Water example viewport goes black momentarily on resize

[crispweed]

Looking at the resize function for this example, I see:

        if sc_desc.width == 0 && sc_desc.height == 0 {
            // Stop rendering altogether.
            self.active = None;
            return;
        } else {
            // The next frame queued is the wrong size: (0, 0),
            // so we skip a frame to avoid crashes where our
            // textures are the correct (window) size, and the
            // frame is still (0, 0).
            self.active = Some(self.current_frame + 1);
        }

That doesn't seem to make sense, and changing to the following resolves the issue for me (viewport no longer goes black momentarily on resize):

       if sc_desc.width == 0 && sc_desc.height == 0 {
            // Stop rendering altogether.
            self.active = None;
            return;
        } 

        self.active = Some(self.current_frame);

[kvark]

Sounds reasonable. Want to make a small PR?