TGLLogicalShape.cxx

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

#include "TGLLogicalShape.h"
#include "TGLPhysicalShape.h"
#include "TGLRnrCtx.h"
#include "TGLScene.h"
#include "TGLCamera.h"
#include "TGLSelectRecord.h"
#include "TGLContext.h"
#include "TGLIncludes.h"

#include "TBuffer3D.h"
#include "TClass.h"
#include "TContextMenu.h"
#include "TEnv.h"


/** \class TGLLogicalShape
\ingroup opengl
Abstract logical shape - a GL 'drawable' - base for all shapes -
faceset sphere etc. Logical shapes are a unique piece of geometry,
described in it's local frame - e.g if we have three spheres in :

  - Sphere A - Radius r1, center v1
  - Sphere B - Radius r2, center v2
  - Sphere C - Radius r1, center v3

Spheres A and C can share a common logical sphere of radius r1 - and
place them with two physicals with translations of v1 & v2.  Sphere B
requires a different logical (radius r2), placed with physical with
translation v2.

Physical shapes know about and can share logicals. Logicals do not
about (aside from reference counting) physicals or share them.

This sharing of logical shapes greatly reduces memory consumption and
scene (re)build times in typical detector geometries which have many
repeated objects placements.

TGLLogicalShapes have reference counting, performed by the client
physical shapes which are using it.

Display list information is also stored here, possibly per LOD
level. Most classes do not support LOD (only sphere and tube) and
therefore reasonable defaults are encoded in the following virtual
functions:
~~~ {.cpp}
 * ELODAxes SupportedLODAxes()  { return kLODAxesNone; }
 * Int_t    DLCacheSize()       { return 1; }
 * UInt_t   DLOffset(lod);      // Transform lod into DL offset.
 * Short_t  QuantizeShapeLOD(); // Quantize lod.
~~~
Classes that have per-LOD display-lists than override these functions.
'UShort_t fDLValid' is used as a bit-field determining validity of
each quantized LOD-level; hopefully one will not have more than 16
LOD levels per class.
See also: TGLPhysicalShape::CalculateShapeLOD() where LOD is calculated.

See base/src/TVirtualViewer3D for description of common external 3D
viewer architecture and how external viewer clients use it.
*/

ClassImp(TGLLogicalShape);

Bool_t TGLLogicalShape::fgIgnoreSizeForCameraInterest = kFALSE;

Bool_t TGLLogicalShape::fgUseDLs            = kTRUE;
Bool_t TGLLogicalShape::fgUseDLsForVertArrs = kTRUE;

////////////////////////////////////////////////////////////////////////////////
/// Constructor.

TGLLogicalShape::TGLLogicalShape() :
   fRef           (0),
   fFirstPhysical (0),
   fExternalObj   (0),
   fScene         (0),
   fDLBase        (0),
   fDLSize        (1),
   fDLValid       (0),
   fDLCache       (kTRUE),
   fRefStrong     (kFALSE),
   fOwnExtObj     (kFALSE)
{
}

////////////////////////////////////////////////////////////////////////////////
/// Constructor with external object.

TGLLogicalShape::TGLLogicalShape(TObject* obj) :
   fRef           (0),
   fFirstPhysical (0),
   fExternalObj   (obj),
   fScene         (0),
   fDLBase        (0),
   fDLSize        (1),
   fDLValid       (0),
   fDLCache       (kTRUE),
   fRefStrong     (kFALSE),
   fOwnExtObj     (kFALSE)
{
}

////////////////////////////////////////////////////////////////////////////////
/// Constructor from TBuffer3D.

