QGLContext::bindTexture changes the current GL context; can't change it back

[Brady Brenot]

I'm trying to get Stellarium working with necessitas, but I've hit an odd thing. After QGLContext::bindTexture returns, once finds that the current context (found from QGLContext::currentContext()) has changed. Attempting to change it back (QGLContext::makeCurrent()) has no effect, the old context is still valid (QGLContext::isValid()), and the QGLWidget's context is still the old one. I've also checked to see if the two contexts are sharing (QGLContext::areSharing), but that's a negative.

I can take out the assert checking if the context matches what we expect and the program works. No crashes, no weirdness (that I've noticed so far). Is this safe?

From  http://bazaar.launchpad.net/~brady.brenot/stellarium/android-port/view/head:/src/core/StelPainter.cpp :

690	if (isNoPowerOfTwoAllowed)
691	strImage = QPixmap(newTex->subTexWidth, newTex->subTexHeight);
692	else
693	strImage = QPixmap(StelUtils::getBiggerPowerOfTwo(newTex->subTexWidth), StelUtils::getBiggerPowerOfTwo(newTex->subTexHeight));
694	newTex->width = strImage.width();
695	newTex->height = strImage.height();
696
697	strImage.fill(Qt::transparent);
698
699	QPainter painter(&strImage);
700	painter.setFont(qPainter->font());
701	painter.setRenderHints(QPainter::TextAntialiasing, true);
702	painter.setPen(Qt::white);
703	painter.drawText(-strRect.x(), -strRect.y(), str);
704
705	// Create and bind texture, and add it to the list of cached textures
706	newTex->texture = StelPainter::glContext->bindTexture(strImage, GL_TEXTURE_2D, GL_RGBA, QGLContext::NoBindOption);
707

[faenil]

could you create two context in Qt for Android?

check if the second context gets created, because create() always returns false to me...

I have tried creating a QGLContext and a QGLPixelBuffer, and both fail

[Brady Brenot]

I know there's a post mentioning that only one QGLWidget is supported. I'm not intentionally trying to create a second context, we only need one.

I've got a feeling that it's just returning an erroneous current context. If I just ignore it and keep on sending GL commands, and specifically using the old context when required (e.g. for QGLContext::bind), everything still works. So this doesn't seem to be blocking me in any way, it's just odd and doesn't conform to what the other platforms do.

[Brady Brenot]

I forgot to mention: when that function is going, necessitas prints

setFullScreen false

setFullScreen false