Modifying my shader to overlay rather than blend.

Questions & Answers
1

Hiya all.

I've modified the LayerShader from Unify so that it maps two textures (with alphas) to one mesh using two different UV maps.

Is there any way I could modify it so that instead of combining MainTex with PathTex, it overlays MainTex over PathTex? The source is below:

Shader "DoubleUV2" { 

Properties {
    _Color ("Color", Color) = (1,1,1)
    _Blend ("Blend", Range (0,1)) = 0.5 
    _MainTex ("Main Texture", 2D) = "" 
    _PathTex ("Path Texture (RGB)", 2D) = ""

}

Category {
    Material {
        Ambient[_Color]
        Diffuse[_Color]
    }

    SubShader {
        Pass {
        BindChannels
        {
            Bind "Vertex", vertex         
            Bind "texcoord1", texcoord0
            Bind "texcoord", texcoord1
            Bind "Color", color
            Bind "Normal", normal
        }

            SetTexture[_PathTex]

            SetTexture[_MainTex]
            {
                combine texture * previous, previous + texture
            }

        }

        Pass {
            Lighting On
            Blend DstColor SrcColor
        }
    }
}

}

Regards, Joel.

2

You should really check the docs on Texturing in ShaderLab.

In the example there, they define a texture blend shader with

combine texture lerp (texture) previous

There are any number of kinds of functions you can use for combining textures and your use of terminology is unspecific.

//multiply (what you're already doing)
combine texture * previous

//add
combine texture + previous

//Alpha blend (previous's alpha will be used to blend previous over texture).
combine previous lerp(previous) texture

Based on the fact that you have a "blend" property, it would seem you want to control using that property. I did something like that here.

SetTexture[_PathTex]
SetTexture[_MainTex]
{
    ConstantColor (0,0,0, [_Blend])
    combine previous lerp(constant) texture
}

or if you wanted it to be more of an additive combiner, you could do something like:

SetTexture[_PathTex]
SetTexture[_MainTex]
{
    ConstantColor ([_Blend],[_Blend],[_Blend],[_Blend])
    combine previous * constant + texture
}