TGLLogicalShape::TGLLogicalShape(const TBuffer3D & buffer) :
   fRef           (0),
   fFirstPhysical (0),
   fExternalObj   (buffer.fID),
   fScene         (0),
   fDLBase        (0),
   fDLSize        (1),
   fDLValid       (0),
   fDLCache       (kTRUE),
   fRefStrong     (kFALSE),
   fOwnExtObj     (kFALSE)
{
   // Use the bounding box in buffer if valid
   if (buffer.SectionsValid(TBuffer3D::kBoundingBox)) {
      fBoundingBox.Set(buffer.fBBVertex);
   } else if (buffer.SectionsValid(TBuffer3D::kRaw)) {
   // otherwise use the raw points to generate one
      fBoundingBox.SetAligned(buffer.NbPnts(), buffer.fPnts);
   }

   // If the logical is created without an external object reference,
   // we create a generic  here and delete it during the destruction.
   if (fExternalObj == 0)
   {
      fExternalObj = new TNamed("Generic object", "Internal object created for bookkeeping.");
      fOwnExtObj = kTRUE;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Destroy logical shape.

TGLLogicalShape::~TGLLogicalShape()
{
   // Physicals should have been cleared elsewhere as they are managed
   // by the scene. But this could change.
   if (fRef > 0) {
      Warning("TGLLogicalShape::~TGLLogicalShape", "some physicals still lurking around.");
      DestroyPhysicals();
   }
   DLCachePurge();
   if (fOwnExtObj)
   {
      delete fExternalObj;
   }
}


/**************************************************************************/
// Physical shape ref-counting, replica management
/**************************************************************************/

////////////////////////////////////////////////////////////////////////////////
/// Add reference to given physical shape.

void TGLLogicalShape::AddRef(TGLPhysicalShape* phys) const
{
   phys->fNextPhysical = fFirstPhysical;
   fFirstPhysical = phys;
   ++fRef;
}

////////////////////////////////////////////////////////////////////////////////
/// Remove reference to given physical shape, potentially deleting
/// *this* object when hitting zero ref-count (if fRefStrong is
/// true).

void TGLLogicalShape::SubRef(TGLPhysicalShape* phys) const
{
   assert(phys != 0);

   Bool_t found = kFALSE;
   if (fFirstPhysical == phys) {
      fFirstPhysical = phys->fNextPhysical;
      found = kTRUE;
   } else {
      TGLPhysicalShape *shp1 = fFirstPhysical, *shp2;
      while ((shp2 = shp1->fNextPhysical) != 0) {
         if (shp2 == phys) {
            shp1->fNextPhysical = shp2->fNextPhysical;
            found = kTRUE;
            break;
         }
         shp1 = shp2;
      }
   }
   if (found == kFALSE) {
      Error("TGLLogicalShape::SubRef", "Attempt to un-ref an unregistered physical.");
      return;
   }

   if (--fRef == 0 && fRefStrong)
      delete this;
}

////////////////////////////////////////////////////////////////////////////////
/// Destroy all physicals attached to this logical.

void TGLLogicalShape::DestroyPhysicals()
{
   TGLPhysicalShape *curr = fFirstPhysical, *next;
   while (curr)
   {
      next = curr->fNextPhysical;
      curr->fLogicalShape = 0;
      --fRef;
      delete curr;
      curr = next;
   }
   assert (fRef == 0);
   fFirstPhysical = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Unreferenced first physical in the list, returning its id and
/// making it fit for destruction somewhere else.
/// Returns 0 if there are no replicas attached.

UInt_t TGLLogicalShape::UnrefFirstPhysical()
{
   if (fFirstPhysical == 0) return 0;

   TGLPhysicalShape *phys = fFirstPhysical;
   UInt_t            phid = phys->ID();
   fFirstPhysical = phys->fNextPhysical;
   phys->fLogicalShape = 0;
   --fRef;
   return phid;
}


/**************************************************************************/
// Bounding-boxes
/**************************************************************************/

////////////////////////////////////////////////////////////////////////////////
/// Update bounding-boxed of all dependent physicals.

void TGLLogicalShape::UpdateBoundingBoxesOfPhysicals()
{
   TGLPhysicalShape* pshp = fFirstPhysical;
   while (pshp)
   {
      pshp->UpdateBoundingBox();
      pshp = pshp->fNextPhysical;
   }
}


/**************************************************************************/
// Display-list cache
/**************************************************************************/

////////////////////////////////////////////////////////////////////////////////
/// Modify capture of draws into display list cache kTRUE - capture,
/// kFALSE direct draw. Return kTRUE is state changed, kFALSE if not.

