Flutter integration with Qt

[slandino]

Hi, I have an existing application on C++ with Qt and I wanna extend it by using Flutter. I have tried to use https://github.com/flutter/engine/tree/main/shell/platform/embedder. Currently I am trying to configure engine via FlutterRendererConfig but looks like I should use low level rendering primitives like QOpenGLContext. I have faced an issue with it, because QOpenGLContext cannot be used outside of the thread where it was created. But I need to use it for configuring Flutter engine (code snippet below).

FlutterRendererConfig config = {};
     config.type = kOpenGL;
     config.open_gl.struct_size = sizeof(config.open_gl);
     config.open_gl.make_current = [](void *userdata) -> bool {
         QOpenGLContext *context = static_cast<QOpenGLContext *>(userdata);
         return context->makeCurrent(static_cast<QWindow *>(context->surface()));
     };
     config.open_gl.clear_current = [](void *) -> bool {
         QOpenGLContext::currentContext()->doneCurrent();
         return true;
     };
     config.open_gl.present = [](void *userdata) -> bool {
         QOpenGLContext *context = static_cast<QOpenGLContext *>(userdata);
         context->swapBuffers(static_cast<QWindow *>(context->surface()));
         return true;
     };

Maybe somebody have done this before and could share a small code snippet with correct configuration? Or there are some ideas how to fix QOpenGLContext limitation?

[Alessandro M]

Hi Slandino, I started working a few days ago on a project to mix Qt and flutter. I have already some working code, but it's using offscreen buffers (my final objective is to make a plugin to have a flutter layer in OBS) so I've not even looked on how to render to a window context. But the code may still work for you. I've commited the mess of code I wrote so far to https://github.com/hefsoftware/temp_qt_flutter (it compiles on windows, at least for me). Hope it will give you some help.