0026859: Export of GDT from XCAF to STEP
[occt.git] / dox / dev_guides / upgrade / upgrade.md
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c6f11ec0 1Upgrade from older OCCT versions {#occt_dev_guides__upgrade}
2================================
3
4@tableofcontents
5
d1a67b9d 6@section upgrade_intro Introduction
c6f11ec0 7
d1a67b9d 8This document provides technical details on changes made in particular versions of OCCT, and is aimed to help upgrading user applications based on previous versions of OCCT to newer ones.
c6f11ec0 9
d1a67b9d 10@subsection upgrade_intro_precautions Precautions
c6f11ec0 11
d1a67b9d 12Back-up your code before upgrade.
13We strongly recommend using version control system during upgrade process, saving one or several commits for each step of upgrade, until overall result is verified.
14This will facilitate identification and correction of possible problems that can occur on intermediate steps of upgrade.
15Carefully document each step to be able to repeat it if necessary.
16
17@subsection upgrade_intro_disclaim Disclaimer
18
19This document describes known issues that have been encountered in porting of OCCT and some applications, and approaches that helped to resolve these issues in known cases.
20It does not pretend to cover all possible migration issues that can appear in your application.
21Please take this document with discretion; apply your expertise and knowledge of your application to ensure correct result.
22
23The automatic upgrade tool is provided as-is, without warranty of any kind, and we explicitly disclaim any liability for possible errors that may appear due to use of this tool.
24It is your responsibility to ensure that the changes you made in your code are correct.
25When upgrading your code by automatic script, make sure to carefully review the changes made by it, on each step, before committing them.
26
27@section upgrade_700 Upgrade to OCCT 7.0.0
28
29@subsection upgrade_700_persist Removal of legacy persistence
c6f11ec0 30
31Legacy persistence for shapes and OCAF data based on Storage_Schema (toolkits TKShapeShcema, TLStdLSchema, TKStdSchema, TKXCAFSchema) has been removed in OCCT 7.0.0.
32Applications that used these persistence tools for their data need to be updated to use other persistence mechanisms.
33
d1a67b9d 34The existing data files in standard formats can be converted using OCCT 6.9.0 or previous version, as follows.
c6f11ec0 35
36#### CSFDB files
37
38Files in CSFDB format (usually with extension .csfdb) contain OCCT shape data that can be converted to BRep format.
39The easiest way to do that is to use ImportExport sample provided with OCCT 6.9.0 (or earlier):
40
41- Start ImportExport sample
42- Select File / New
43- Select File / Import / CSFDB... and specify the file to be converted
44- Drag mouse with right button pressed across the view to select all shapes by rectangle
45- Select File / Export / BREP... and specify location and name for the resulting file
46
47#### OCAF and XCAF documents
48
49Files containing OCAF data saved in old format usually have extensions .std or .sgd or .dxc (XDE documents).
50These files can be converted to XML or binary OCAF formats using DRAW Test Harness commands available in OCCT 6.9.0 or earlier.
51
52For that, start *DRAWEXE* and perform the following commands:
53
54 * for the conversion of the "*.std" and "*.sgd" file formats to the binary format "*.cbf" (Created document should be in **BinOcaf** format instead of **MDTV-Standard**):
55
56 @code
57 Draw[]> pload ALL
58 Draw[]> Open [path to *.std or *.sgd file] Doc
59 Draw[]> Format Doc BinOcaf
60 Draw[]> SaveAs Doc [path to the new file]
61 @endcode
62
63 * for the conversion of the "*.dxc" file format to the binary format "*.xbf" (Created document should be in **BinXCAF** format instead of **MDTV-XCAF**):
64
65 @code
66 Draw[]> pload ALL
67 Draw[]> XOpen [path to *.dxc file] Doc
68 Draw[]> Format Doc BinXCAF
69 Draw[]> XSave Doc [path to the new file]
70 @endcode
71
72On Windows, be careful to replace back slashes in the file path by either direct slash or pairs of back slashes.
73Use "XmlOcaf" or "XmlXCAF" instead of "BinOcaf" and "BinXCAF", respectively, to save in XML format instead of binary one.
