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alice_vsd.C File Reference

Detailed Description

Complex example showing ALICE VSD visualization.

alice_vsd.C - a simple event-display for ALICE

Only standard ROOT is used to process the ALICE VSD files.

No ALICE code is needed – the VSD file is exported from AliRoot into VSD format – see TEveVSDStructs.h and TEveVSD.h.

A simple geometry of 10KB, extracted from the full TGeo-geometry, is used to outline the central detectors of ALICE.

All files are access from the web by using the "CACHEREAD" option.

#include <TEveManager.h>
#include <TEveVSD.h>
#include <TEveVSDStructs.h>
#include <TEveTrack.h>
#include <TEveGeoShape.h>
#include <TGTab.h>
#include <TGButton.h>
#include <TFile.h>
#include <TKey.h>
#include <TSystem.h>
#include <TPRegexp.h>
// Include components -- compile time link :)
#include "MultiView.C"
MultiView* gMultiView = nullptr;
class TVSDReader
// ----------------------------------------------------------
// File / Event Data
// ----------------------------------------------------------
TFile *fFile;
TDirectory *fDirectory;
TObjArray *fEvDirKeys;
Int_t fMaxEv, fCurEv;
// ----------------------------------------------------------
// Event visualization structures
// ----------------------------------------------------------
TEveTrackList *fTrackList;
TEvePointSet *fITSClusters;
TEvePointSet *fTPCClusters;
TEvePointSet *fTRDClusters;
TEvePointSet *fTOFClusters;
TVSDReader(const char* file_name) :
fFile(nullptr), fDirectory(nullptr), fEvDirKeys(nullptr),
fMaxEv(-1), fCurEv(-1),
fITSClusters(nullptr), fTPCClusters(nullptr), fTRDClusters(nullptr), fTOFClusters(nullptr)
fFile = TFile::Open(file_name);
if (!fFile)
Error("VSD_Reader", "Can not open file '%s' ... terminating.",
fEvDirKeys = new TObjArray;
TPMERegexp name_re("Event\\d+");
TObjLink* lnk = fFile->GetListOfKeys()->FirstLink();
while (lnk) {
if (name_re.Match(lnk->GetObject()->GetName()))
lnk = lnk->Next();
fMaxEv = fEvDirKeys->GetEntriesFast();
if (fMaxEv == 0) {
Error("VSD_Reader", "No events to show ... terminating.");
fVSD = new TEveVSD;
virtual ~TVSDReader()
// Destructor.
delete fVSD;
delete fEvDirKeys;
delete fFile;
void AttachEvent()
// Attach event data from current directory.
void DropEvent()
// Drup currently held event data, release current directory.
// Drop old visualization structures.
// Drop old event-data.
delete fDirectory;
fDirectory = nullptr;
// Event navigation
void NextEvent()
GotoEvent(fCurEv + 1);
void PrevEvent()
GotoEvent(fCurEv - 1);
Bool_t GotoEvent(Int_t ev)
if (ev < 0 || ev >= fMaxEv)
Warning("GotoEvent", "Invalid event id %d.", ev);
return kFALSE;
// Connect to new event-data.
fCurEv = ev;
fDirectory = (TDirectory*) ((TKey*) fEvDirKeys->At(fCurEv))->ReadObj();
// Load event data into visualization structures.
LoadClusters(fITSClusters, "ITS", 0);
LoadClusters(fTPCClusters, "TPC", 1);
LoadClusters(fTRDClusters, "TRD", 2);
LoadClusters(fTOFClusters, "TOF", 3);
// Fill projected views.
auto top = gEve->GetCurrentEvent();
return kTRUE;
// Cluster loading
void LoadClusters(TEvePointSet*& ps, const TString& det_name, Int_t det_id)
if (ps == nullptr) {
ps = new TEvePointSet(det_name);
ps->SetMainColor((Color_t)(det_id + 2));
} else {
TEvePointSelector ss(fVSD->fTreeC, ps, "fV.fX:fV.fY:fV.fZ",
TString::Format("fDetId==%d", det_id));
ps->SetTitle(TString::Format("N=%d", ps->Size()));
// Track loading
enum ESDTrackFlags
Bool_t trackIsOn(TEveTrack* t, Int_t mask)
// Check is track-flag specified by mask are set.
return (t->GetStatus() & mask) > 0;
void LoadEsdTracks()
// Read reconstructed tracks from current event.
if (fTrackList == nullptr) {
fTrackList = new TEveTrackList("ESD Tracks");
} else {
auto trkProp = fTrackList->GetPropagator();
// !!!! Need to store field on file !!!!
// Can store TEveMagField ?
Int_t nTracks = fVSD->fTreeR->GetEntries();
for (Int_t n = 0; n < nTracks; ++n) {
TEveTrack* track = new TEveTrack(&fVSD->fR, trkProp);
track->SetName(Form("ESD Track %d", fVSD->fR.fIndex));
ClassDef(TVSDReader, 0);
TVSDReader* gVSDReader = nullptr;
// Forward declaration.
void make_gui();
void alice_vsd(const char* vsd_file_name=
// Main function, initializes the application.
// 1. Load the auto-generated library holding ESD classes and
// ESD dictionaries.
// 2. Open ESD data-files.
// 3. Load cartoon geometry.
// 4. Spawn simple GUI.
