Message boxes (rendered as vectorized OpenGL graphs)

The namespace mrpt::opengl::gl_utils contains the function renderMessageBox() for drawing message boxes into OpenGL rendering contexts.

This method is highly configurable, and may include transparencies, single or multi-lined text and automatic scaling of the provided text fonts if needed, such as the text does not get out of the box.

For more details, refer to the example: $MRPT/samples/display3D_custom_render