5e27df78 |
1 | // Created by: Kirill GAVRILOV |
d5f74e42 |
2 | // Copyright (c) 2013-2014 OPEN CASCADE SAS |
5e27df78 |
3 | // |
973c2be1 |
4 | // This file is part of Open CASCADE Technology software library. |
5e27df78 |
5 | // |
d5f74e42 |
6 | // This library is free software; you can redistribute it and/or modify it under |
7 | // the terms of the GNU Lesser General Public License version 2.1 as published |
973c2be1 |
8 | // by the Free Software Foundation, with special exception defined in the file |
9 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
10 | // distribution for complete text of the license and disclaimer of any warranty. |
5e27df78 |
11 | // |
973c2be1 |
12 | // Alternatively, this file may be used under the terms of Open CASCADE |
13 | // commercial license or contractual agreement. |
5e27df78 |
14 | |
15 | #ifndef _OpenGl_VertexBufferEditor_H__ |
16 | #define _OpenGl_VertexBufferEditor_H__ |
17 | |
18 | #include <OpenGl_VertexBuffer.hxx> |
19 | #include <OpenGl_Context.hxx> |
20 | |
21 | #include <NCollection_Array1.hxx> |
22 | |
23 | //! Auxiliary class to iteratively modify data of existing VBO. |
24 | //! It provides iteration interface with delayed CPU->GPU memory transfer to avoid slow per-element data transfer. |
25 | //! User should explicitly call Flush() method to ensure that all data is transferred to VBO. |
26 | //! Temporary buffer on CPU side can be initialized with lesser capacity than VBO |
27 | //! to allow re-usage of shared buffer with fixed size between VBOs. |
28 | //! |
29 | //! You should use NCollection_Vec2/NCollection_Vec3/NCollection_Vec4 with appropriate length |
30 | //! to instantiate this template and access elements in VBO. |
31 | //! |
32 | //! Notice that this technique designed for VBO streaming scenarios (when VBO is modified from time to time). |
33 | //! Also this class doesn't retrieve existing data from VBO - data transferred only in one direction! |
34 | //! In case of static data this is preferred to upload it within one call during VBO initialization. |
35 | template<typename theVec_t> |
36 | class OpenGl_VertexBufferEditor |
37 | { |
38 | |
39 | public: |
40 | |
41 | //! Creates empty editor |
42 | //! theTmpBufferLength - temporary buffer length |
43 | OpenGl_VertexBufferEditor (const Standard_Integer theTmpBufferLength = 0) |
44 | : myElemFrom (0), |
45 | myElemsNb (0), |
46 | myTmpBuffer (0, theTmpBufferLength > 0 ? (theTmpBufferLength - 1) : 2047) {} |
47 | |
48 | //! Creates empty editor |
49 | //! theTmpBuffer - pointer to temporary buffer |
50 | //! theTmpBufferLength - temporary buffer length |
51 | OpenGl_VertexBufferEditor (theVec_t* theTmpBuffer, |
52 | const Standard_Integer theTmpBufferLength) |
53 | : myElemFrom (0), |
54 | myElemsNb (0), |
55 | myTmpBuffer (theTmpBuffer[0], 0, theTmpBufferLength - 1) {} |
56 | |
57 | //! Initialize editor for specified VBO. |
58 | //! theGlCtx - bound OpenGL context to edit VBO |
59 | //! theVbo - VBO to edit |
60 | Standard_Boolean Init (const Handle(OpenGl_Context)& theGlCtx, |
61 | const Handle(OpenGl_VertexBuffer)& theVbo) |
62 | { |
63 | myGlCtx = theGlCtx; |
64 | myVbo = theVbo; |
65 | if (myGlCtx.IsNull() || myVbo.IsNull() || !myVbo->IsValid() || myVbo->GetComponentsNb() != GLuint (theVec_t::Length())) |
66 | { |
67 | return Standard_False; |
68 | } |
69 | |
70 | myElemFrom = myElemsNb = 0; |
71 | return Standard_True; |
72 | } |
73 | |
74 | //! Modify current element in VBO. |
75 | theVec_t& Value() |
76 | { |
a174a3c5 |
77 | return myTmpBuffer.ChangeValue (myElemsNb); |
5e27df78 |
78 | } |
79 | |
80 | //! Move to the next position in VBO. |
81 | Standard_Boolean Next() |
82 | { |
a174a3c5 |
83 | if (++myElemsNb > myTmpBuffer.Upper()) |
84 | { |
85 | return Flush(); |
86 | } |
87 | return Standard_True; |
5e27df78 |
88 | } |
89 | |
90 | //! Push current data from local buffer to VBO. |
91 | Standard_Boolean Flush() |
92 | { |
a174a3c5 |
93 | if (myElemsNb <= 0) |
94 | { |
5e27df78 |
95 | return Standard_True; |
a174a3c5 |
96 | } |
97 | |
98 | if (myVbo.IsNull() |
99 | || !myVbo->SubData (myGlCtx, myElemFrom, myElemsNb, &myTmpBuffer.Value (0)[0])) |
100 | { |
101 | // should never happens |
102 | return Standard_False; |
103 | } |
104 | myElemFrom += myElemsNb; |
105 | myElemsNb = 0; |
106 | |
107 | return Standard_True; |
5e27df78 |
108 | } |
109 | |
99d99a6d |
110 | //! @return assigned VBO |
111 | inline const Handle(OpenGl_VertexBuffer)& GetVBO() const |
112 | { |
113 | return myVbo; |
114 | } |
115 | |
5e27df78 |
116 | private: |
117 | |
118 | Handle(OpenGl_Context) myGlCtx; //!< handle to current OpenGL context |
119 | Handle(OpenGl_VertexBuffer) myVbo; //!< edited VBO |
120 | Standard_Integer myElemFrom; //!< element in VBO to upload from |
121 | Standard_Integer myElemsNb; //!< current element in temporary buffer |
122 | NCollection_Array1<theVec_t> myTmpBuffer; //!< temporary array |
123 | |
124 | }; |
125 | |
126 | #endif // _OpenGl_VertexBufferEditor_H__ |