カスタム マテリアルエディタ

シェーダを使用する場合に,興味深いデータタイプがあり,Unity ビルトイン シェーダで綺麗に再現できる場合があります。Unityにはデフォルトのマテリアル インスペクタを自身で定義できるようにオーバライドできる方法が用意されています。この機能を用いてカスタムのコントロールおよびデータ範囲のバリデーションをを定義できます。

カスタムのマテリアル エディタを記述する最初の部分は, カスタム エディタ を必要とするシェーダを定義することです。カスタム エディタで使用する名前は Unity でマテリアルエディタをルックアップするときのクラス名です。

カスタム エディタを定義するには,MaterialEditor クラスを拡張し,スクリプトを Assets ディレクトリの中の Editor フォルダにスクリプトを配置します。

using UnityEditor;

public class CustomMaterialInspector : MaterialEditor {
    public override void OnInspectorGUI () {
        base.OnInspectorGUI ();
    }
}

Any shader that has a custom editor defined (CustomEditor “CustomMaterialInspector”) will find the editor listed above and execute the associated code.

A real example

So we have a situation where we have a shader that can work in two modes; it renders standard diffuse lighting or it only renders the red components of the source texture. This is achieved using shader multi compilation.

Shader "Custom/Redify" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200
        
        CGPROGRAM
        #pragma surface surf Lambert
        #pragma multi_compile REDIFY_ON REDIFY_OFF

        sampler2D _MainTex;

        struct Input {
            float2 uv_MainTex;
        };

        void surf (Input IN, inout SurfaceOutput o) {
            half4 c = tex2D (_MainTex, IN.uv_MainTex);
            o.Albedo = c.rgb;
            o.Alpha = c.a;


    #if REDIFY_ON
            o.Albedo.gb = (o.Albedo.g + o.Albedo.b) / 2.0;

    #endif
        }
        ENDCG
    } 
    FallBack "Diffuse"
    CustomEditor "CustomMaterialInspector"
}

As you can see the shader has two Keywords available for setting: REDIFY_ON and REDIFY_OFF. These can be changed be set on a per material basis by using the shaderKeywords property of the material. below is an editor that does this.

using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.Linq;

public class CustomMaterialInspector : MaterialEditor {

    public override void OnInspectorGUI ()
    {
        // render the default inspector
        base.OnInspectorGUI ();

        // if we are not visible... return
        if (!isVisible)
            return;

        // get the current keywords from the material
        Material targetMat = target as Material;
        string[] keyWords = targetMat.shaderKeywords;

        // see if redify is set, then show a checkbox
        bool redify = keyWords.Contains ("REDIFY_ON");
        EditorGUI.BeginChangeCheck();
        redify = EditorGUILayout.Toggle ("Redify material", redify);
        if (EditorGUI.EndChangeCheck())
        {
            // if the checkbox is changed, reset the shader keywords
            var keywords = new List<string> { redify ? "REDIFY_ON" : "REDIFY_OFF"};
            targetMat.shaderKeywords = keywords.ToArray ();
            EditorUtility.SetDirty (targetMat);
        }
    }
}

How the default material editor works

The default Unity editor renders all the properties that exist in a shader to the the material editor. Below is a custom material editor that behaves similar to the Unity material editor. Use this example if you wish to manually render the default fields.

using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.Linq;

public class CustomMatInspector : MaterialEditor {

    // this is the same as the ShaderProperty function, show here so 
    // you can see how it works
    private void ShaderPropertyImpl(Shader shader, int propertyIndex)
    {
        int i = propertyIndex;
        string label = ShaderUtil.GetPropertyDescription(shader, i);
        string propertyName = ShaderUtil.GetPropertyName(shader, i);
        switch (ShaderUtil.GetPropertyType(shader, i))
        {
            case ShaderUtil.ShaderPropertyType.Range: // float ranges
            {
                GUILayout.BeginHorizontal();
                float v2 = ShaderUtil.GetRangeLimits(shader, i, 1);
                float v3 = ShaderUtil.GetRangeLimits(shader, i, 2);
                RangeProperty(propertyName, label, v2, v3);
                GUILayout.EndHorizontal();

                break;
            }
            case ShaderUtil.ShaderPropertyType.Float: // floats
            {
                FloatProperty(propertyName, label);
                break;
            }
            case ShaderUtil.ShaderPropertyType.Color: // colors
            {
                ColorProperty(propertyName, label);
                break;
            }
            case ShaderUtil.ShaderPropertyType.TexEnv: // textures
            {
                ShaderUtil.ShaderPropertyTexDim desiredTexdim = ShaderUtil.GetTexDim(shader, i);
                TextureProperty(propertyName, label, desiredTexdim);

                GUILayout.Space(6);
                break;
            }
            case ShaderUtil.ShaderPropertyType.Vector: // vectors
            {
                VectorProperty(propertyName, label);
                break;
            }
            default:
            {
                GUILayout.Label("ARGH" + label + " : " + ShaderUtil.GetPropertyType(shader, i));
                break;
            }
        }
    }

    public override void OnInspectorGUI ()
    {
        serializedObject.Update ();
        var theShader = serializedObject.FindProperty ("m_Shader"); 
        if (isVisible && !theShader.hasMultipleDifferentValues && theShader.objectReferenceValue != null)
        {
            float controlSize = 64;

            EditorGUIUtility.LookLikeControls(Screen.width - controlSize - 20);

            EditorGUI.BeginChangeCheck();
            Shader shader = theShader.objectReferenceValue as Shader;

            for (int i = 0; i < ShaderUtil.GetPropertyCount(shader); i++)
            {
                ShaderPropertyImpl(shader, i);
            }

            if (EditorGUI.EndChangeCheck())
                PropertiesChanged ();
        }
    }
}