Open CASCADE, the 3D modelling kernel
3D modeling & numerical simulation

Search the Forums
See All Topics
Open CASCADEShowroomGet it!Developer CornerSupport and ProductsAbout us
Technical overview
Areas of use
Advantages
FAQ
Screenshots
Shape factory
Shape gallery
Demonstrations
What's new
System requirements
Download Center
Public license
Documentation
Getting started
Forums
Open Source community
Training and e-learning
A-la Carte Support
Value-added software
Complementary Components
Customer Corner
Company Profile
Marketing Materials
Contact Us
News
Home / Developer Corner / Forums / Usage issues / Memory bug during graphics initialization (OCC6.5.3) ?

Memory bug during graphics initialization (OCC6.5.3) ?

Memory bug during graphics initialization (OCC6.5.3) ?
Mark Blome 2012/09/01 15:56
Hi everybody,

I'm having an issue during graphics display initialization
in OCC 6.5.3 on Linux and Mac OS X that was not present in OCC 6.5.0.
For the GUI I develop (through PythonOCC) I repeatedly create (and subsequently destroy)
graphics displays using something like:
short hi = static_cast<short>(window_handle >> 16);
short lo = static_cast<short>(window_handle);
gd = new Graphic3d_GraphicDevice(std::getenv("DISPLAY"));
myWindow =new Xw_Window(gd,static_cast<Standard_Integer>(hi),static_cast<Standard_Integer>(lo),Xw_WQ_3DQUALITY);
myV3dViewer = new V3d_Viewer( gd , (short* const)"viewer" );
myV3dViewer->Init();
and so on

This typically works the first few times after program start without any issues,
but then fails (unpredictably) at line
     gd = new Graphic3d_GraphicDevice(std::getenv("DISPLAY"));
with error messages like
     _X11TransOpen: Unable to find transport for <an invalid DISPLAY variable>
that are caused by the (initially correct) DISPLAY variable being scrambled by what
seems to me a memory bug in OSD_Environment.cxx (presumably in function Build())

From the line above I traced this issue down to
1) Graphic3d_GraphicDevice.cxx: In constructor at line 75
     status = MyGraphicDriver->Begin (connexion);
2) OpenGl_GraphicDriver_1.cxx: In Begin at line 38
     openglDisplay = new OpenGl_Display(ADisplay);
3) OpenGl_Display.cxx: In constructor at lines 75-76
OSD_Environment aDispEnv ("DISPLAY", theDisplay);
aDispEnv.Build();

After destruction of "aDispEnv" the content of "theDisplay" is scrambled,
which subsequently leads to the graphic initialization to fail (in Graphic3d_GraphicDevice constructor, "connexion" is scrambled as well).
I assume there is something going wrong in OSD_Environment::Build() function. If I uncomment the
two lines in OpenGl_Display.cxx the issue disappears on Linux and Mac OS X (the DISPLAY environment variable is present anyway). Am I doing something wrong here ?

Thanks for any help on this,
Mark

 
 
Latest news
  • Open CASCADE Technology 6.7.0 is available for download!
  • Open CASCADE Technology 6.6.0 is available for download!
  • Open CASCADE Technology 6.5.5 is available for download!

  • © OPEN CASCADE 2000 - 2014  |  Search  |  Contacts   |  Site map