How to make emissive catch shadows?

[andreasng]

Godot Version

4.2.1

Question

I have this issue where i want to have back facing on grass to be emissive (because it just looks better when a cluster of grass hasn’t really got dark sides)

So to combat that i’ve done this:

vec2 base_uv = UV;
vec4 albedo_tex_ = texture(albedo_tex,base_uv);

	if (FRONT_FACING)
	{
		ALBEDO = albedo.rgb * albedo_tex_.rgb;
	}
	else
	{
		EMISSION = albedo.rgb * 0.75 * (1.0 - UV.y);
	}

It looks pretty good…

But not when there is shadow on the grass from other objects →

(see here! only the front faces recieve the shadows, but not the backfaces. )

So I’m wondering if i can know if there is shadow being cast on the backfaces, or if there is any other great way of doing this!?

[cajgamer07]

is it possible to get the colour from the front faces, and use that? I wouldn’t know because i haven’t done this stuff yet

[andreasng]

I think it isn’t possible in the color stage because color and light is two different render stages. So trickery is needed for sure. Hope someone knows.

[andreasng]

I’m wondering if anyone knows if anything can be done in the void light stage?
Trying things out but so far no good results.

[andreasng]

I guess this is impossible…

[andreasng]

OK!!! I tried stuff out and got this to actually kind of do the thing!!!

	if (FRONT_FACING)
	{
		ALBEDO = albedo.rgb * albedo_tex_.rgb;
	}
	else
	{
		//EMISSION = albedo.rgb * 0.75 * (1.0 - UV.y) * lightMultiplier;
		//This looks great - But cant use emission(DUHH)!
		//This however does the job!
		BACKLIGHT = albedo.rgb * 10.0;//YAY
		ALBEDO = albedo.rgb * (1.0 - UV.y);
	}

[gertkeno]

Will you be posting the completed shader online anywhere, like godotshaders.com?

[andreasng]

I could. Yeah​:star_struck:. I’m just a bit affraid of people calling me out as a bad programmer… Which is absolutely true.
There would be 1000s of ways to make it ALOT better!

[gertkeno]

Well, I like it!