74
d1a67b9d 75@subsection upgrade_occt700_cdl Removal of CDL and WOK
76
77OCCT code has been completely refactored in version 7.0 to get rid of obsolete technologies used since its inception: CDL (Cas.Cade Definition Language) and WOK (Workshop Organization Kit).
78C++ code previously generated by WOK from CDL declarations is now included directly in OCCT sources.
79
80This modification did not change names, API, and behavior of existing OCCT classes, thus in general the code based on OCCT 6.x should compile and work fine with OCCT 7.0.
81However, due to redesign of basic mechanisms (CDL generic classes, Handles and RTTI) using C++ templates, some changes may be necessary in the code when porting to OCCT 7.0, as described below.
82
83WOK is not necessary anymore for building OCCT from sources, though it still can be used in traditional way -- auxiliary files required for that are preserved.
84The recommended method for building OCCT 7.x is CMake, see @ref occt_dev_guides__building_cmake.
85Alternative solution is to use legacy generator of project files (extracted from WOK), see @ref occt_dev_guides__building_wok.
86
87@subsubsection upgrade_occt700_cdl_auto Automatic upgrade
88
89Most of typical changes required for upgrading code to use OCCT 7.0 can be done automatically using the *upgrade* tool included in OCCT 7.0.
90This tool is a Tcl script, thus Tcl should be available on your workstation to run it.
91
92Example:
93~~~~~
94 $ tclsh
95 % source <path_to_occt>/adm/upgrade.tcl
96 % upgrade -recurse -all -src=<path_to_your_sources>
97~~~~~
98
99On Windows, helper batch script upgrade.bat can be used, provided that Tcl is either available in PATH, or configured via custom.bat script (for instance, if you use OCCT installed from Windows installer package). Start it from command prompt:
100
101~~~~~
102cmd> <path_to_occt>\upgrade.bat -recurse -all -inc=<path_to_occt>\inc -src=<path_to_your_sources> [options]
103~~~~~
104
105Run upgrade tool without arguments to see the list of available options.
106
107Upgrade tool performs the following changes in the code.
108
1091. Adds second argument to macro DEFINE_STANDARD_RTTI indicating base class for its argument class (if inheritance is recognized by the script):
110~~~~~
111DEFINE_STANDARD_RTTI(Class) -> DEFINE_STANDARD_RTTI(Class, Base)
112~~~~~
113
1142. Replaces forward declarations of collection classes previously generated from CDL generics (defined in TCollection package) by \#include of corresponding header:
115~~~~~
116class TColStd_Array1OfReal; -> #include <TColStd_Array1OfReal.hxx>
117~~~~~
118
1193. Replaces underscored names of Handle classes by usage of a macro:
120~~~~~
121Handle_Class -> Handle(Class)
122~~~~~
123 This change is not applied if source or header file is recognized as containing definition of Qt class with signals or slots, to avoid possible compilation errors of MOC files caused by inability of MOC to recognize macros (see http://doc.qt.io/qt-4.8/signalsandslots.html).
124 The file is considered as defining Qt object if it contains strings "Q_OBJECT" and either "slots:" or "signals".
125
1264. Removes forward declarations of classes with names Handle(C) or Handle_C, replacing these either by forward declaration of its argument class, or (for files defining Qt objects) \#include statement for header with name of the argument class and extension .hxx:
127~~~~~
128class Handle(TColStd_HArray1OfReal); -> #include <TColStd_HArray1OfReal.hxx>
129~~~~~
130
1315. Removes \#includes of files Handle_...hxx disappeared in OCCT 7.0:
132~~~~~
133#include <Handle_Geom_Curve.hxx> ->
134~~~~~
135
1366. Removes typedef statements that use Handle macro to generate name:
137~~~~~
138typedef NCollection_Handle<Message_Msg> Handle(Message_Msg); ->
139~~~~~
140
1417. Converts C-style casts applied to Handles to calls to DownCast() method:
142~~~~~
143 ((Handle(A)&)b) -> Handle(A)::DownCast(b)
144 (Handle(A)&)b -> Handle(A)::DownCast(b)
145 (*((Handle(A)*)&b)) -> Handle(A)::DownCast(b)
146 *((Handle(A)*)&b) -> Handle(A)::DownCast(b)
147 (*(Handle(A)*)&b) -> Handle(A)::DownCast(b)
148~~~~~
149
1508. Moves Handle() macro out of namespace scope:
151~~~~~
152Namespace::Handle(Class) -> Handle(Namespace::Class)
153~~~~~
154
1559. Converts local variables of reference type initialized by temporary object returned by call to DownCast(), to non-references (to avoid using reference to destroyed memory):
156~~~~~
157 const Handle(A)& a = Handle(B)::DownCast (b); -> Handle(A) a (Handle(B)::DownCast (b));