// 5. Load first event.
gVSDReader = new TVSDReader(vsd_file_name);
TEveGeoShape *gentle_geom = nullptr;
{ // Simple geometry
auto geom =
if (!geom)
auto gse = (TEveGeoShapeExtract*) geom->Get("Gentle");
gentle_geom = TEveGeoShape::ImportShapeExtract(gse, nullptr);
delete geom;
// Standard multi-view
gMultiView = new MultiView;
// Final stuff
gEve->AddEvent(new TEveEventManager("Event", "ALICE VSD Event"));
gEve->Redraw3D(kTRUE); // Reset camera after the first event has been shown.
void make_gui()
// Create minimal GUI for event navigation.
auto browser = gEve->GetBrowser();
auto frmMain = new TGMainFrame(gClient->GetRoot(), 1000, 600);
frmMain->SetWindowName("XX GUI");
auto hf = new TGHorizontalFrame(frmMain);
TString icondir(TString::Format("%s/icons/", gSystem->Getenv("ROOTSYS")));
TGPictureButton* b = nullptr;
b = new TGPictureButton(hf, gClient->GetPicture(icondir+"GoBack.gif"));
b->Connect("Clicked()", "TVSDReader", gVSDReader, "PrevEvent()");
b = new TGPictureButton(hf, gClient->GetPicture(icondir+"GoForward.gif"));
b->Connect("Clicked()", "TVSDReader", gVSDReader, "NextEvent()");
browser->SetTabTitle("Event Control", 0);
Multi-view (3d, rphi, rhoz) service class using EVE Window Manager.
#define b(i)
Definition RSha256.hxx:100
bool Bool_t
Definition RtypesCore.h:63
int Int_t
Definition RtypesCore.h:45
short Color_t
Definition RtypesCore.h:92
constexpr Bool_t kFALSE
Definition RtypesCore.h:101
constexpr Bool_t kTRUE
Definition RtypesCore.h:100
#define ClassDef(name, id)
Definition Rtypes.h:337
@ kYellow
Definition Rtypes.h:66
void Error(const char *location, const char *msgfmt,...)
Use this function in case an error occurred.
Definition TError.cxx:185
void Warning(const char *location, const char *msgfmt,...)
Use this function in warning situations.
Definition TError.cxx:229
R__EXTERN TEveManager * gEve
#define gClient
Definition TGClient.h:157
@ kDeepCleanup
Definition TGFrame.h:42
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void char Point_t Rectangle_t WindowAttributes_t Float_t Float_t Float_t Int_t Int_t UInt_t UInt_t Rectangle_t mask
char * Form(const char *fmt,...)
Formats a string in a circular formatting buffer.
Definition TString.cxx:2467
R__EXTERN TSystem * gSystem
Definition TSystem.h:560
TList * GetListOfKeys() const override
Describe directory structure in memory.
Definition TDirectory.h:45
virtual void AddElement(TEveElement *el)
Add el to the list of children.
virtual void SetMainColor(Color_t color)
Set main color of the element.
void IncDenyDestroy()
Increases the deny-destroy count of the element.
virtual void DestroyElements()
Destroy all children of this element.
Base class for event management and navigation.
Globally positioned TGeoShape with rendering attributes and an optional list of daughter shape-extrac...
Wrapper for TGeoShape with absolute positioning and color attributes allowing display of extracted TG...
static TEveGeoShape * ImportShapeExtract(TEveGeoShapeExtract *gse, TEveElement *parent=nullptr)
Import a shape extract 'gse' under element 'parent'.
void AddElement(TEveElement *element, TEveElement *parent=nullptr)
Add an element.
void AddGlobalElement(TEveElement *element, TEveElement *parent=nullptr)
Add a global element, i.e.
TEveViewerList * GetViewers() const
TGLViewer * GetDefaultGLViewer() const
Get TGLViewer of the default TEveViewer.
TEveBrowser * GetBrowser() const
static TEveManager * Create(Bool_t map_window=kTRUE, Option_t *opt="FIV")
If global TEveManager* gEve is not set initialize it.
TGListTreeItem * AddEvent(TEveEventManager *event)
Add a new event and make it the current event.
void Redraw3D(Bool_t resetCameras=kFALSE, Bool_t dropLogicals=kFALSE)
TEveEventManager * GetCurrentEvent() const
TEvePointSelector is a sub-class of TSelectorDraw for direct extraction of point-like data from a Tre...
TEvePointSet is a render-element holding a collection of 3D points with optional per-point TRef and a...
virtual void SetTitle(const char *t)
void Reset(Int_t n_points=0, Int_t n_int_ids=0)
Drop all data and set-up the data structures to recive new data.
void SetMarkerStyle(Style_t mstyle=1) override
Set marker style, propagate to projecteds.
void SetMarkerSize(Size_t msize=1) override
Set marker size, propagate to projecteds.
A list of tracks supporting change of common attributes and selection based on track parameters.
Definition TEveTrack.h:140
