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Reference Guide
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TBuffer3D Class Reference

Generic 3D primitive description class.

See TBuffer3DTypes for producer classes.

Filling TBuffer3D and Adding to Viewer

The viewers behind the TVirtualViewer3D interface differ greatly in their capabilities e.g.

To cope with these situations the object buffer is filled out in negotiation with the viewer. TBuffer3D classes are conceptually divided into enumerated sections Core, BoundingBox, Raw etc (see TBuffer3D.h for more details).


The SectionsValid() / SetSectionsValid / ClearSectionsValid() methods of TBuffer3D are used to test/set/clear these section valid flags.

The sections found in TBuffer3D (Core/BoundingBox/Raw Sizes/Raw) are sufficient to describe any tessellated shape in a generic fashion. An additional ShapeSpecific section in derived shape specific classes allows a more abstract shape description ("a sphere of inner radius x, outer radius y"). This enables a viewer which knows how to draw (tessellate) the shape itself to do so, which can bring considerable performance and quality benefits, while providing a generic fallback suitable for all viewers.

The rules for client negotiation with the viewer are:

If the viewer requires more sections to be completed (Raw/RawSizes) AddObject() will return flags indicating which ones, otherwise it returns kNone. You must fill the buffer and mark these sections valid, and pass the buffer again. A typical code snippet would be:

TBuffer3DSphere sphereBuffer;
// Fill out kCore...
// Fill out kBoundingBox...
// Fill out kShapeSpecific for TBuffer3DSphere
// Try first add to viewer
Int_t reqSections = viewer->AddObject(buffer);
if (reqSections != TBuffer3D::kNone) {
if (reqSections & TBuffer3D::kRawSizes) {
// Fill out kRawSizes...
if (reqSections & TBuffer3D::kRaw) {
// Fill out kRaw...
// Add second time to viewer - ignore return cannot do more

ShapeSpecific: If the viewer can directly display the buffer without filling of the kRaw/kRawSizes section it will not need to request client side tessellation.

Currently we provide the following various shape specific classes, which the OpenGL viewer can take advantage of (see TBuffer3D.h and TBuffer3DTypes.h)

OpenGL only supports solid spheres at present - cut/hollow ones will be requested tessellated.

Anyone is free to add new TBuffer3D classes, but it should be clear that the viewers require updating to be able to take advantage of them. The number of native shapes in OpenGL will be expanded over time.

BoundingBox: You are not obliged to complete this, as any viewer requiring one internally (OpenGL) will build one for you if you do not provide. However to do this the viewer will force you to provide the raw tessellation, and the resulting box will be axis aligned with the overall scene, which is non-ideal for rotated shapes.

As we need to support orientated (rotated) bounding boxes, TBuffer3D requires the 6 vertices of the box. We also provide a convenience function, SetAABoundingBox(), for simpler case of setting an axis aligned bounding box.

Master/Local Reference Frames

The Core section of TBuffer3D contains two members relating to reference frames: fLocalFrame & fLocalMaster. fLocalFrame indicates if any positions in the buffer (bounding box and tessellation vertexes) are in local or master (world frame). fLocalMaster is a standard 4x4 translation matrix (OpenGL column major ordering) for placing the object into the 3D master frame.

If fLocalFrame is kFALSE, fLocalMaster should contain an identity matrix. This is set by default, and can be reset using SetLocalMasterIdentity() function.

Logical & Physical Objects. There are two cases of object addition:

The second case is very typical in geometry packages, GEANT4, where we have very large number repeated placements of relatively few logical (unique) shapes. Some viewers (OpenGL only at present) are able to take advantage of this by identifying unique logical shapes from the fID logical ID member of TBuffer3D. If repeated addition of the same fID is found, the shape is cached already - and the costly tessellation does not need to be sent again. The viewer can also perform internal GL specific caching with considerable performance gains in these cases.

For this to work correctly the logical object in must be described in TBuffer3D in the local reference frame, complete with the local/master translation. The viewer indicates this through the interface method


If this returns kTRUE you can make repeated calls to AddObject(), with TBuffer3D containing the same fID, and different fLocalMaster placements.

For viewers supporting logical/physical objects, the TBuffer3D content refers to the properties of logical object, with the fLocalMaster transform and the fColor and fTransparency attributes, which can be varied for each physical object.

As a minimum requirement all clients must be capable of filling the raw tessellation of the object buffer, in the master reference frame. Conversely viewers must always be capable of displaying the object described by this buffer.

