Why QGLFramebufferObject in QGraphicsItem donâ€™t work?

**Student3000** · 23rd September 2010, 21:12

good news, iâ€™ve found a way to rendering a correct fbo to the quad in the scene.

it was dependend of the order of the painter->beginNativePainting(); line. i switch the order, that the painter->beginNativePainting(); is before the QGLContext and QGLFramebufferobject is init.

the message is still active but the result is correct.

source

Qt Code:

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painter->beginNativePainting();
 
	// ------------ FBO begin ------------
 
		context = new QGLContext(QGLFormat(QGL::SampleBuffers | QGL::DoubleBuffer | QGL::AlphaChannel), widget);
		context->create(); // !!!
		context->makeCurrent();
 
		fbo = new QGLFramebufferObject(512, 512); // GLWidget::GLWidget (constructor)
 
		fbo->bind();
		{
			...
		}
		fbo->release();

painter->beginNativePainting();
	
	// ------------ FBO begin ------------

		context = new QGLContext(QGLFormat(QGL::SampleBuffers | QGL::DoubleBuffer | QGL::AlphaChannel), widget);
		context->create(); // !!!
		context->makeCurrent();

		fbo = new QGLFramebufferObject(512, 512); // GLWidget::GLWidget (constructor)

		fbo->bind();
		{
			...
		}
		fbo->release();

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