1 // Created on: 2012-01-26
2 // Created by: Kirill GAVRILOV
3 // Copyright (c) 2012-2012 OPEN CASCADE SAS
5 // The content of this file is subject to the Open CASCADE Technology Public
6 // License Version 6.5 (the "License"). You may not use the content of this file
7 // except in compliance with the License. Please obtain a copy of the License
8 // at http://www.opencascade.org and read it completely before using this file.
10 // The Initial Developer of the Original Code is Open CASCADE S.A.S., having its
11 // main offices at: 1, place des Freres Montgolfier, 78280 Guyancourt, France.
13 // The Original Code and all software distributed under the License is
14 // distributed on an "AS IS" basis, without warranty of any kind, and the
15 // Initial Developer hereby disclaims all such warranties, including without
16 // limitation, any warranties of merchantability, fitness for a particular
17 // purpose or non-infringement. Please see the License for the specific terms
18 // and conditions governing the rights and limitations under the License.
21 #ifndef _OpenGl_Context_H__
22 #define _OpenGl_Context_H__
24 #include <Aspect_Handle.hxx>
25 #include <Aspect_Drawable.hxx>
26 #include <Aspect_Display.hxx>
27 #include <Aspect_RenderingContext.hxx>
28 #include <Standard_Transient.hxx>
29 #include <TCollection_AsciiString.hxx>
30 #include <Handle_OpenGl_Context.hxx>
32 //! Forward declarations
33 struct OpenGl_GlCore12;
34 struct OpenGl_GlCore13;
35 struct OpenGl_GlCore14;
36 struct OpenGl_GlCore15;
37 struct OpenGl_GlCore20;
41 //! This class generalize access to the GL context and available extensions.
43 //! Functions are grouped into structures and accessed as fields.
44 //! You should check the group for NULL before usage (if group is not NULL
45 //! then all functions are available):
47 //! if (myContext->core20 != NULL)
49 //! myGlProgram = myContext->core20->glCreateProgram();
50 //! .. do more stuff ..
54 //! .. compatibility with outdated configurations ..
58 //! Current implementation provide access to OpenGL core functionality up to 2.0 version
59 //! (core12, core13, core14, core15, fields core20).
60 //! within several extensions (arbVBO, extFBO, etc.).
62 //! Simplified extensions classification:
63 //! - prefixed with NV, AMD, ATI are vendor-specific (however may be provided by other vendors in some cases);
64 //! - prefixed with EXT are accepted by 2+ vendors;
65 //! - prefixed with ARB are accepted by Architecture Review Board and are candidates
66 //! for inclusion into GL core functionality.
67 //! Some functionality can be represented in several extensions simultaneously.
68 //! In this case developer should be careful because different specification may differ
69 //! in aspects (like enumeration values and error-handling).
71 //! Notice that some systems provide mechanisms to simultaneously incorporate with GL contexts
72 //! with different capabilities. Thats why OpenGl_Context should be initialized and used
73 //! for each GL context individually.
74 class OpenGl_Context : public Standard_Transient
78 //! Empty constructor. You should call Init() to perform initialization with bound GL context.
79 Standard_EXPORT OpenGl_Context();
82 Standard_EXPORT virtual ~OpenGl_Context();
84 //! Initialize available extensions.
85 //! GL context should be active!
86 Standard_EXPORT Standard_Boolean Init();
88 #if (defined(_WIN32) || defined(__WIN32__))
89 Standard_EXPORT Standard_Boolean Init (const Aspect_Handle theWindow,
90 const Aspect_Handle theWindowDC,
91 const Aspect_RenderingContext theGContext);
93 Standard_EXPORT Standard_Boolean Init (const Aspect_Drawable theWindow,
94 const Aspect_Display theDisplay,
95 const Aspect_RenderingContext theGContext);
98 //! Check if theExtName extension is supported by active GL context.
99 Standard_EXPORT Standard_Boolean CheckExtension (const char* theExtName) const;
101 //! Auxiliary template to retrieve GL function pointer.
102 //! Pointer to function retrieved from library is statically casted
103 //! to requested type - there no way to check real signature of exported function.
