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Yet Another V3d_View Bug: Black Screen Once Again.

fhchina's picture

Hi, everybody:

You can easily reproduce the following bug in any MFC Samples:

New two empty documents, make one of them maximizied, then close one child window.

OK, you can see the other child window is black screen.

From the servey of, most of us are using OCC as industrial development, but any of us could allow this bug in a serious application?


Stephane Routelous's picture

Are you using W95 or W98 ?
What is your graphic card ?

fhchina's picture

Hi, Stephane:

I am using Windows 2000 Professional. My graphic card is very simple(or poor, :-)):
Intel(r) 82815 Graphics Controller.

I am very strange if this problem only occurs on my box?
Couldn't you reproduce this bug?

But OpenGL should be system independent. It seems impossible to be hardware related, I guess.


Stephane Routelous's picture


I know that this problem often appears with OpenCASCADE on Windows9x.

As you said, OpenGL ( the programming "language" ) is system independant. But the drivers are NOT.
If the driver is bugged, you will have bug in your OpenGL application.

In your case, it seems that you cannot have 2 OpenGL "devices" on the screen at the same time.
If you know OpenGL, it could be a problem with the wglMakeCurrent function.

Try to download the newest drivers for your graphic card, or buy a decent one ;-)


fhchina's picture

Thank you, Stephane.

I will try, anyway. Or driver, or OpenGL, or other machine.

Stephane Routelous's picture

No problemo !

fhchina's picture

Hi, Stephane:

I want to say: couldn't access once agin. :-).

By IE, it is impossible. Then I nslookup its IP, I find But using this IP I will get It may be a problem with GANDI, I think.


Mikael Aronsson's picture

Hi !

The URL works fine for me. no problems at all.


Mikael Aronsson's picture

Hi again !

You might have a DNS problem somewhere, when I ran nslookup on it I got


Philippe Carret's picture

You should change the graphics resolution to 1024 x768 and number of colours to 16 bits or 256 colours. Try any combination. Shut down you software before any change.
Sometimes OCC works fine when these changes are done.
The last driver is MANDATORY too !
A real OpenGL card is better

Some CAD company (Solidworks for ex.) display info about Graphic Card test.
I personnaly like NVIDIA GE-FORCE 2 or 4

Windows98 is very hard for OCC developpers.

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