Update a part of the texture from the contents of a window.
*
No additional check is performed on the size of the window, passing an
invalid combination of window size and offset will lead to an undefined
behaviour.
*
This function does nothing if either the texture or the window was not
previously created.
*
Update a part of the texture from the contents of a window. * No additional check is performed on the size of the window, passing an invalid combination of window size and offset will lead to an undefined behaviour. * This function does nothing if either the texture or the window was not previously created. *