In some cases (e.g. when loading resources with XMLHttpRequest) we may end up executing OpenGL calls outside of the initGL and renderGL signals that make the QtCanvas3D OpenGL context active. Initial fix was to remove the "doneCurrent" call at the end of renderGL signal handling. But a proper solution would be to define an extension API to QtCanvas3D that includes "makeCurrent" that can be called in these cases from JavaScript to ensure the context indeed is current before making OpenGL API calls.

This is needed if customer uses e.g. QtDataVisualization QML component together with QtCanvas3D on Android, in that case we can end up executing OpenGL calls with wrong non-shared OpenGL context active.