Draw renderers into render texture with sorted 2d sprite mask

[eclipse130300]

Hello, dear unity forum!
I have a pretty hard to solve issue - I can’t get around with rendering my custom mask into render texture with respect of scene geometry (sprites)
I would like to make a 2d water shader using hand-drawn heightmaps - I put them into the scene, set sorting layer to “water” , set appropriate order in layer,then animate verticies with shader, hide rendering from the renderer asset and draw them through scriptable renderer feature with method

context.DrawRenderers(renderingData.cullResults, ref drawingSettings, ref _filteringSettings, ref _renderStateBlock);

It gives me a really nice heightmap to sample for post-processing water

Unfortunately, it did not take into account another scene sprites. At the very least, after applying post processing I get this overlapping issue

So…if I render everything as is - without hiding “water” layer - the result is perfect. I would like to keep only the pixels occupied by heightmap shader after the whole scene is rendered. Is there a good approach for this?

[eclipse130300]

For anyone interested in future… I could not get better solution then create custom rendering order through c# scripting…
So the idea is that -

1. Setup 2 cameras. Set culling mask for for one of them - everything except water layer, another should draw everything.
2. Use custom c# scripting solution. You have to collect all renderers in the scene and sort them BY YOUR OWN

allRenderers.OrderByDescending(x => x.transform.position.z).ThenBy(x => x.sortingOrder);

ofc, you need to include sorting layer here if you want to draw like unity does.

Actually, here I do my own sorting, but refer to this page if you want to have exact replica

Unity - Manual: 2D Sorting

3. In renderer feature use the resulting collection with commandBuffer.DrawRenderers().
   before that, I check if renderer I want to draw is inside layer “water” - so I draw it with assigned shader, otherwise (in any other renderer except water), I draw with shader that outputs just black color (0,0,0,0)

This solution works with 2D painter drawing algorithm. For 3D you can check something better, for example

How to Mask Custom Renderer Features correctly?

Hello, Turns out I solved this issue some days after I got it first time and made since then a GitHub repo with the solution I now use every time I want to mask one of these screen-space effects.

[eclipse130300]