Surface Shader: Achieve pure black

Questions & Answers
1

I am trying to create a lit shader, that behaves just like always, but - under some conditions - is pure black.
I created a surface shader and adapted the surf function:

if (condition < 0.5) {
    o.Albedo = 0;
    o.Metallic = 0;
    o.Smoothness = 0;
    o.Alpha = 1;
} else {
    o.Albedo = c.rgb;
    o.Metallic = _Metallic;
    o.Smoothness = _Glossiness;
    o.Alpha = c.a;
}

The result looks like this:

109870-shader.png
109870-shader.png1323×633 150 KB

As you can see, it kind of works, but the black area is still influenced by lighting.
What is the simplest way to achieve a pure black that is not influenced by lighting? Do I have to use vertex+fragment shaders or can surface shaders do this?

I’m using the deferred rendering path.

(does the answer differ for forward rendering?)

2

Would the Final Color Modifier be what you need?

3

You also have to implement a custom lighting function for your surface shader. Add the same condition and return a black color.