Wednesday, November 14, 2012

Creating a Colored Unlit Texture Shader for Unity

When dealing with Unity materials, one easy and convenient feature is the ability to change the Main Color of a shader to tint the color of the texture it uses.  This can be used for a lot of different situations, like changing the color of a tile on a selection grid or changing the background color of a 2d game, to name a few.

Unfortunately I found the ability to specify a shader color missing in Unity's Unlit Texture shader.  The Unlit Texture shader isn't affected by lights, which is very convenient when you don't want to include lights in a scene or want to manually control the brightness of a texture.  It makes sense why the Unlit Texture shader doesn't include the color combiner support, the Unlit Texture shader is the simplest and fastest shader they have, and adding a color combiner would add extra instructions which would rarely be used.  Since I needed the ability to color tint an Unlit Texture for my new project, I decided to extend the existing Unlit Texture shader to support a color multiply operation.

The source for the new shader is below, you are free to copy it for your own needs*.  Use the 'Create--Shader' command in unity, then paste this code into the new file.  The shader will appear in the shader dropdown menu under NAKAI/Unlit/Texture Colored.  In case you're wondering, the Unlit Texture shader was written using Unity's ShaderLab Shader Syntax and I added a few extra lines to support the color combine operation.  Here's a picture of it in action, Enjoy!




// Unlit color shader. Very simple textured and colored shader.
// - no lighting
// - no lightmap support
// - per-material color

// Change this string to move shader to new location
Shader "NAKAI/Unlit/Texture Colored" {
    Properties {
        // Adds Color field we can modify
        _Color ("Main Color", Color) = (1, 1, 1, 1)        
        _MainTex ("Base (RGB)", 2D) = "white" {}
    }

    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 100
        
        Pass {
            Lighting Off
            
            SetTexture [_MainTex] { 
                // Sets our color as the 'constant' variable
                constantColor [_Color]
                
                // Multiplies color (in constant) with texture
                combine constant * texture
            } 
        }
    }
}


*You are free to use this for your own games.  Please do not sell it on the Unity asset store or anywhere else. :)

10 comments:

  1. This is Perfect, what I was looking for.
    Thank you.

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  2. thanks for sharing, plz add lightmap support too...

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  3. This comment has been removed by the author.

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  4. This comment has been removed by the author.

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  5. I'm making a point-click adventure game and your shader has been really helpful. Thanks a lot for sharing!

    I have a problem though, and I'd appreciate your help on that: I want to read the initial color of a mesh whose material I'm using your shader on.

    The command I'm using in the Start() function is:
    Color intialColor = getComponent().material.color;

    However, I always get the value of (1,1,1,1), which is the "Main Color" value you have defined in your shader.

    Is it possible to read the actual initial color of a mesh?

    Thanks in advance,

    Vasilis

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    Replies
    1. Unfortunately, HTML doesn't let me use the "less than" and "greater than" symbols... GetComponent is followed by "Renderer".

      Sorry for spamming your thread :)

      Delete
  6. I found a way out, eventually. It was a Unity bug having nothing to do with your shader after all. The solution came through this block of assignments:

    Renderer rend = GetComponent[Renderer] ();
    Color initialColor = rend.material.color;

    The Color assignment must take place immediately after the Renderer one, otherwise Color is set to (1,1,1,1).

    ReplyDelete
  7. Thank you so much! I modified your code to have transparency too!

    ReplyDelete
  8. Thank you so much! I modified your code to have transparency too!

    ReplyDelete
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    ReplyDelete