104 //! The context should be bound before call.
105 template <typename FuncType_t>
106 Standard_Boolean FindProc (const char* theFuncName,
107 FuncType_t& theFuncPtr)
109 theFuncPtr = (FuncType_t )findProc (theFuncName);
110 return (theFuncPtr != NULL);
113 //! @return true if detected GL version is greater or equal to requested one.
114 inline Standard_Boolean IsGlGreaterEqual (const Standard_Integer theVerMajor,
115 const Standard_Integer theVerMinor)
117 return (myGlVerMajor > theVerMajor)
118 || (myGlVerMajor == theVerMajor && myGlVerMinor >= theVerMinor);
121 //! Clean up errors stack for this GL context (glGetError() in loop).
122 Standard_EXPORT void ResetErrors();
124 //! Activates current context.
125 //! Class should be initialized with appropriate info.
126 Standard_EXPORT Standard_Boolean MakeCurrent();
128 //! Return true if active mode is GL_FEEDBACK (cached state)
129 Standard_EXPORT Standard_Boolean IsFeedback() const;
131 //! Setup feedback mode cached state
132 Standard_EXPORT void SetFeedback (const Standard_Boolean theFeedbackOn);
134 //! This function retrieves information from GL about free GPU memory that is:
135 //! - OS-dependent. On some OS it is per-process and on others - for entire system.
136 //! - Vendor-dependent. Currently available only on NVIDIA and AMD/ATi drivers only.
137 //! - Numbers meaning may vary.
138 //! You should use this info only for diagnostics purposes.
139 //! @return free GPU dedicated memory in bytes.
140 Standard_EXPORT Standard_Size AvailableMemory() const;
142 //! This function retrieves information from GL about GPU memory
143 //! and contains more vendor-specific values than AvailableMemory().
144 Standard_EXPORT TCollection_AsciiString MemoryInfo() const;
148 //! Wrapper to system function to retrieve GL function pointer by name.
149 Standard_EXPORT void* findProc (const char* theFuncName);
151 //! Read OpenGL version information from active context.
152 Standard_EXPORT void readGlVersion();
154 //! Private initialization function that should be called only once.
155 Standard_EXPORT void init();
157 public: // core profiles
159 OpenGl_GlCore12* core12;
160 OpenGl_GlCore13* core13;
161 OpenGl_GlCore14* core14;
162 OpenGl_GlCore15* core15;
163 OpenGl_GlCore20* core20;
165 public: // extensions
167 OpenGl_ArbVBO* arbVBO; //!< GL_ARB_vertex_buffer_object
168 OpenGl_ExtFBO* extFBO; //!< GL_EXT_framebuffer_object
169 Standard_Boolean atiMem; //!< GL_ATI_meminfo
170 Standard_Boolean nvxMem; //!< GL_NVX_gpu_memory_info
174 #if (defined(_WIN32) || defined(__WIN32__))
175 Aspect_Handle myWindow; //!< window handle (owner of GL context) : HWND
176 Aspect_Handle myWindowDC; //!< Device Descriptor handle : HDC
177 Aspect_RenderingContext myGContext; //!< Rendering Context handle : HGLRC
179 Aspect_Drawable myWindow; //!< window handle (owner of GL context) : GLXDrawable
180 Aspect_Display myDisplay; //!< connection to the X-server : Display*
181 Aspect_RenderingContext myGContext; //!< X-GLX rendering context : GLXContext
184 void* myGlLibHandle; //!< optional handle to GL library
185 OpenGl_GlCore20* myGlCore20; //!< common structure for GL core functions upto 2.0
186 Standard_Integer myGlVerMajor; //!< cached GL version major number
187 Standard_Integer myGlVerMinor; //!< cached GL version minor number
188 Standard_Boolean myIsFeedback; //!< flag indicates GL_FEEDBACK mode
189 Standard_Boolean myIsInitialized; //!< flag indicates initialization state
193 DEFINE_STANDARD_RTTI(OpenGl_Context) // Type definition
197 #endif // _OpenGl_Context_H__