Pretty cool, are those sudo cloud reflections as well?
Nice catch! Yes, they are. SSR can reflect anything in the scene, including the aircraft (I'll try to get a screenshot showing that later).
Nice (though I maintain that you'd see such reflections only in rare occasions when the water is really calm and then usually in lakes...)!
That's why SSR is the perfect use-case for water reflections. SSR stops reflecting things when they are out of the screen. In the case of water, things other than the water itself start going out the screen when the view angle is high, which matches real life behavior due to fresnel.
What's the performance footprint - do you render it (well, the fragment part probably) essentially twice, or is it cheaper than that?
SSR is basically raytracing, but with a very low iteration count and in a fullscreen quad to maintain interactive framerates. Performance is therefore only dependent on screen resolution, not scene complexity (a good thing since FG is usually CPU bound). In a good implementation (not mine
) you could run this pass alone in around 2.5ms in <5 year old hardware, which is
much faster than say planar reflections, which require rendering the whole scene twice. Another advantage is that SSR works on basically anything without a performance impact, as long as you supply its normals and some color, so for example you can get real time reflections of the aircraft on a wet runway. I just showed water because it's the most "visible" use-case for SSR.