color replacement shader

Hello!

I try to achieve a comic-style look with simple animations by changing the color.
Therefor i wrote (copied) a very simple subshader with 2 textures.
The first one is a grayscale image and the second one maps the gray-values to color-values. (y: gray-value, x:timeline)

Code (CSharp):

1. Shader "Cg shader using blending" {
2.     Properties {
3.         _MainTex ("Greyscale (R) Alpha (A)", 2D) = "white" {}
4.         _ColorRamp ("Colour Palette", 2D) = "gray" {}
5.         _SampleTime ("Sample Time", Float) = 0.0
6.         }
7.        
8.    SubShader {
9.       Tags { "Queue" = "Transparent" }
10.          // draw after all opaque geometry has been drawn
11.       Pass {
12.          ZWrite Off // don't write to depth buffer
13.             // in order not to occlude other objects
14.          Blend SrcAlpha OneMinusSrcAlpha // use alpha blending
15.          CGPROGRAM
16.          #pragma vertex vert
17.          #pragma fragment frag
18.         #pragma fragmentoption ARB_precision_hint_fastest
19.         #include "UnityCG.cginc"
20.      
21.         struct v2f
22.         {
23.             float4  pos : SV_POSITION;
24.             float2  uv : TEXCOORD0;
25.         };
26.  
27.         v2f vert (appdata_tan v)
28.         {
29.             v2f o;
30.             o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
31.             o.uv = v.texcoord.xy;
32.             return o;
33.         }
34.      
35.         sampler2D _MainTex;
36.         sampler2D _ColorRamp;
37.         float _SampleTime;
38.         float4 frag(v2f i) : COLOR
39.         {
40.         // SURFACE COLOUR
41.             float greyscale = tex2D(_MainTex, i.uv).r;
42.      
43.         // RESULT
44.             float4 result;
45.             result = tex2D(_ColorRamp, float2(_SampleTime, greyscale));
46.             //result.a = tex2D(_MainTex, i.uv).a;
47.             return result;
48.         }
49.          ENDCG
50.       }
51.    }
52. }

The first problem was the antialiasing of the png, which i solved.
Unfortunately there remains an artefact between the colors.



This is especially annoying when i use transparency or when i want to "hide" an element by using the same color...
If anyone can give me a hint to solve this, i would be very glad.

Thank you very much for reading this

 

I found a solution...
Now i use the r, g and b channels of the image to seperate the different regions.
I want at least 6 different regions, so i use 2 textures and one for color mapping.

Code (CSharp):

1. Shader "ColorReplacment" {
2.     Properties {
3.         _ColorRamp ("Color Ramp", 2D) = "gray" {}
4.         _MainTex1 ("Main Texture 1", 2D) = "white" {}
5.         _MainTex2 ("Main Texture 2", 2D) = "white" {}
6.         }
7.      
8.    SubShader {
9.       Tags { "Queue" = "Transparent" }
10.          // draw after all opaque geometry has been drawn
11.       Pass {
12.          //ZWrite Off
13.        
14.          Blend SrcAlpha OneMinusSrcAlpha // use alpha blending
15.          CGPROGRAM
16.          #pragma vertex vert
17.          #pragma fragment frag
18.  
19.         #include "UnityCG.cginc"
20.  
21.         sampler2D _MainTex1;
22.         sampler2D _MainTex2;
23.         sampler2D _ColorRamp;      
24.         half _SampleTime;
25.      
26.         v2f_img vert(appdata_base v)
27.         {
28.             v2f_img o;
29.             o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
30.             o.uv = v.texcoord.xy;
31.             return o;
32.         }
33.         fixed4 frag(v2f_img i) : COLOR
34.         {
35.         // Surface
36.             fixed4 main1 = tex2D(_MainTex1, i.uv);
37.             fixed4 main2 = tex2D(_MainTex2, i.uv);
38.      
39.         // RESULT
40.             fixed4 result1 = tex2D(_ColorRamp, half2(_SampleTime,half(0.0625))) * main1.r + tex2D(_ColorRamp, half2(_SampleTime,half(0.4375))) * main2.r;
41.             fixed4 result2 = tex2D(_ColorRamp, half2(_SampleTime,half(0.1875))) * main1.g + tex2D(_ColorRamp, half2(_SampleTime,half(0.5625))) * main2.g;
42.             fixed4 result3 = tex2D(_ColorRamp, half2(_SampleTime,half(0.3125))) * main1.b + tex2D(_ColorRamp, half2(_SampleTime,half(0.6875))) * main2.b;
43.  
44.             fixed4 result = result1 + result2 + result3;
45.  
46.             return result;
47.         }
48.        ENDCG
49.    }
50.    }
51. }
52.  
53.  

This also solved the problem with the antialiasing.
But i guess, this is not the best solution for what i want to do.
So, if anybody has a better approach...