Weird behaviour of shader when saving a scene

Question

I wrote a custom Editor script for a class of mine to set colors to a material whenever any of the color values change, this gives me the option to preview the colors on the go.

The script works very well but when I save the scene there is something weird happening. All the colors change to some weird defaults and stay that way until I click on the object itself, then it gets updated to the correct colors that I chose before.

This is what the sprite looks like before I save the scene:

And here's what it looks like after I save the scene:

As I've mentioned, after I click on the GameObject, the sprite updates to previously saved colors.

Here's the code for the custom Editor script:

public class PaletteEditor : Editor
{
    SerializedProperty Col1,
        Col2,
        Col3,
        Col4;

    public void OnEnable()
    {
        Col1 = serializedObject.FindProperty("Col1");
        Col2 = serializedObject.FindProperty("Col2");
        Col3 = serializedObject.FindProperty("Col3");
        Col4 = serializedObject.FindProperty("Col4");
    }

    public override void OnInspectorGUI()
    {
        serializedObject.Update();

        Col1.colorValue = EditorGUILayout.ColorField("Col1", Col1.colorValue);
        Col2.colorValue = EditorGUILayout.ColorField("Col2", Col2.colorValue);
        Col3.colorValue = EditorGUILayout.ColorField("Col3", Col3.colorValue);
        Col4.colorValue = EditorGUILayout.ColorField("Col4", Col4.colorValue);

        ((ColorMatrixPicker)target).SetColorMatrix();
        serializedObject.ApplyModifiedProperties();
    }
}

EDIT:

I've tried SonicBlue22's solution but the problem still persists. I've fiddled around with the script and I think the problem might be with the shader itself as it does not keep the values assigned to it by the script.

Here's the shader code:

Shader "Custom/PaletteSwap" {
Properties{
    _Color("Color", Color) = (1,1,1,1)
    [PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
    _Cutoff("Shadow alpha cutoff", Range(0,1)) = 0.5
    _BumpTex("Bump map", 2D) = "bump" {}
}
SubShader
{
    Tags
    {
        "Queue" = "Geometry"
        "RenderType" = "TransparentCutout"
    }

    Cull Off

    CGPROGRAM
    #pragma surface surf Lambert addshadow fullforwardshadows
    #pragma target 3.0

    sampler2D _MainTex;
    sampler2D _BumpTex;
    fixed4 _Color;
    fixed _Cutoff;
    half4x4 _ColorMatrix;

    struct Input
    {
        float2 uv_MainTex;
    };

    void surf(Input IN, inout SurfaceOutput o) {
        fixed4 c = tex2D(_MainTex, IN.uv_MainTex);
        o.Normal = UnpackNormal(tex2D(_BumpTex, IN.uv_MainTex));
        o.Albedo = _ColorMatrix[c.r * 3];
        o.Alpha = c.a;
        clip(o.Alpha - _Cutoff);
    }
    ENDCG
}
FallBack "Diffuse"

}

I assign the color values straight to the matrix like so:

Mat.SetMatrix("_ColorMatrix", ColorMatrix);

Where ColorMatrix is a Property that generates Matrix4x4.

Does anyone know how to make the colors persist inside the shader?

Answer 1

Move SetColorMatrix(); from OnInspectorGUI() in the editor to OnValidate() in the script.

public class ColorMatrixPicker : MonoBehavior {
    private void OnValidate() {
        SetColorMatrix();
    }
}

If that doesn't work, add [ExecuteInEditMode] before the class declaration and also add SetColorMatrix() to Start().