158~~~~~
159
16010. Adds \#include for all classes used as argument to macro STANDARD_TYPE(), except of already included ones;
161
16211. Removes uses of obsolete macros IMPLEMENT_DOWNCAST() and IMPLEMENT_STANDARD_*().
163
164 > If you plan to keep compatibility of your code with older versions of OCCT, add option "-compat" to avoid the latter change. See also @ref upgrade_occt700_cdl_compat.
165
166As long as the upgrade routine runs, some information messages are sent to the standard output.
167In some cases the warnings or errors like the following may appear:
168
169~~~~~
170 Error in {HEADER_FILE}: Macro DEFINE_STANDARD_RTTI used for class {CLASS_NAME} whose declaration is not found in this file, cannot fix
171~~~~~
172
173Be sure to check carefully all reported errors and warnings, as corresponding places likely will require manual corrections.
174In some cases these messages may help you to detect errors in your code, for instance, cases where DEFINE_STANDARD_RTTI macro passes invalid class name as an argument.
175
176@subsubsection upgrade_occt700_cdl_compiler Possible compiler errors
177
178Some situations requiring upgrade cannot be detected and / or handled by automatic procedure.
179If you get compiler errors or warnings when trying to build upgraded code, you will need to fix them manually.
180The following paragraphs list known situations of this kind.
181
182#### Missing header files
183
184Use of handle objects (construction, comparison using operators == or !=, use of function STANDRAD_TYPE() and method DownCast()) now requires the type of the object pointed by Handle to be completely known at compile time. Thus it may be necessary to include header of the corresponding class to make the code compilable.
185
186For example, the following lines will fail to compile if Geom_Line.hxx is not included:
187
188~~~~~
189Handle(Geom_Line) aLine = 0;
190if (aLine != aCurve) {...}
191if (aCurve->IsKind(STANDARD_TYPE(Geom_Line)) {...}
192aLine = Handle(Geom_Line)::DownCast (aCurve);
193~~~~~
194
195Note that it is not necessary to include header of the class to declare Handle to it.
196However, if you define a class *B* that uses Handle(*A*) in its fields, or contains a method returning Handle(*A*), it is advisable to have header defining *A* included in the header of *B*.
197This will eliminate the need to include the header *A* in each source file where class *B* is used.
198
199#### Ambiguity of calls to overloaded functions
200
201This issue appears in compilers that do not support default arguments in template functions (known cases are Visual C++ 10 and 11): compiler reports ambiguity error if handle is used in argument of call to function that has two or move overloaded versions, accepting handles to different types.
202The problem is that operator const handle<T2>& is defined for any type T2, thus compiler cannot make a right choice.
203
204Example:
205~~~~~
206void func (const Handle(Geom_Curve)&);
207void func (const Handle(Geom_Surface)&);
208
209Handle(Geom_TrimmedCurve) aCurve = new Geom_TrimmedCurve (...);
210func (aCurve); // ambiguity error in VC++ 10
211~~~~~
212
213To resolve this ambiguity, change your code so that argument type corresponds exactly to the function signature.
214In some cases this can be done by using relevant type for the corresponding variable, like in the example above:
215
216~~~~~
217Handle(Geom_Curve) aCurve = new Geom_TrimmedCurve (...);
218~~~~~
219
220Other variants are assigning the argument to local variable of correct type, using direct cast or constructor:
221
222~~~~~
223const Handle(Geom_Curve)& aGCurve (aTrimmedCurve);
224func (aGCurve); // OK - argument has exact type
225func (static_cast(aCurve)); // OK - direct cast
226func (Handle(Geom_Curve)(aCurve)); // OK - temporary handle is constructed
227~~~~~
228
229Another possibility is defining additional templated variant of the overloaded function causing ambiguity, and use SFINAE to resolve the ambiguity.
230For example of this technique, see definition of the template variant of the method IGESData_IGESWriter::Send().