Scene Rebuilds

It should be understood that AddObject is not an explicit command to the viewer

In all these cases AddObject() returns kNone, as it does for successful addition, simply indicating it does not require you to provide further information about this object. You should not try to make any assumptions about what the viewer did with it.

This enables the viewer to be connected to a client which sends potentially millions of objects, and only accept those that are of interest at a certain time, caching the relatively small number of CPU/memory costly logical shapes, and retaining/discarding the physical placements as required. The viewer may decide to force the client to rebuild (republish) the scene (via a TPad repaint at present), and thus collect these objects if the internal viewer state changes. It does this presently by forcing a repaint on the attached TPad object - hence the reason for putting all publishing to the viewer in the attached pad objects Paint() method. We will likely remove this requirement in the future, indicating the rebuild request via a normal ROOT signal, which the client can detect.

Physical IDs

TVirtualViewer3D provides for two methods of object addition:virtual Int_t AddObject(const TBuffer3D & buffer, Bool_t * addChildren = 0)

virtual Int_t AddObject(UInt_t physicalID, const TBuffer3D & buffer, Bool_t * addChildren = 0)

If you use the first (simple) case a viewer using logical/physical pairs SetSectionsValid(TBuffer3D::kBoundingBox); will generate IDs for each physical object internally. In the second you can specify a unique identifier from the client, which allows the viewer to be more efficient. It can now cache both logical and physical objects, and only discard physical objects no longer of interest as part of scene rebuilds.

Child Objects

In many geometries there is a rigid containment hierarchy, and so if the viewer is not interested in a certain object due to limits/size then it will also not be interest in any of the contained branch of descendents. Both AddObject() methods have an addChildren parameter. The viewer will complete this (if passed) indicating if children (contained within the one just sent) are worth adding.

Recycling TBuffer3D

Once add AddObject() has been called, the contents are copied to the viewer internally. You are free to destroy this object, or recycle it for the next object if suitable.

Definition at line 17 of file TBuffer3D.h.

Public Types

enum  EBoolOpCode { kCSUnion, kCSIntersection, kCSDifference, kCSNoOp }
enum  ESection {
  kNone = BIT(0), kCore = BIT(1), kBoundingBox = BIT(2), kShapeSpecific = BIT(3),
  kRawSizes = BIT(4), kRaw = BIT(5), kAll = kCore|kBoundingBox|kShapeSpecific|kRawSizes|kRaw
- Public Types inherited from TObject
enum  {
  kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kInconsistent = 0x08000000,
  kBitMask = 0x00ffffff
enum  { kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) }
enum  EDeprecatedStatusBits { kObjInCanvas = BIT(3) }
enum  EStatusBits {
  kCanDelete = BIT(0), kMustCleanup = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5),
  kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13)