Bool_t TGLLogicalShape::SetDLCache(Bool_t cache)
{
   if (cache == fDLCache)
      return kFALSE;

   if (fDLCache)
      DLCachePurge();
   fDLCache = cache;
   return kTRUE;
}

////////////////////////////////////////////////////////////////////////////////
/// Returns kTRUE if draws should be display list cached
/// kFALSE otherwise.
///
/// Here we check that:
/// a) fScene is set (Scene manages link to GL-context);
/// b) secondary selection is not in progress as different
///    render-path is usually taken in this case.
///
/// Otherwise we return internal bool.
///
/// Override this in sub-class if different behaviour is required.

Bool_t TGLLogicalShape::ShouldDLCache(const TGLRnrCtx& rnrCtx) const
{
   if (!fDLCache || !fScene ||
       (rnrCtx.SecSelection() && SupportsSecondarySelect()))
   {
      return kFALSE;
   }
   return kTRUE;
}

////////////////////////////////////////////////////////////////////////////////
/// Clear all entries for all LODs for this drawable from the
/// display list cache but keeping the reserved ids from GL context.

void TGLLogicalShape::DLCacheClear()
{
   fDLValid = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Drop all entries for all LODs for this drawable from the display
/// list cache, WITHOUT returning the reserved ids to GL context.
///
/// This is called by scene if it realized that the GL context was
/// destroyed.

void TGLLogicalShape::DLCacheDrop()
{
   fDLBase  = 0;
   fDLValid = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Purge all entries for all LODs for this drawable from the
/// display list cache, returning the reserved ids to GL context.
///
/// If you override this function:
/// 1. call the base-class version from it;
/// 2. call it from the destructor of the derived class!

void TGLLogicalShape::DLCachePurge()
{
   if (fDLBase != 0)
   {
      PurgeDLRange(fDLBase, fDLSize);
      fDLBase  = 0;
      fDLValid = 0;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Purge given display-list range.
/// Utility function.

void TGLLogicalShape::PurgeDLRange(UInt_t base, Int_t size) const
{
   if (fScene)
   {
      fScene->GetGLCtxIdentity()->RegisterDLNameRangeToWipe(base, size);
   }
   else
   {
      Warning("TGLLogicalShape::PurgeDLRange", "Scene unknown, attempting direct deletion.");
      glDeleteLists(base, size);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Logical shapes usually support only discreet LOD values,
/// especially in view of display-list caching.
/// This function should be overriden to perform the desired quantization.
/// See TGLSphere.

Short_t TGLLogicalShape::QuantizeShapeLOD(Short_t shapeLOD,
                                          Short_t /*combiLOD*/) const
{
   return shapeLOD;
}

////////////////////////////////////////////////////////////////////////////////
/// Draw the GL drawable, using draw flags. If DL caching is enabled
/// (see SetDLCache) then attempt to draw from the cache, if not found
/// attempt to capture the draw - done by DirectDraw() - into a new cache entry.
/// If not cached just call DirectDraw() for normal non DL cached drawing.

void TGLLogicalShape::Draw(TGLRnrCtx& rnrCtx) const
{
   // Debug tracing
   if (gDebug > 4) {
      Info("TGLLogicalShape::Draw", "this %ld (class %s) LOD %d", (Long_t)this, IsA()->GetName(), rnrCtx.ShapeLOD());
   }

entry_point:
   // If shape is not cached, or a capture to cache is already in
   // progress perform a direct draw DL can be nested, but not created
   // in nested fashion. As we only build DL on draw demands have to
   // protected against this here.
   // MT: I can't see how this could happen right now ... with
   // rendering from a flat drawable-list.

   if (!fgUseDLs || !ShouldDLCache(rnrCtx) || rnrCtx.IsDLCaptureOpen())
   {
      DirectDraw(rnrCtx);
      return;
   }

   if (fDLBase == 0)
   {
      fDLBase = glGenLists(fDLSize);
      if (fDLBase == 0)
      {
         Warning("TGLLogicalShape::Draw", "display-list registration failed.");
         fDLCache = kFALSE;
         goto entry_point;
      }
   }