231
232#### Lack of implicit cast to base type
233
234Due to the fact that now cast of handle to reference to handle to the base type is user-defined operation, conversions that require this cast combined with other user-defined cast will not be resolved automatically by compiler.
235
236For example:
237
238~~~~~
239Handle(Geom_Geometry) aC = GC_MakeLine (p, v); // compiler error
240~~~~~
241
242The problem here is that class GCE2d_MakeSegment has user-defined conversion to const Handle(Geom_TrimmedCurve)&, which is not the same as type of the local variable aC.
243
244To resolve this, use method Value():
245
246~~~~~
247Handle(Geom_Geometry) aC = GC_MakeLine (p, v).Value(); // ok
248~~~~~
249
250or use variable of appropriate type:
251
252~~~~~
253Handle(Geom_TrimmedCurve) aC = GC_MakeLine (p, v); // ok
254~~~~~
255
256#### Incorrect use of STANDARD_TYPE and Handle macros
257
258You might need to clean your code from incorrect use of macros *STANDARD_TYPE*() and *Handle*().
259
2601. Explicit definitions of static functions with names generated by macro STANDARD_TYPE(), which are artifacts of old implementation of RTTI, should be removed.
261
262 Example:
263~~~~~
264const Handle(Standard_Type)& STANDARD_TYPE(math_GlobOptMin)
265{
266 static Handle(Standard_Type) _atype = new Standard_Type ("math_GlobOptMin", sizeof (math_GlobOptMin));
267 return _atype;
268}
269~~~~~
270
2712. Incorrect location of closing parenthesis of Handle() macro that was not detectable in OCCT 6.x will cause compiler error and must be corrected.
272
273 Example (note misplaced closing parenthesis):
274~~~~~
275aBSpline = Handle( Geom2d_BSplineCurve::DownCast(BS->Copy()) );
276~~~~~
277
278#### Use of class Standard_AncestorIterator
279
280Class Standard_AncestorIterator has been removed; use method Parent() of Standard_Type class to parse inheritance chain.
281
282#### Absence of cast to Standard_Transient*
283
284Handles in OCCT 7.0 do not have operator of conversion to Standard_Transient*, which was present in earlier versions.
285This is done to prevent possible unintended errors like this:
286
287~~~~~
288Handle(Geom_Line) aLine = ...;
289Handle(Geom_Surface) aSurf = ...;
290...
291if (aLine == aSurf) {...} // will cause compiler error in OCCT 7.0, but not OCCT 6.x
292~~~~~
293
294Places where this implicit cast has been used should be corrected manually.
295The typical situation is when Handle is passed to stream:
296
297~~~~~
298Handle(Geom_Line) aLine = ...;
299os << aLine; // in OCCT 6.9.0, resolves to operator << (void*)
300~~~~~
301
302Call method get() explicitly to output address of the Handle.
303
304@subsubsection upgrade_occt700_cdl_runtime Possible runtime problems
305
306Known situations when problems are possible at run time after upgrade to OCCT 7.0 are listed here.
307
308#### References to temporary objects
309
310In previous versions, compiler was able to detect situation when local variable of reference type to Handle is initialized by temporary object, and ensured that lifetime of that object is longer than that of the variable.
311Since OCCT 7.0, it will not work if types of the temporary object and variable are different (due to involvement of user-defined type cast), thus such temporary object will be destroyed immediately.
312
313Example:
314
315~~~~~
316// note that DownCast() returns new temporary object!
317const Handle(Geom_BoundedCurve)& aBC =
318Handle(Geom_TrimmedCurve)::DownCast(aCurve);
319aBC->Transform (T); // access violation in OCCT 7.0
320~~~~~
321
322@subsubsection upgrade_occt700_cdl_compat Preserving compatibility with OCCT 6.x
323
324If you like to preserve compatibility of your application code with OCCT versions 6.x even after upgrade to 7.0, consider the following suggestions:
325
3261. When running automatic upgrade tool, add option *-compat*.
327
3282. In order to overcome incompatibility of macro DEFINE_STANDARD_RTTI which has additional argument in OCCT 7.0, you can replace (after upgrade) its use in your code by your own version-dependent macro, which resolves to either 6.x or 7.x version.