Public Member Functions

 TBuffer3D (Int_t type, UInt_t reqPnts=0, UInt_t reqPntsCapacity=0, UInt_t reqSegs=0, UInt_t reqSegsCapacity=0, UInt_t reqPols=0, UInt_t reqPolsCapacity=0)
 Destructor. More...
virtual ~TBuffer3D ()
 Destructor. More...
void ClearSectionsValid ()
 Clear any sections marked valid. More...
UInt_t GetSections (UInt_t mask) const
UInt_t NbPnts () const
UInt_t NbPols () const
UInt_t NbSegs () const
Bool_t SectionsValid (UInt_t mask) const
void SetAABoundingBox (const Double_t origin[3], const Double_t halfLengths[3])
 Set fBBVertex in kBoundingBox section to a axis aligned (local) BB using supplied origin and box half lengths. More...
void SetLocalMasterIdentity ()
 Set kRaw tessellation section of buffer with supplied sizes. More...
Bool_t SetRawSizes (UInt_t reqPnts, UInt_t reqPntsCapacity, UInt_t reqSegs, UInt_t reqSegsCapacity, UInt_t reqPols, UInt_t reqPolsCapacity)
 Set kRaw tessellation section of buffer with supplied sizes. More...
void SetSectionsValid (UInt_t mask)
Int_t Type () const
- Public Member Functions inherited from TObject
 TObject ()
 TObject constructor. More...
 TObject (const TObject &object)
 TObject copy ctor. More...
virtual ~TObject ()
 TObject destructor. More...
void AbstractMethod (const char *method) const
 Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...
virtual void AppendPad (Option_t *option="")
 Append graphics object to current pad. More...
virtual void Browse (TBrowser *b)
 Browse object. May be overridden for another default action. More...
ULong_t CheckedHash ()
 Checked and record whether for this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object. More...
virtual const char * ClassName () const
 Returns name of class to which the object belongs. More...
virtual void Clear (Option_t *="")
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility. More...
virtual Int_t Compare (const TObject *obj) const
 Compare abstract method. More...
virtual void Copy (TObject &object) const
 Copy this to obj. More...
virtual void Delete (Option_t *option="")
 Delete this object. More...
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Computes distance from point (px,py) to the object. More...
virtual void Draw (Option_t *option="")
 Default Draw method for all objects. More...
virtual void DrawClass () const
 Draw class inheritance tree of the class to which this object belongs. More...
virtual TObjectDrawClone (Option_t *option="") const
 Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad). More...
virtual void Dump () const
 Dump contents of object on stdout. More...
virtual void Error (const char *method, const char *msgfmt,...) const
 Issue error message. More...
virtual void Execute (const char *method, const char *params, Int_t *error=0)
 Execute method on this object with the given parameter string, e.g. More...
virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
 Execute method on this object with parameters stored in the TObjArray. More...
virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
 Execute action corresponding to an event at (px,py). More...
virtual void Fatal (const char *method, const char *msgfmt,...) const
 Issue fatal error message. More...
virtual TObjectFindObject (const char *name) const
 Must be redefined in derived classes. More...
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes. More...
virtual Option_tGetDrawOption () const
 Get option used by the graphics system to draw this object. More...
virtual const char * GetIconName () const
 Returns mime type name of object. More...
virtual const char * GetName () const
 Returns name of object. More...
virtual char * GetObjectInfo (Int_t px, Int_t py) const
 Returns string containing info about the object at position (px,py). More...
virtual Option_tGetOption () const
virtual const char * GetTitle () const
 Returns title of object. More...
virtual UInt_t GetUniqueID () const
 Return the unique object id. More...
virtual Bool_t HandleTimer (TTimer *timer)
 Execute action in response of a timer timing out. More...
virtual ULong_t Hash () const
 Return hash value for this object. More...
Bool_t HasInconsistentHash () const
 Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e. More...
virtual void Info (const char *method, const char *msgfmt,...) const
 Issue info message. More...
virtual Bool_t InheritsFrom (const char *classname) const
 Returns kTRUE if object inherits from class "classname". More...
virtual Bool_t InheritsFrom (const TClass *cl) const
 Returns kTRUE if object inherits from TClass cl. More...
virtual void Inspect () const
 Dump contents of this object in a graphics canvas. More...
void InvertBit (UInt_t f)
virtual Bool_t IsEqual (const TObject *obj) const
 Default equal comparison (objects are equal if they have the same address in memory). More...
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...
R__ALWAYS_INLINE Bool_t IsOnHeap () const
virtual Bool_t IsSortable () const
R__ALWAYS_INLINE Bool_t IsZombie () const
virtual void ls (Option_t *option="") const
 The ls function lists the contents of a class on stdout. More...
void MayNotUse (const char *method) const
 Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More...
virtual Bool_t Notify ()
 This method must be overridden to handle object notification. More...
void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
 Use this method to declare a method obsolete. More...
void operator delete (void *ptr)
 Operator delete. More...
void operator delete[] (void *ptr)
 Operator delete []. More...
voidoperator new (size_t sz)
voidoperator new (size_t sz, void *vp)
voidoperator new[] (size_t sz)
voidoperator new[] (size_t sz, void *vp)
TObjectoperator= (const TObject &rhs)
 TObject assignment operator. More...
virtual void Paint (Option_t *option="")
 This method must be overridden if a class wants to paint itself. More...
virtual void Pop ()
 Pop on object drawn in a pad to the top of the display list. More...
virtual void Print (Option_t *option="") const
 This method must be overridden when a class wants to print itself. More...
virtual Int_t Read (const char *name)
 Read contents of object with specified name from the current directory. More...
virtual void RecursiveRemove (TObject *obj)
 Recursively remove this object from a list. More...
void ResetBit (UInt_t f)
virtual void SaveAs (const char *filename="", Option_t *option="") const
 Save this object in the file specified by filename. More...
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save a primitive as a C++ statement(s) on output stream "out". More...
void SetBit (UInt_t f, Bool_t set)
 Set or unset the user status bits as specified in f. More...
void SetBit (UInt_t f)
virtual void SetDrawOption (Option_t *option="")
 Set drawing option for object. More...
virtual void SetUniqueID (UInt_t uid)
 Set the unique object id. More...
virtual void SysError (const char *method, const char *msgfmt,...) const
 Issue system error message. More...
R__ALWAYS_INLINE Bool_t TestBit (UInt_t f) const
Int_t TestBits (UInt_t f) const
virtual void UseCurrentStyle ()
 Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More...
virtual void Warning (const char *method, const char *msgfmt,...) const
 Issue warning message. More...
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
 Write this object to the current directory. More...
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write this object to the current directory. More...

