@GrecKo , @SGaist , @mnesarco - Has the OP's issue with QQuickFrameBufferObject (nothing rendered) been resolved in Qt 6? I've migrated to 6.7.2 and my QQuickFrameBufferObject-based application now segfaults somewhere in the Qt libraries. I realize that QQuickFrameBufferObject is now considered a 'legacy' class and works only with OpenGL, but if possible I'd like to track down the segfault and move on, deferring use of RHI to another day.
Thanks!

I did in fact have to call glDrawBuffers myself. I assumed this was handled by the FBO binding, but apparently not.

QOpenGLExtraFunctions* f = QOpenGLContext::currentContext()->extraFunctions(); GLenum bufs[2] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 }; f->glDrawBuffers(2, bufs);

This seems strange to me that the FBO abstraction supports color attachments, but requires extra functions to use them.