Raindrop effect in CesiumJS

Hellow, I just realized raineffect in cesiumJS, with control of direction raindrop and a water surface polygon which have effects of rainripple mixed of reflection&refraction. I’d like to share the result and process with everyone here, hope to be helpful to you, and happy to see any advice about the effects. screenshots are like below:

change imageprovider will not influence the effect:

it is realized by CesiumJS postprocessstage, before this, only I can do is fullview render post,the problem is no matter what direction of camera, the rain drop is in uniform direction, but I want the raindrop drop much more like real raindrop which direction is changed with the camera change, so this time eventually realize it with sdf raymarch in postprocessstage. Now with camera changed, the rain drop direction changed too:

Another effect is water surface,including rainripple, reflection, refration, about rainripple, mainly shamely refer to shadertoy Rainier mood (shadertoy.com), what leave me to do is coordinate transform, otherwise it will be the same ripple no matter how camera changed. As to refration and reflection, what I do is offscreen render and texture coordinate compute.