Static Public Member Functions

static UInt_t DecCSLevel ()
 Decrement CS level. More...
static UInt_t GetCSLevel ()
 Return CS level. More...
static void IncCSLevel ()
 Increment CS level. More...
- Static Public Member Functions inherited from TObject
static Long_t GetDtorOnly ()
 Return destructor only flag. More...
static Bool_t GetObjectStat ()
 Get status of object stat flag. More...
static void SetDtorOnly (void *obj)
 Set destructor only flag. More...
static void SetObjectStat (Bool_t stat)
 Turn on/off tracking of objects in the TObjectTable. More...

Public Attributes

Double_t fBBVertex [8][3]
Int_t fColor
Bool_t fLocalFrame
Double_t fLocalMaster [16]
UInt_t fPhysicalID
Bool_t fReflection
Short_t fTransparency

Private Member Functions

 TBuffer3D (const TBuffer3D &)
void Init ()
 Initialise buffer. More...
const TBuffer3Doperator= (const TBuffer3D &)

Private Attributes

UInt_t fNbPnts
UInt_t fNbPols
UInt_t fNbSegs
UInt_t fPntsCapacity
UInt_t fPolsCapacity
UInt_t fSections
UInt_t fSegsCapacity
const Int_t fType

Static Private Attributes

static UInt_t fgCSLevel = 0

Additional Inherited Members

- Protected Member Functions inherited from TObject
virtual void DoError (int level, const char *location, const char *fmt, va_list va) const
 Interface to ErrorHandler (protected). More...
void MakeZombie ()

#include <TBuffer3D.h>

Inheritance diagram for TBuffer3D:

Member Enumeration Documentation

◆ EBoolOpCode


Definition at line 43 of file TBuffer3D.h.

◆ ESection


Definition at line 49 of file TBuffer3D.h.

Constructor & Destructor Documentation

◆ TBuffer3D() [1/2]

TBuffer3D::TBuffer3D ( const TBuffer3D )

◆ TBuffer3D() [2/2]

TBuffer3D::TBuffer3D ( Int_t  type,
UInt_t  reqPnts = 0,
UInt_t  reqPntsCapacity = 0,
UInt_t  reqSegs = 0,
UInt_t  reqSegsCapacity = 0,
UInt_t  reqPols = 0,
UInt_t  reqPolsCapacity = 0 


Construct from supplied shape type and raw sizes

Definition at line 222 of file TBuffer3D.cxx.

◆ ~TBuffer3D()

TBuffer3D::~TBuffer3D ( )


Definition at line 235 of file TBuffer3D.cxx.

Member Function Documentation

◆ ClearSectionsValid()

void TBuffer3D::ClearSectionsValid ( )

Clear any sections marked valid.

Definition at line 286 of file TBuffer3D.cxx.

◆ DecCSLevel()

UInt_t TBuffer3D::DecCSLevel ( )

Decrement CS level.

Definition at line 512 of file TBuffer3D.cxx.

◆ GetCSLevel()

UInt_t TBuffer3D::GetCSLevel ( )

Return CS level.

Definition at line 496 of file TBuffer3D.cxx.

◆ GetSections()

UInt_t TBuffer3D::GetSections ( UInt_t  mask) const

Definition at line 68 of file TBuffer3D.h.

◆ IncCSLevel()

void TBuffer3D::IncCSLevel ( )

Increment CS level.

Definition at line 504 of file TBuffer3D.cxx.

◆ Init()

void TBuffer3D::Init ( )

Initialise buffer.

Definition at line 245 of file TBuffer3D.cxx.

◆ NbPnts()

UInt_t TBuffer3D::NbPnts ( ) const

Definition at line 80 of file TBuffer3D.h.

◆ NbPols()

UInt_t TBuffer3D::NbPols ( ) const

Definition at line 82 of file TBuffer3D.h.