329
330 Example:
331~~~~~
332#if OCC_VERSION_HEX < 0x070000
333 #define DEFINE_STANDARD_RTTI_COMPAT(C1,C2) DEFINE_STANDARD_RTTI(C1)
334#else
335 #define DEFINE_STANDARD_RTTI_COMPAT(C1,C2) DEFINE_STANDARD_RTTI(C1,C2)
336#endif
337~~~~~
338
339@subsubsection upgrade_occt700_cdl_wok Applications based on CDL and WOK
340
341If you have application essentially based on CDL, and need to upgrade it to OCCT 7.0, you will very likely need to convert your application code to non-CDL form.
342This is non-trivial effort; the required actions would depend strongly on the structure of the code and used features of CDL.
343
344The upgrade script and sources of specialized version of WOK used for upgrading OCCT code can be found in WOK Git repository in branch [CR0_700_2](http://git.dev.opencascade.org/gitweb/?p=occt-wok.git;a=log;h=refs/heads/CR0_700_2).
345
346[Contact us](http://www.opencascade.com/contact/) if you need more help.
347
348@subsection upgrade_occt700_bspline Separation of BSpline cache
349
350Implementation of NURBS curves and surfaces has been revised: cache of polynomial coefficients, used to accelerate calculate values of B-spline, is separated from data objects (Geom2d_BSplineCurve, Geom_BSplineCurve, Geom_BSplineSurface), into dedicated classes (BSplCLib_Cache and BSplSLib_Cache).
351
352The benefits of this change are:
353
354* Reduced memory footprint of OCCT shapes (up to 20% on some cases)
355* Possibility to evaluate the same B-Spline concurrently in parallel threads without data races and mutex locks
356
357The drawback is that direct evaluation of B-Splines using methods of curves and surfaces becomes slower, due to absence of cache. The way to avoid slow down is to use adaptor classes (Geom2dAdaptor_Curve, GeomAdaptor_Curve and GeomAdaptor_Surface): they now use cache when the curve or surface is a B-spline.
358
359OCCT algorithms are changed to use adaptors for B-spline calculations instead of direct methods of curves and surfaces.
360The same changes (use of adaptors instead of direct call to curve and surface methods) should be implemented in relevant places in applications based on OCCT in order to get maximum performance.
361
362@subsection upgrade_occt700_sorttools Removal of SortTools package
363
364Package SortTools has been removed.
365The code that used the tools provided by that package should be corrected manually.
366The recommended approach is to use sorting algorithms provided by STL.
367
368For instance:
369~~~~~
370#include <SortTools_StraightInsertionSortOfReal.hxx>
371#include <SortTools_ShellSortOfReal.hxx>
372#include <TCollection_CompareOfReal.hxx>
373...
374TCollection_Array1OfReal aValues = ...;
375...
376TCollection_CompareOfReal aCompReal;
377SortTools_StraightInsertionSortOfReal::Sort(aValues, aCompReal);
378~~~~~
379can be replaced by:
380~~~~~
381#include <algorithm>
382...
383TCollection_Array1OfReal aValues = ...;
384...
385std::stable_sort (aValues->begin(), aValues->end());
386~~~~~
387
d3839d74 388@subsection upgrade_occt700_2dlayers On-screen objects and ColorScale
27f85086 389
d3839d74 390Old mechanism for rendering Underlay and Overlay on-screen 2D objects based on Visual3d_Layer and immediate drawing model (e.g. uncached and thus slow) have been removed.
391Classes Aspect_Clayer2d, OpenGl_GraphicDriver_Layer, Visual3d_Layer, Visual3d_LayerItem, V3d_LayerMgr, V3d_LayerMgrPointer have been deleted.
27f85086 392
d3839d74 393General AIS interactive objects with transformation persistence flag Graphic3d_TMF_2d can be used as replacement of Visual3d_LayerItem.
394Anchor point specified for transformation persistence defines a corner of window (or center in case of (0, 0) point).
395To keep on-screen 2D objects on the top of main screen, them could be assigned to appropriate Z-layer.
396Predefined Z-layers Graphic3d_ZLayerId_TopOSD and Graphic3d_ZLayerId_BotOSD are intended to replace Underlay and Overlay layers within old API.
27f85086 397
d3839d74 398ColorScale object previously implemented using Visual3d_LayerItem has been moved to a new class AIS_ColorScale, with width and height specified explicitly.
