[SOLVED] Using a vtk renderer in QtQuick

[z.emb]

Its not working without the push and pop (nothing is rendered, only the background). Unfortunatelly I cannot tell you why, I'm no OpenGL expert.

[Martell Malone]

I think I understand why.
The only problem is GLES doest support those functions so how do we get around them?

Maybe I should make a new thread to this issue?

[Martell Malone]

I found a new way of solving this problem.

It Involves setting up a separate opengl context and switching between the two before and after binding and releasing the fbo.

Any idea how to draw correctly for a y inverted fbo.
On qquickpainteditem we can set it to flip but not for the qsgtexture :/

[z.emb]

Hey, thanks for your reply. Can you provide some code how you do that?
In my case, it also seems to be the cleanest way to do the same thing and I wan't to try that. :-)

For the flipping problem I would naivly just scale (glScale) the y-Axis with -1. But as I mentioned, I'm no OpenGL expert.

[Martell Malone]

Hey z.emb

I used what was on this thread.

http://qt-project.org/forums/viewthread/25268/

I just changed this line for the flip y.

QSGGeometry::updateTexturedRectGeometry(&m_geometry,
QRectF(0, 0, m_size.width(), m_size.height()),
QRectF(0, 0, 1, 1));

to

QSGGeometry::updateTexturedRectGeometry(&m_geometry,
QRectF(0, 0, m_size.width(), m_size.height()),
QRectF(0, 1, 1, -1));//0011 = old y fliped

[z.emb]

Can you give me some code how you switched the GL-context?

[Martell Malone]

Hey Guys,

Apologies about not replying.
I didn't realize I got a response.

I swapped the context at the very beginning by using the code in this thread

http://qt-project.org/forums/viewthread/25268/

Hope that helps Ricky, just got your pm.

Many Thanks
Martell

[rlonka]

Hi,

I still did not get it.
Could you, please, anyone post a full example about rendering vtk to qtquick?
I was trying to understand the discussion but I did not get through...

Best regards,

radek

[rpetryniak]

Hey, I join to this request. Even the simplest example would be helpful.

Regards,
rafal

[niker91]

I have created a repository with code that integrates VTK with Qt QuickControls 2, tested with VTK 8 and Qt 5.9. You can find the code here https://github.com/nicanor-romero/QtVtk with building instructions in the README. Also a brief article about it,
https://blog.bq.com/es/integrating-qtquickcontrols-2-with-vtk/