Anyway to include GI information or send out GI information using custom shader?

wonder what is the exact code to be used in shader to allow GI information been passed when set this object to lightmap static... for example I want to able to write my own custom water shader, by marking the water static, I want my water able to affect my surrounding areas...

 

Anybody?
1. Include this sub shader to any other shader I write I assume it is passing meta information to unity regarding for GI and light mapping?
// ------------------------------------------------------------------
//Extractsinformationforlightmapping, GI (emission, albedo, ...)
//Thispassitnotusedduringregularrendering.
Pass
{
Name"META"
Tags { "LightMode"="Meta" }

CullOff

CGPROGRAM
#pragmavertexvert_meta
#pragmafragmentfrag_meta

#pragmashader_feature_EMISSION
#pragmashader_feature_METALLICGLOSSMAP
#pragmashader_feature____DETAIL_MULX2

#include "UnityStandardMeta.cginc"
ENDCG
}


2. This assuming below is using realtime GI for different shaders?
I looked into the standard shader code, I see that Unity has this:
UnityGIgi = FragmentGI (
s.posWorld, occlusion, i.ambientOrLightmapUV, atten, s.oneMinusRoughness, s.normalWorld, s.eyeVec, dummyLight);
half3color = UNITY_BRDF_PBS (s.diffColor, s.specColor, s.oneMinusReflectivity, s.oneMinusRoughness, s.normalWorld, -s.eyeVec, gi.light, gi.indirect).rgb;
color += UNITY_BRDF_GI (s.diffColor, s.specColor, s.oneMinusReflectivity, s.oneMinusRoughness, s.normalWorld, -s.eyeVec, occlusion, go);

To calculate the PBS and GI into color, assuming that I don't want Physical based shading, I can then just not use the UNITY_BRDF_PBS function?

3. Any documentation on this?

#if (SHADER_TARGET < 30)
outDiffuse = 1;
outSpecSmoothness = 1;
outNormal = 0;
outEmission = 0;
return;
#endif

4. also about this... so shader target using opengles 2.0 will not have any dynamic emission?

 

I'm having a hard time finding a proper solution for this, too.
Some documentation or examples with a practical use case would be great.