399The property of V3d_View storing global ColorScale object has been removed with associated methods V3d_View::ColorScaleDisplay(), V3d_View::ColorScaleErase(), V3d_View::ColorScaleIsDisplayed(), V3d_View::ColorScale() and classes V3d_ColorScale, V3d_ColorScaleLayerItem, Aspect_ColorScale.
400Here is an example of creating ColorScale using updated API:
27f85086 401
402~~~~~
403Handle(AIS_ColorScale) aCS = new AIS_ColorScale();
404// configuring
d3839d74 405Standard_Integer aWidth, aHeight;
406aView->Window()->Size (aWidth, aHeight);
407aCS->SetSize (aWidth, aHeight);
27f85086 408aCS->SetRange (0.0, 10.0);
409aCS->SetNumberOfIntervals (10);
410// displaying
411aCS->SetZLayer (Graphic3d_ZLayerId_TopOSD);
412aCS->SetTransformPersistence (Graphic3d_TMF_2d, gp_Pnt (-1,-1,0));
413aCS->SetToUpdate();
414theContextAIS->Display (aCS);
415~~~~~
416
d3839d74 417To see how 2d objects are realized in OCCT you can call draw commands vcolorscale, vlayerline or vdrawtext (with -2d option).
418Draw command vcolorscale now requires a name of ColorScale object as an argument.
419To display this object use command vdisplay. Example:
27f85086 420
421~~~~~
422pload VISUALIZATION
423vinit
424vcolorscale cs –demo
425pload MODELING
426box b 100 100 100
427vdisplay b
428vsetdispmode 1
429vfit
430vlayerline 0 300 300 300 10
431vdrawtext t "2D-TEXT" -2d -pos 0 150 0 -color red
432~~~~~
433
434Here is a small example in c++ how to display a custom AIS object in 2d:
435~~~~~
d3839d74 436Handle(AIS_InteractiveContext) aContext = ...;
437Handle(AIS_InteractiveObject) anObj =...; // create an AIS object
438anObj->SetZLayer(Graphic3d_ZLayerId_TopOSD); // display object in overlay
439anObj->SetTransformPersistence (Graphic3d_TMF_2d, gp_Pnt (-1,-1,0)); // set 2d flag, coordinate origin is set to down-left corner
440aContext->Display (anObj); // display the object
441~~~~~
442
443@subsection upgrade_occt700_userdraw UserDraw and Visual3d
444
445#### Visual3d package
446
447Package Visual3d implementing intermediate layer between high-level V3d classes
448and low-level OpenGl classes for views and graphic structures management has been dropped.
449
450The OpenGl_View inherits from the new class Graphic3d_CView.
451Graphic3d_CView is an interface class that declares abstract methods for managing displayed structures,
452display properties and a base layer code that implements computation
453and management of HLR (or more broadly speaking view-depended) structures.
454
455In new implementation it takes place of eliminated Visual3d_View.
456As before the instance of Graphic3d_CView is still completely managed by V3d_View classes.
457It can be accessed through V3d_View interface but normally this should not be required as all its methods are completely wrapped.
458
459In more details, a concrete specialization of Graphic3d_CView is created and returned by graphical driver on request.
460Right after creation the views is directly used for setting rendering properties and adding graphical structures to be displayed.
461
462The rendering of graphics is possible after mapping a window and activating the view.
463The direct setting of properties makes obsolete usage of intermediate structures with display parameter
464like Visual3d_ContextView and etc (the whole package of Visual3d become redundant).
465
466New location of functionality previously provided by Visual3d package:
467- Logic of managing display of structures was put from Visual3d_ViewManager into Graphic3d_StructureManager.
468- Removed Visual3d_View class. Logic of managing computed structures was put into base layer of Graphi3d_CView.
469- Removed all intermediate structures for storing view parameters e.g. Visual3d_ContextView.
470 All settings are kept by instances of Graphic3d_CView
471- Removed Visual3d_Light intermediate class.
472 All light properties are still stored in Graphic3d_CLight structure.
473 The structure is directly access by instance of V3d_Light classes.
474- Moved all needed enumerations into Graphic3d package.