◆ NbSegs()

UInt_t TBuffer3D::NbSegs ( ) const

Definition at line 81 of file TBuffer3D.h.

◆ operator=()

const TBuffer3D& TBuffer3D::operator= ( const TBuffer3D )

◆ SectionsValid()

Bool_t TBuffer3D::SectionsValid ( UInt_t  mask) const

Definition at line 67 of file TBuffer3D.h.

◆ SetAABoundingBox()

void TBuffer3D::SetAABoundingBox ( const Double_t  origin[3],
const Double_t  halfLengths[3] 

Set fBBVertex in kBoundingBox section to a axis aligned (local) BB using supplied origin and box half lengths.

/| /|
3-------2 |
| 4-----|-5
|/ |/

Definition at line 320 of file TBuffer3D.cxx.

◆ SetLocalMasterIdentity()

void TBuffer3D::SetLocalMasterIdentity ( )

Set kRaw tessellation section of buffer with supplied sizes.

Set fLocalMaster in section kCore to identity

Definition at line 296 of file TBuffer3D.cxx.

◆ SetRawSizes()

Bool_t TBuffer3D::SetRawSizes ( UInt_t  reqPnts,
UInt_t  reqPntsCapacity,
UInt_t  reqSegs,
UInt_t  reqSegsCapacity,
UInt_t  reqPols,
UInt_t  reqPolsCapacity 

Set kRaw tessellation section of buffer with supplied sizes.

Definition at line 359 of file TBuffer3D.cxx.

◆ SetSectionsValid()

void TBuffer3D::SetSectionsValid ( UInt_t  mask)

Definition at line 65 of file TBuffer3D.h.

◆ Type()

Int_t TBuffer3D::Type ( ) const

Definition at line 85 of file TBuffer3D.h.

Member Data Documentation

◆ fBBVertex

Double_t TBuffer3D::fBBVertex[8][3]

Definition at line 107 of file TBuffer3D.h.

◆ fColor

Int_t TBuffer3D::fColor

Definition at line 88 of file TBuffer3D.h.

◆ fgCSLevel

UInt_t TBuffer3D::fgCSLevel = 0

Definition at line 39 of file TBuffer3D.h.

◆ fID

TObject* TBuffer3D::fID

Definition at line 87 of file TBuffer3D.h.

◆ fLocalFrame

Bool_t TBuffer3D::fLocalFrame

Definition at line 90 of file TBuffer3D.h.

◆ fLocalMaster

Double_t TBuffer3D::fLocalMaster[16]

Definition at line 92 of file TBuffer3D.h.

◆ fNbPnts

UInt_t TBuffer3D::fNbPnts

Definition at line 22 of file TBuffer3D.h.

◆ fNbPols

UInt_t TBuffer3D::fNbPols

Definition at line 24 of file TBuffer3D.h.

◆ fNbSegs

UInt_t TBuffer3D::fNbSegs

Definition at line 23 of file TBuffer3D.h.

◆ fPhysicalID

UInt_t TBuffer3D::fPhysicalID

Definition at line 118 of file TBuffer3D.h.

◆ fPnts

Double_t* TBuffer3D::fPnts

Definition at line 112 of file TBuffer3D.h.

◆ fPntsCapacity

UInt_t TBuffer3D::fPntsCapacity

Definition at line 26 of file TBuffer3D.h.

◆ fPols

Int_t* TBuffer3D::fPols

Definition at line 114 of file TBuffer3D.h.

◆ fPolsCapacity

UInt_t TBuffer3D::fPolsCapacity

Definition at line 28 of file TBuffer3D.h.

◆ fReflection

Bool_t TBuffer3D::fReflection

Definition at line 91 of file TBuffer3D.h.

◆ fSections

UInt_t TBuffer3D::fSections

Definition at line 30 of file TBuffer3D.h.

◆ fSegs

Int_t* TBuffer3D::fSegs

Definition at line 113 of file TBuffer3D.h.

◆ fSegsCapacity

UInt_t TBuffer3D::fSegsCapacity

Definition at line 27 of file TBuffer3D.h.

◆ fTransparency

Short_t TBuffer3D::fTransparency

Definition at line 89 of file TBuffer3D.h.

◆ fType

const Int_t TBuffer3D::fType

Definition at line 20 of file TBuffer3D.h.

Libraries for TBuffer3D:

The documentation for this class was generated from the following files: