Accessing components of a property in ShaderLab

Unity Engine
1

I am trying to accomplish the following:

	Properties {
		_Color ("Color", Color) = (1,1,1,1)
	}
	:
	:
			SetTexture [_] {
				constantColor ( 0, 0, 0, _Color.alpha / 3f ) <-- This line report syntax errors
				combine constant lerp( constant ) previous 
			}

I can’t find any documentation pertaining to this.

I guess if it was the only combiner, then I could stick one in front of it that multiplies _Color by 0,0,0,1/3 and then the value I want would be in the alpha channel of previous

but I have combiners in front. So is there some direct way to accomplish this?

π

2

I don’t believe it’s possible to do this. I can’t find anyone doing this on the Internet, and the documentation doesn’t suggest it is possible.

3

As far as I know, this isn’t possible.

4

I always thought that it was done by using color.a, or whatever colour you can think of.

5

Yes, but not in fixed function shaders.

6

Ah, thank you.