TGLScaleManip.cxx

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// @(#)root/gl:$Id$
// Author:  Richard Maunder  16/09/2005

/*************************************************************************
 * Copyright (C) 1995-2005, 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 "TGLScaleManip.h"
#include "TGLPhysicalShape.h"
#include "TGLCamera.h"
#include "TGLIncludes.h"

/** \class TGLScaleManip
\ingroup opengl
Scale manipulator - attaches to physical shape and draws local axes
widgets with box heads. User can mouse over (turns yellow) and L
click/drag to scale along this axis.
*/

ClassImp(TGLScaleManip);

////////////////////////////////////////////////////////////////////////////////
/// Construct scale manipulator not bound to any physical shape.

TGLScaleManip::TGLScaleManip()
{
}

////////////////////////////////////////////////////////////////////////////////
/// Construct scale manipulator bound to TGLPhysicalShape 'shape'.

TGLScaleManip::TGLScaleManip(TGLPhysicalShape * shape) :
   TGLManip(shape)
{
}

////////////////////////////////////////////////////////////////////////////////
/// Destroy the scale manipulator

TGLScaleManip::~TGLScaleManip()
{
}

////////////////////////////////////////////////////////////////////////////////
/// Draw scale manipulator - tubes with box heads, in local axes of
/// attached shape, in red(X), green(Y) and blue(Z), with white center sphere.
/// If selected widget (mouse over) this is drawn in active colour (yellow).

void TGLScaleManip::Draw(const TGLCamera & camera) const
{
   if (!fShape) {
      return;
   }

   // Get draw scales
   const TGLBoundingBox & box = fShape->BoundingBox();
   Double_t baseScale;
   TGLVector3 axisScale[3];
   CalcDrawScale(box, camera, baseScale, axisScale);

   // Get permitted manipulations on shape
   TGLPhysicalShape::EManip manip = fShape->GetManip();

   glEnable(GL_BLEND);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
   glDisable(GL_CULL_FACE);

   // Draw three axis widgets out of bounding box where permitted
   // Not drawing will prevent interaction
   // GL name loading for hit testing - 0 reserved for no selection
   if (manip & TGLPhysicalShape::kScaleX) {
      glPushName(1);
      TGLUtil::DrawLine(box.Center(), axisScale[0], TGLUtil::kLineHeadBox,
                        baseScale, ColorFor(1));
      glPopName();
   } else {
      TGLUtil::DrawLine(box.Center(), axisScale[0], TGLUtil::kLineHeadBox,
                        baseScale, TGLUtil::fgGrey);
   }
   if (manip & TGLPhysicalShape::kScaleY) {
      glPushName(2);
      TGLUtil::DrawLine(box.Center(), axisScale[1], TGLUtil::kLineHeadBox,
                        baseScale, ColorFor(2));
      glPopName();
   } else {
      TGLUtil::DrawLine(box.Center(), axisScale[1], TGLUtil::kLineHeadBox,
                        baseScale, TGLUtil::fgGrey);
   }
   if (manip & TGLPhysicalShape::kScaleZ) {
      glPushName(3);
      TGLUtil::DrawLine(box.Center(), axisScale[2], TGLUtil::kLineHeadBox,
                        baseScale, ColorFor(3));
      glPopName();
   } else {
      TGLUtil::DrawLine(box.Center(), axisScale[2], TGLUtil::kLineHeadBox,
                        baseScale, TGLUtil::fgGrey);
   }
   // Draw white center sphere
   TGLUtil::DrawSphere(box.Center(), baseScale/2.0, TGLUtil::fgWhite);

   glEnable(GL_CULL_FACE);
   glDisable(GL_BLEND);
}

////////////////////////////////////////////////////////////////////////////////
/// Handle mouse button event over manipulator - returns kTRUE if
/// redraw required kFALSE otherwise.

Bool_t TGLScaleManip::HandleButton(const Event_t   & event,
                                   const TGLCamera & camera)
{
   if (event.fType == kButtonPress && fSelectedWidget != 0) {
      fStartScale = fShape->GetScale();
   }

   return TGLManip::HandleButton(event, camera);
}

////////////////////////////////////////////////////////////////////////////////
/// Handle mouse motion over manipulator - if active (selected
/// widget) scale physical along selected widget (axis) of the
/// manipulator, so it tracks mouse action. Returns kTRUE if redraw
/// required kFALSE otherwise.

Bool_t TGLScaleManip::HandleMotion(const Event_t & event,
                                   const TGLCamera & camera)
{
   if (fActive) {
      // Find mouse delta projected into world at attached object center
      TGLVector3 shift = camera.ViewportDeltaToWorld(fShape->BoundingBox().Center(),
                                                     event.fX - fFirstMouse.GetX(),
                                                     -event.fY + fFirstMouse.GetY()); // Y inverted

      UInt_t axisIndex = fSelectedWidget - 1; // Ugg sort out axis / widget id mapping
      TGLVector3 widgetAxis = fShape->BoundingBox().Axis(axisIndex, kTRUE);

      // Scale by projected screen factor
      TGLVector3 screenScale = camera.ViewportDeltaToWorld(fShape->BoundingBox().Center(), 500, 500);
      Double_t factor = -5.0*Dot(shift, widgetAxis) / screenScale.Mag();

      TGLVector3 newScale = fStartScale;
      newScale[axisIndex] += factor;
      LimitScale(newScale[axisIndex]);
      fShape->Scale(newScale);

      fLastMouse.SetX(event.fX);
      fLastMouse.SetY(event.fY);

      return kTRUE;
   }
   return kFALSE;
}

////////////////////////////////////////////////////////////////////////////////
/// Clamp scale to sizable values: 1000 - 1/1000
/// Guards against div by zero problems.

void TGLScaleManip::LimitScale(Double_t & factor) const
{
   if (factor < 1e-4) {
      factor = 1e-4;
   }
   if (factor > 1e+4) {
      factor = 1e+4;
   }
}