   Short_t lod = rnrCtx.ShapeLOD();
   UInt_t  off = DLOffset(lod);
   if ((1<<off) & fDLValid)
   {
      glCallList(fDLBase + off);
   }
   else
   {
      rnrCtx.OpenDLCapture();
      glNewList(fDLBase + off, GL_COMPILE_AND_EXECUTE);
      DirectDraw(rnrCtx);
      glEndList();
      rnrCtx.CloseDLCapture();
      fDLValid |= (1<<off);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Draw the logical shape in highlight mode.
/// If lvl argument is less than 0 (-1 by default), the index into color-set
/// is taken from the physical shape itself.

void TGLLogicalShape::DrawHighlight(TGLRnrCtx& rnrCtx, const TGLPhysicalShape* pshp, Int_t lvl) const
{
   if (lvl < 0) lvl = pshp->GetSelected();

   glColor4ubv(rnrCtx.ColorSet().Selection(lvl).CArr());
   TGLUtil::LockColor();
   Draw(rnrCtx);
   TGLUtil::UnlockColor();
}

////////////////////////////////////////////////////////////////////////////////
/// Virtual method called-back after a secondary selection hit
/// is recorded (see TGLViewer::HandleButton(), Ctrl-Button1).
/// The ptr argument holds the GL pick-record of the closest hit.
///
/// This base-class implementation simply prints out the result.

void TGLLogicalShape::ProcessSelection(TGLRnrCtx& /*rnrCtx*/, TGLSelectRecord& rec)
{
   printf("TGLLogicalShape::ProcessSelection %d names on the stack (z1=%g, z2=%g).\n",
          rec.GetN(), rec.GetMinZ(), rec.GetMaxZ());
   printf("  Names: ");
   for (Int_t j=0; j<rec.GetN(); ++j) printf ("%u ", rec.GetItem(j));
   printf("\n");
}

////////////////////////////////////////////////////////////////////////////////
/// Invoke popup menu or our bound external TObject (if any), using passed
/// 'menu' object, at location 'x' 'y'

void TGLLogicalShape::InvokeContextMenu(TContextMenu& menu, UInt_t x, UInt_t y) const
{
   if (fExternalObj) {
      menu.Popup(x, y, fExternalObj);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Return true if size of this shape should be ignored when determining if
/// the object should be drawn. In this base-class we simply return state of
/// static flag fgIgnoreSizeForCameraInterest.
///
/// Several sub-classes override this virtual function.

Bool_t TGLLogicalShape::IgnoreSizeForOfInterest() const
{
   return fgIgnoreSizeForCameraInterest;
}

////////////////////////////////////////////////////////////////////////////////
/// Get state of static fgIgnoreSizeForCameraInterest flag.
/// When this is true all objects, also very small, will be drawn by GL.

Bool_t TGLLogicalShape::GetIgnoreSizeForCameraInterest()
{
   return fgIgnoreSizeForCameraInterest;
}

////////////////////////////////////////////////////////////////////////////////
/// Set state of static fgIgnoreSizeForCameraInterest flag.

void TGLLogicalShape::SetIgnoreSizeForCameraInterest(Bool_t isfci)
{
   fgIgnoreSizeForCameraInterest = isfci;
}

////////////////////////////////////////////////////////////////////////////////
// Load GL shape settings from ROOT's TEnv into static data members.

void TGLLogicalShape::SetEnvDefaults()
{
   fgUseDLs            = gEnv->GetValue("OpenGL.UseDisplayLists", 1);
   fgUseDLsForVertArrs = gEnv->GetValue("OpenGL.UseDisplayListsForVertexArrays", 1);

   if (!fgUseDLs || !fgUseDLsForVertArrs)
   {
      printf("TGLLogicalShape::SetEnvDefaults() fgUseDLs=%d, fgUseDLsForVertArrs=%d\n",
             fgUseDLs, fgUseDLsForVertArrs);
   }
}