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Reference Guide
TGLSelectBuffer.cxx
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1 // @(#)root/gl:$Id$
2 // Author: Matevz Tadel, Feb 2007
3 
4 /*************************************************************************
5  * Copyright (C) 1995-2004, Rene Brun and Fons Rademakers. *
6  * All rights reserved. *
7  * *
8  * For the licensing terms see $ROOTSYS/LICENSE. *
9  * For the list of contributors see $ROOTSYS/README/CREDITS. *
10  *************************************************************************/
11 
12 #include "TGLSelectBuffer.h"
13 #include "TGLSelectRecord.h"
14 #include <TMath.h>
15 
16 #include <algorithm>
17 
18 /** \class TGLSelectBuffer
19 \ingroup opengl
20 Encapsulates OpenGL select buffer.
21 Provides sorting of the results based on z-coordinate of the
22 selection hit and can fill the TGLSelectRecordBase records.
23 */
24 
25 Int_t TGLSelectBuffer::fgMaxBufSize = 1 << 20; // 1MByte
26 
27 ////////////////////////////////////////////////////////////////////////////////
28 /// Constructor.
29 
31  fBufSize (1024),
32  fBuf (new UInt_t [fBufSize]),
33  fNRecords (-1)
34 {
35 }
36 
37 ////////////////////////////////////////////////////////////////////////////////
38 /// Destructor.
39 
41 {
42  delete [] fBuf;
43 }
44 
45 ////////////////////////////////////////////////////////////////////////////////
46 ///static: return true if current buffer is smaller than the max buffer size
47 
49 {
50  return fBufSize < fgMaxBufSize;
51 }
52 
53 ////////////////////////////////////////////////////////////////////////////////
54 /// Increase size of the select buffer.
55 
57 {
58  delete [] fBuf;
60  fBuf = new UInt_t[fBufSize];
61 }
62 
63 ////////////////////////////////////////////////////////////////////////////////
64 /// Process result of GL-selection: sort the hits by their minimum
65 /// z-coordinate.
66 
68 {
69  // The '-1' case should be handled on the caller side.
70  // Here we just assume no hits were recorded.
71 
72  if (glResult < 0)
73  glResult = 0;
74 
75  fNRecords = glResult;
76  fSortedRecords.resize(fNRecords);
77 
78  if (fNRecords > 0)
79  {
80  Int_t i;
81  UInt_t* buf = fBuf;
82  for (i = 0; i < fNRecords; ++i)
83  {
84  fSortedRecords[i].first = buf[1]; // minimum depth
85  fSortedRecords[i].second = buf; // record address
86  buf += 3 + buf[0];
87  }
88  std::sort(fSortedRecords.begin(), fSortedRecords.end());
89  }
90 }
91 
92 ////////////////////////////////////////////////////////////////////////////////
93 /// Fill select record rec with data on (sorted) position i.
94 /// Returns depth of name-stack for this record.
95 
97 {
98  rec.Set(fSortedRecords[i].second);
99  return rec.GetN();
100 }
void ProcessResult(Int_t glResult)
Process result of GL-selection: sort the hits by their minimum z-coordinate.
TGLSelectBuffer()
Constructor.
Int_t SelectRecord(TGLSelectRecordBase &rec, Int_t i)
Fill select record rec with data on (sorted) position i.
static Int_t fgMaxBufSize
Short_t Min(Short_t a, Short_t b)
Definition: TMathBase.h:168
int Int_t
Definition: RtypesCore.h:41
bool Bool_t
Definition: RtypesCore.h:59
Base class for select records.
Bool_t CanGrow()
static: return true if current buffer is smaller than the max buffer size
virtual void Set(UInt_t *data)
Setup the record from raw buffer.
unsigned int UInt_t
Definition: RtypesCore.h:42
vRawRecord_t fSortedRecords
Int_t GetN() const
void Grow()
Increase size of the select buffer.
virtual ~TGLSelectBuffer()
Destructor.