void SetMarkerStyle(Style_t s) override
Set marker style for the list and the elements.
void SetMarkerColor(Color_t c) override
Set marker color for the list and the elements.
void SetMainColor(Color_t c) override
Set main (line) color for the list and the elements.
void SetMarkerSize(Size_t s) override
Set marker size for the list and the elements.
void MakeTracks(Bool_t recurse=kTRUE)
Regenerate the visual representations of tracks.
TEveTrackPropagator * GetPropagator()
Definition TEveTrack.h:175
void SetMagField(Double_t bX, Double_t bY, Double_t bZ)
Set constant magnetic field and rebuild tracks.
Visual representation of a track.
Definition TEveTrack.h:33
void SetAttLineAttMarker(TEveTrackList *tl)
Set line and marker attributes from TEveTrackList.
Int_t GetStatus() const
Definition TEveTrack.h:104
virtual void SetStdTitle()
Set standard track title based on most data-member values.
Visualization Summary Data - a collection of trees holding standard event data in experiment independ...
Definition TEveVSD.h:20
static void DisableTObjectStreamersForVSDStruct()
Disable TObject streamers for those VSD structs that inherit from TObject directly.
Definition TEveVSD.cxx:203
TEveRecTrack fR
Definition TEveVSD.h:44
virtual void SetBranchAddresses()
Set branche addresses of internal trees.
Definition TEveVSD.cxx:121
virtual void DeleteTrees()
Delete internal trees.
Definition TEveVSD.cxx:87
virtual void SetDirectory(TDirectory *dir)
Set directory in which the trees are (or will be) created.
Definition TEveVSD.cxx:63
TTree * fTreeC
Definition TEveVSD.h:34
virtual void LoadTrees()
Load internal trees from directory.
Definition TEveVSD.cxx:148
TTree * fTreeR
Definition TEveVSD.h:35
void SwitchColorSet()
Switch background color.
void DeleteAnnotations()
Delete annotations from all viewers.
A ROOT file is composed of a header, followed by consecutive data records (TKey instances) with a wel...
Definition TFile.h:53
static Bool_t SetCacheFileDir(ROOT::Internal::TStringView cacheDir, Bool_t operateDisconnected=kTRUE, Bool_t forceCacheread=kFALSE)
Definition TFile.h:332
static TFile * Open(const char *name, Option_t *option="", const char *ftitle="", Int_t compress=ROOT::RCompressionSetting::EDefaults::kUseCompiledDefault, Int_t netopt=0)
Create / open a file.
Definition TFile.cxx:4075
void Close(Option_t *option="") override
Close a file.
Definition TFile.cxx:936
A composite frame that layout their children in horizontal way.
Definition TGFrame.h:385
void SetStyle(Short_t st)
Defines top level windows that interact with the system Window Manager.
Definition TGFrame.h:397
Yield an action as soon as it is clicked.
Definition TGButton.h:228
virtual Bool_t SetTab(Int_t tabIndex, Bool_t emit=kTRUE)
Brings the composite frame with the index tabIndex to the front and generate the following event if t...
Definition TGTab.cxx:558
Book space in a file, create I/O buffers, to fill them, (un)compress them.
Definition TKey.h:28
virtual TObjLink * FirstLink() const
Definition TList.h:102
An array of TObjects.
Definition TObjArray.h:31
Int_t GetEntriesFast() const
Definition TObjArray.h:58
TObject * At(Int_t idx) const override
Definition TObjArray.h:164
void Add(TObject *obj) override
Definition TObjArray.h:68
virtual const char * GetName() const
Returns name of object.
Definition TObject.cxx:439
Wrapper for PCRE library (Perl Compatible Regular Expressions).
Definition TPRegexp.h:97
virtual Int_t Size() const
virtual void SetName(const char *name)
Change (i.e.
void StartEmbedding(Int_t pos=kRight, Int_t subpos=-1) override
Start embedding external frame in the tab "pos" and tab element "subpos".
TGTab * GetTabRight() const
Basic string class.
Definition TString.h:139
static TString Format(const char *fmt,...)
Static method which formats a string using a printf style format descriptor and return a TString.
Definition TString.cxx:2356
virtual const char * Getenv(const char *env)
Get environment variable.
Definition TSystem.cxx:1650
virtual void Exit(int code, Bool_t mode=kTRUE)
Exit the application.
Definition TSystem.cxx:703
virtual Int_t GetEntry(Long64_t entry, Int_t getall=0)
Read all branches of entry and return total number of bytes read.
Definition TTree.cxx:5635
virtual Long64_t GetEntries() const
Definition TTree.h:463
const Int_t n
Definition legend1.C:16
Matevz Tadel

Definition in file alice_vsd.C.