Shader: Creating a shader that acts like Photoshops 'Color' blendingmode

[system]

Hello there,

I am having trouble creating a shader that behaves like the ‘Color’ layer effect in Photoshop. I have Googled my ass of to find a decent shader for this but it lead to nowhere.

What I want to achieve is the following: I have gray-scaled images for my menu buttons and I want to colorize the gray areas in the image. The default shaders like ‘Transparent/Diffuse’ is almost what I want except that it also colorizes the white pixels, and I only need the gray areas to colorize.

I am stuck with this. Is there anybody who can help me? I basicly need a shader with one texture input and one colour input that automagicly combines the two into what I need.

In the following image you can see what I am trying to achieve:

[Lex]

Well I’m hope it’s not too late for you but I think I might have found the solution for this:

Just use this Shader that is a modified version of Unlit Transparent Colored and copies the Photoshop’s Overlay behavior on Layers.

Shader "Unlit/Photoshop Overlay"
{
    Properties
    {
        _MainTex ("Base (RGB), Alpha (A)", 2D) = "" {}
    }
    
    SubShader
    {
        LOD 100

        Tags
        {
            "Queue" = "Transparent"
            "IgnoreProjector" = "True"
            "RenderType" = "Transparent"
        }
        
        Pass
        {
            Cull Off
            Lighting Off
            ZWrite Off
            Fog { Mode Off }
            Offset -1, -1
            ColorMask RGB
            AlphaTest Greater .01
            Blend SrcAlpha OneMinusSrcAlpha
            ColorMaterial AmbientAndDiffuse
            
            SetTexture [_MainTex]
            {
                Combine Texture +- Primary, Texture * Primary
            }
            
            SetTexture [_MainTex]
            {
                Combine Texture +- previous, Texture * Primary
            }
        }
    }
}

Good luck.

[system]

Have a look at the code here: Photoshop math with GLSL shaders | Projects, Software, Programming, GLSL - Romz Blog - but essentially you convert to the HueSaturationLuminance (HSL)-colorspace, and replace the Hue with your input hue.

[radiowaves]

“Overlay” is not “color” these act very differently in Photoshop. Overlay is additive, it makes tings lighter (closer to white), color leaves sum RGB value the same.

For example I need a shader that makes things monochrome. In photoshop I create a white colour layer and issue blending mode “color”, this makes it grayscale. Next I make another color blending layer with a desired colour.