit MouseOver signal.

   Long_t args[2];
   args[0] = (Long_t)shape;
   args[1] = state;
   Emit("MouseOver(TGLPhysicalShape*,UInt_t)", args);
}

//______________________________________________________________________________
void TGLViewer::MouseOver(TObject *obj, UInt_t state)
{
   // Emit MouseOver signal.

   Long_t args[2];
   args[0] = (Long_t)obj;
   args[1] = state;
   Emit("MouseOver(TObject*,UInt_t)", args);
}

//______________________________________________________________________________
void TGLViewer::ReMouseOver(TObject *obj, UInt_t state)
{
   // Emit MouseOver signal.

   Long_t args[2];
   args[0] = (Long_t)obj;
   args[1] = state;
   Emit("ReMouseOver(TObject*,UInt_t)", args);
}


//______________________________________________________________________________
void TGLViewer::UnMouseOver(TObject *obj, UInt_t state)
{
   // Emit UnMouseOver signal.

   Long_t args[2];
   args[0] = (Long_t)obj;
   args[1] = state;
   Emit("UnMouseOver(TObject*,UInt_t)", args);
}

//______________________________________________________________________________
void TGLViewer::Clicked(TObject *obj)
{
   // Emit Clicked signal.

   Emit("Clicked(TObject*)", (Long_t)obj);
}

//______________________________________________________________________________
void TGLViewer::Clicked(TObject *obj, UInt_t button, UInt_t state)
{
   // Emit Clicked signal with button id and modifier state.

   Long_t args[3];
   args[0] = (Long_t)obj;
   args[1] = button;
   args[2] = state;
   Emit("Clicked(TObject*,UInt_t,UInt_t)", args);
}


//______________________________________________________________________________
void TGLViewer::ReClicked(TObject *obj, UInt_t button, UInt_t state)
{
   // Emit ReClicked signal with button id and modifier state.

   Long_t args[3];
   args[0] = (Long_t)obj;
   args[1] = button;
   args[2] = state;
   Emit("ReClicked(TObject*,UInt_t,UInt_t)", args);
}

//______________________________________________________________________________
void TGLViewer::UnClicked(TObject *obj, UInt_t button, UInt_t state)
{
   // Emit UnClicked signal with button id and modifier state.

   Long_t args[3];
   args[0] = (Long_t)obj;
   args[1] = button;
   args[2] = state;
   Emit("UnClicked(TObject*,UInt_t,UInt_t)", args);
}

//______________________________________________________________________________
void TGLViewer::MouseIdle(TGLPhysicalShape *shape, UInt_t posx, UInt_t posy)
{
   // Emit MouseIdle signal.

   Long_t args[3];
   static UInt_t oldx = 0, oldy = 0;

   if (oldx != posx || oldy != posy) {
      args[0] = (Long_t)shape;
      args[1] = posx;
      args[2] = posy;
      Emit("MouseIdle(TGLPhysicalShape*,UInt_t,UInt_t)", args);
      oldx = posx;
      oldy = posy;
   }
}

/**************************************************************************/
/**************************************************************************/
//______________________________________________________________________________
Int_t TGLViewer::DistancetoPrimitive(Int_t /*px*/, Int_t /*py*/)
{
   // Calcaulate and return pixel distance to nearest viewer object from
   // window location px, py
   // This is provided for use when embedding GL viewer into pad

   // Can't track the indvidual objects in rollover. Just set the viewer as the
   // selected object, and return 0 (object identified) so we receive ExecuteEvent calls
   gPad->SetSelected(this);
   return 0;
}

//______________________________________________________________________________
void TGLViewer::ExecuteEvent(Int_t event, Int_t px, Int_t py)
{
   // Process event of type 'event' - one of EEventType types,
   // occuring at window location px, py
   // This is provided for use when embedding GL viewer into pad

   if (fEventHandler)
      return fEventHandler->ExecuteEvent(event, px, py);
}

//______________________________________________________________________________
void TGLViewer::PrintObjects()
{
   // Pass viewer for print capture by TGLOutput.

   TGLOutput::Capture(*this);
}

//______________________________________________________________________________
void TGLViewer::SelectionChanged()
{
   // Update GUI components for embedded viewer selection change.

   if (!fGedEditor)
      return;

   TGLPhysicalShape *selected = const_cast<TGLPhysicalShape*>(GetSelected());

   if (selected) {
      fPShapeWrap->fPShape = selected;
      fGedEditor->SetModel(fPad, fPShapeWrap, kButton1Down);
   } else {
      fPShapeWrap->fPShape = 0;
      fGedEditor->SetModel(fPad, this, kButton1Down);
   }
}

//______________________________________________________________________________
void TGLViewer::OverlayDragFinished()
{
   // An overlay operation can result in change to an object.
   // Refresh geditor.

   if (fGedEditor)
   {
      fGedEditor->SetModel(fPad, fGedEditor->GetModel(), kButton1Down);
   }
}

//______________________________________________________________________________
void TGLViewer::RefreshPadEditor(TObject* obj)
{
   // Update GED editor if it is set.

   if (fGedEditor && (obj == 0 || fGedEditor->GetModel() == obj))
   {
      fGedEditor->SetModel(fPad, fGedEditor->GetModel(), kButton1Down);
   }
}

//______________________________________________________________________________
void TGLViewer::SetEventHandler(TGEventHandler *handler)
{
   // Set the event-handler. The event-handler is owned by the viewer.
   // If GLWidget is set, the handler is propagated to it.
   //
   // If called with handler=0, the current handler will be deleted
   // (also from TGLWidget).

   if (fEventHandler)
      delete fEventHandler;

   fEventHandler = handler;
   if (fGLWidget)
      fGLWidget->SetEventHandler(fEventHandler);
}

//______________________________________________________________________________
void  TGLViewer::RemoveOverlayElement(TGLOverlayElement* el)
{
   // Remove overlay element.

   if (el == fCurrentOvlElm)
   {
      fCurrentOvlElm = 0;
   }
   TGLViewerBase::RemoveOverlayElement(el);
}

//______________________________________________________________________________
void TGLViewer::ClearCurrentOvlElm()
{
   // Reset current overlay-element to zero, eventually notifying the
   // old one that the mouse has left.
   // Usually called when mouse leaves the window.

   if (fCurrentOvlElm)
   {
      fCurrentOvlElm->MouseLeave();
      fCurrentOvlElm = 0;
      RequestDraw();
   }
}