I understand that for any of the Qt OpenGL convenience classes to correctly be initialized and used, they must be called with a valid current context. So, I designed my classes to be initialized from my overloaded QOpenGLWidget::initializeGL() function, in which the documentation states the context is created and made current (albeit without a framebuffer).
However, when initializeGL() attempts to initialize one of my subclasses MeshObject, specifically calling the function QOpenGLVertexArrayObject::create(), the program crashes with the message
Read access violation at 0x0
Going through with a debugger, note the call stack:
There are calls being made to QPainter::drawImage, which would surely fail as there is no framebuffer present.
But why is there a QPainter::drawImage call happening when I try to create a vertexArrayObject? Surely this function should have no involvement with painting to the screen.
ALthough the documentation also states that QOpenGLVertexArrayObjects will only work on some OpenGL ES 2.0 platforms, vbuffer.create() causes exactly the same scenario to occur, and I've already used QOpenGLVertexArrayObjects on this exact machine on a previous project with absolutely no problems.
Complete stack trace:
0 QPainter::drawImage Qt5Guid 0x58292a56
1 QPainter::drawImage Qt5Guid 0x5829203c
2 MeshState::initBuffers meshobject.cpp 71 0x2fb793
3 SceneObject::setupObjects sceneobject.cpp 18 0x2fa1eb
4 SceneObject::initialize sceneobject.cpp 12 0x2fa12f
5 OpenGLWidget::initializeGL openglwidget.cpp 34 0x2f8ecf
6 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x587a9859
7 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x587a86da
8 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x58770104
9 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x587a8850
10 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5872548e
11 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x587235f5
12 QSortFilterProxyModel::mapToSource Qt5Cored 0x591b6b47
13 QSortFilterProxyModel::mapToSource Qt5Cored 0x591bf379
14 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5877a3a3
15 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5877a618
16 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5876be41
17 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5876c0bb
18 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x58779441
19 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5877a62e
20 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5876be41
21 QAbstractScrollArea::setHorizontalScrollBar Qt5Widgetsd 0x5876c0bb
22 main main.cpp 10 0x2f3419
23 WinMain qtmain_win.cpp 113 0x2fdcdd
24 __tmainCRTStartup crtexe.c 618 0x2fd0bf
25 WinMainCRTStartup crtexe.c 466 0x2fce7d
26 BaseThreadInitThunk KERNEL32 0x772e38f4
27 __RtlUserThreadStart ntdll 0x77865de3
28 _RtlUserThreadStart ntdll 0x77865dae