475
476#### Custom OpenGL rendering and UserDraw
477
478Old APIs based on global callback functions for creating UserDraw objects and for performing custom OpenGL rendering within the view have been dropped.
479UserDraw callbacks no more required since OpenGl_Group now inherits Graphic3d_Group and thus can be accessed directly from AIS_InteractiveObject:
480
481~~~~~
482//! Class implementing custom OpenGL element.
483class UserDrawElement : public OpenGl_Element {};
484
485//! Implementation of virtual method AIS_InteractiveObject::Compute().
486void UserDrawObject::Compute (const Handle(PrsMgr_PresentationManager3d)& thePrsMgr,
487 const Handle(Prs3d_Presentation)& thePrs,
488 const Standard_Integer theMode)
489{
490 Graphic3d_Vec4 aBndMin (myCoords[0], myCoords[1], myCoords[2], 1.0f);
491 Graphic3d_Vec4 aBndMax (myCoords[3], myCoords[4], myCoords[5], 1.0f);
492
493 // casting to OpenGl_Group should be always true as far as application uses OpenGl_GraphicDriver for rendering
494 Handle(OpenGl_Group) aGroup = Handle(OpenGl_Group)::DownCast (thePrs->NewGroup());
495 aGroup->SetMinMaxValues (aBndMin.x(), aBndMin.y(), aBndMin.z(),
496 aBndMax.x(), aBndMax.y(), aBndMax.z());
497 UserDrawElement* anElem = new UserDrawElement (this);
498 aGroup->AddElement(anElem);
499
500 // invalidate bounding box of the scene
501 thePrsMgr->StructureManager()->Update (thePrsMgr->StructureManager()->UpdateMode());
502}
27f85086 503~~~~~
d3839d74 504
505For performing custom OpenGL code within view, user should inherit from class OpenGl_View.
506See the following code sample:
507
508~~~~~
509//! Custom view.
510class UserView : public OpenGl_View
511{
512public:
513 //! Override rendering into the view.
514 virtual void render (Graphic3d_Camera::Projection theProjection,
515 OpenGl_FrameBuffer* theReadDrawFbo,
516 const Standard_Boolean theToDrawImmediate)
517 {
518 OpenGl_View::render (theProjection, theReadDrawFbo, theToDrawImmediate);
519 if (theToDrawImmediate)
520 {
521 return;
522 }
523
524 // perform custom drawing
525 const Handle(OpenGl_Context)& aCtx = myWorkspace->GetGlContext();
526 GLfloat aVerts[3] = { 0.0f, 0,0f, 0,0f };
527 aCtx->core20->glEnableClientState(GL_VERTEX_ARRAY);
528 aCtx->core20->glVertexPointer(3, GL_FLOAT, 0, aVerts);
529 aCtx->core20->glDrawArrays(GL_POINTS, 0, 1);
530 aCtx->core20->glDisableClientState(GL_VERTEX_ARRAY);
531 }
532
533};
534
535//! Custom driver for creating UserView.
536class UserDriver : public OpenGl_GraphicDriver
537{
538public:
539 //! Create instance of own view.
540 virtual Handle(Graphic3d_CView) CreateView (const Handle(Graphic3d_StructureManager)& theMgr) Standard_OVERRIDE
541 {
542 Handle(UserView) aView = new UserView (theMgr, this, myCaps, myDeviceLostFlag, &myStateCounter);
543 myMapOfView.Add (aView);
544 for (TColStd_SequenceOfInteger::Iterator aLayerIt (myLayerSeq); aLayerIt.More(); aLayerIt.Next())
545 {
546 const Graphic3d_ZLayerId aLayerID = aLayerIt.Value();
547 const Graphic3d_ZLayerSettings& aSettings = myMapOfZLayerSettings.Find (aLayerID);
548 aView->AddZLayer (aLayerID);
549 aView->SetZLayerSettings (aLayerID, aSettings);
550 }
551 return aView;
552 }
553};
554
555~~~~~
556
557@subsection upgrade_occt700_localcontext Deprecation of Local Context
558
559Conception of Local Context has been deprecated.
560Related classes (AIS_LocalContext) and methods (AIS_InteractiveContext::OpenLocalContext() and others) will be removed within some future OCCT release.
561
562The main functionality provided by Local Context - selection of object subparts - can be now used within Neutral Point without opening any Local Context.