Helping to Make an Awesome Lighting Shader...

Hey guys! Sup?
I'm Oliver and it's my first post here (Why newbies always says that?? xD )
Anyway...

I'm dealing with a concept to use best rendering apps out there to light our unity scene up and I need your help and experiences to make it happen.
Stay on line ...

Background
I'm dealing with this concept for 3-4 years , Back in unity 4 I had shadow masking idea since I saw the method was used in Remember Me video game.
I asked on some places and people answered it's not possible on unity and well , Unity added shadow masking in unity 5.

In remember me which made by Unreal Engine 3 , they baked every light static shadows in a separate texture and they used it to blend dynamic shadows with static shadows without any overlapping , which explains how a game like Remember Me had a amazing graphic in its time.


Unity Shadow Mask
After I found out unity added shadow masking I felt so happy and good about it but it didn't take long.
Limitation of 4 light because of 4 channel (RGBA) and mixing GI Bounces through dynamic lighting ?
What if we can bake everything in scene via a amazing render engine with high accuracy like (V-Ray) and just use dynamic lights on dynamic objects and mix their shadows on static objects ?



Per-Light Shadow Mask Method
Okay here we go , it's pretty simple!
If there was a way to get shadows from specific and pre-defined lights on shader and use it as a mask , it could solve all problems with this concept

Here's a simple scene with 6 baked maps from V-Ray :



Channels [Baked Maps] :

• Light A Direct
  
• Light B Direct
• Light A Indirect
• Light B Indirect
• Light A Shadowmask
• Light B Shadowmask

Okay , now if we have two more surface shader channel as ...

• Light A Shadow Channel On Surface Shader
• Light B Shadow Channel On Surface Shader

We could use this processing to build Light A and Light B beauty channels :

A ) Multiply Dynamic Shadow Map A on Direct Light A then Add Indirect A and Here is Result :



B ) Multiply Dynamic Shadow Map B on Direct Light B then Add Indirect B and Here is Result :



C ) In final step , We just use Screen Blend on all light layers to mix them together :



And here we go, Final Result :

About this footage :
Made by 3dsmax and aftereffects with same channels and methods explained above.
Whole scene and shadows are baked only exploded sphere and its shadows are dynamic.

I know unity shadow system is fully customizable using 'UnityShadowLibrary.cginc' and I know unity
uses HLSL so this link can be helpful ( Tutorial 41: Multiple Light Shadow Mapping )

I don't know much about shader writing , can you guys tell me is this possible and if yes help me to make it happen ? I know unity lighting system is pretty good enough right now but guess what you can do with power of a renderer like V-Ray...


Is it possible to get shadow map of specific lights in shader as a texture 2D or anything to mask emission ?

Here's a starter-kit for people like challenges :
Download Unity 2019 ShadowBlend Starter-Kit [ Tiny Upload ]
Download Unity 2019 ShadowBlend Starter-Kit [ Unity Server ]

I already did a masking with Light Attenuation but it sucks ( Fact : I Suck ) :[

ShadowBlend Vs Light Attenuation :



Any help would be appreciated! Thank you ^^