Shader dynamic color in Pass

Questions & Answers
1

I have this shader

    Shader "Custom/ShowThrough" {
        Properties {
            _Color ("Main Color", Color) = (1,1,1,1)
            _MainTex ("Base (RGB)", 2D) = "white" {}
    		_OccludeColor ("Occlusion Color", Color) = (0,0,0,1)
        }
        SubShader {
            Tags {"Queue"="Geometry+5"}
            // occluded pass
            Pass {
                ZWrite Off
                Blend One Zero
                ZTest Greater
                Color [_OccludeColor]
            }
            // Vertex lights
            Pass {
                Tags {"LightMode" = "Vertex"}
                ZWrite On
                Lighting On
                SeparateSpecular On
                Material {
                    Diffuse [_Color]
                    Ambient [_Color]
                    // Emission [_PPLAmbient]
                }
                SetTexture [_MainTex] {
                    ConstantColor [_Color]
                    Combine texture * primary DOUBLE, texture * constant
                }
            }
        }
        FallBack "Diffuse", 1
    }

I want instead of

Color [_OccludeColor]

to use something like

Color (_Color.r/2,_Color.g/2,_Color.b/2, 1)

in pass, so it is

        Pass {
            ZWrite Off
            Blend One Zero
            ZTest Greater
            Color (_Color.r/2,_Color.g/2,_Color.b/2, 1)
        }

but the syntax is not right, what would be the right syntax?

2

You can’t put this line here, you must put it in a d surface or fragment shader !
This part (fragment or surface) allow you to be specific about how to render pixel color of your model !

P.S: Try surface function in shader it’s more easily, this function calculate for you the light.