vsg-dev/VulkanSceneGraph

Calling viewer->update() immediately after viewer::create() crashes

Closed this issue · 3 comments

dov commented

Describe the bug
viewer::update() references _frameStamp() which is not initialized in the constructor. Thus calling viewer->update() immediately after Viewer::create() causes program to crash.

To Reproduce

Compile and run the following code:

auto viewer = vsg::Viewer::create();
viewer->update();

Expected behavior
No crash

Desktop (please complete the following information):

  • OS: Linux
  • Version: commit:8a229b30637eea6fcfd9ace3d0745415dd563d7a

Additional context

The problem is worked around (_frameStamp() is initialized) if the function viewer->advanceToNextFrame() is called immediately after vsg::Viewer::create().

Also note that I only tested this with vsgQt:Viewer but since the uninitialized variable access is in VulkanSceneGraph Viewer.cpp , I believe the problem occurs everywhere.

Another question you may ask is why I need to call update() so early. The reason is that it was called indirectly during the Qt initialization, because I had bound a function (which is also used elsewhere) to a Qt event, which when triggered called the update() function.

robertosfield commented

I'm currently thinking that initializing FrameStamp in the Viewer constructor would be the way to avoid this issue. I will review the code today.

robertosfield commented

I have moved the _frameStamp initialization into the Viewer constructor with commit:7a4950f672cc6640cb08f55fbd1b260da6b816a6 which is now part of VSG master. Could you please test. Thanks.

dov commented

Thanks. This fixes the crash.

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