QOpenGLContext memory leak

Megamouse

Hi everyone,

I've got this problem where deleting my OpenGLContext does not work. The VRAM increases with every new creation of MyWindow. The context is created in another Thread with following code.

if (void* context = MakeContext())
{
	return std::shared_ptr<void>(context, [this](void* cxt) { DeleteContext(cxt); });
}

void* MyWindow::MakeContext()
{
	auto context = new QOpenGLContext();
	context->setFormat(m_format);
	context->create();
	return context;
}

void MyWindow::DeleteContext(void* context)
{
	((QOpenGLContext*)context)->deleteLater();
}

Using following method results in a random crash on new Creation of MyWindow after the first time.
Yet it fixes the VRAM issue.

void MyWindow::DeleteContext(void* context)
{
	delete (QOpenGLContext*)context;
}

What am I doing wrong?

Edit:
I noticed it crashes on new context creation.

void* MyWindow::MakeContext()
{
	auto context = new QOpenGLContext();
	context->setFormat(m_format);
	context->create(); // this line crashes
	return context;
}

Megamouse

Somehow this seems to have fixed it to some extend. But I have no clue why and if it is the best solution.

void MyWindow::DeleteContext(void* context)
{
	QOpenGLContext* trash = ((QOpenGLContext*)context);
	trash->deleteLater();
	trash->~QOpenGLContext();
}

SGaist

Hi,

You should use qobject_cast rather that C style cast. Then calling the destructor is usually not something you do. You should simply replace deleteLater for delete if you want to delete everything immediately.

Megamouse

It would not have made a difference. It was a bug in the AMD driver. Our expert used native routines and it still crashed

SGaist

Thanks for the feedback !