ChunilENG/Assets/Editor/ReplacePrefabMaterials.cs

using UnityEngine;
using UnityEditor;

public class ReplacePrefabMaterials : EditorWindow
{
    private GameObject targetGameObject;
    private Material materialToFind;
    private Material materialToReplace;

    [MenuItem("Tools/Replace Prefab Materials")]
    public static void ShowWindow()
    {
        GetWindow<ReplacePrefabMaterials>("Replace Prefab Materials");
    }

    private void OnGUI()
    {
        GUILayout.Label("Replace Materials in Prefabs", EditorStyles.boldLabel);

        targetGameObject = (GameObject)EditorGUILayout.ObjectField("Target Game Object", targetGameObject, typeof(GameObject), true);

        materialToFind = (Material)EditorGUILayout.ObjectField("Material to Find", materialToFind, typeof(Material), false);
        materialToReplace = (Material)EditorGUILayout.ObjectField("Material to Replace", materialToReplace, typeof(Material), false);

        if (GUILayout.Button("Replace Selected Prefabs"))
        {
            ReplaceTargetObjectMaterials();
        }

        if (GUILayout.Button("Replace in All Prefabs"))
        {
            ReplaceAllPrefabMaterials();
        }
    }

    private void ReplaceTargetObjectMaterials()
    {
        if (materialToFind == null || materialToReplace == null)
        {
            Debug.LogError("Please assign both materials.");
            return;
        }

        if (targetGameObject == null)
        {
            Debug.LogError("Please assign the target GameObject.");
            return;
        }

        Renderer[] renderers = targetGameObject.GetComponentsInChildren<Renderer>(true);
        bool isDirty = false;
        int count = 0;

        foreach (Renderer renderer in renderers)
        {
            Material[] materials = renderer.sharedMaterials;
            for (int i = 0; i < materials.Length; i++)
            {
                if (materials[i] == materialToFind)
                {
                    materials[i] = materialToReplace;
                    isDirty = true;
                    count++;
                }
            }
            if (isDirty)
            {
                renderer.sharedMaterials = materials;
            }
        }

        if (isDirty)
        {
            EditorUtility.SetDirty(targetGameObject);
            Debug.Log(count + "Complete");
        }
        else
        {
            Debug.Log($"No instances of {materialToFind.name} found in the target GameObject.");
        }
    }

    private void ReplaceAllPrefabMaterials()
    {
        if (materialToFind == null || materialToReplace == null)
        {
            Debug.LogError("Please assign both materials.");
            return;
        }

        int count = 0;
        string[] prefabGuids = AssetDatabase.FindAssets("t:Prefab");
        foreach (string prefabGuid in prefabGuids)
        {
            string prefabPath = AssetDatabase.GUIDToAssetPath(prefabGuid);
            GameObject prefab = AssetDatabase.LoadAssetAtPath<GameObject>(prefabPath);

            if (prefab != null)
            {
                Renderer[] renderers = prefab.GetComponentsInChildren<Renderer>(true);
                bool isDirty = false;

                foreach (Renderer renderer in renderers)
                {
                    Material[] materials = renderer.sharedMaterials;
                    for (int i = 0; i < materials.Length; i++)
                    {
                        if (materials[i] == materialToFind)
                        {
                            materials[i] = materialToReplace;
                            isDirty = true;
                            count++;
                        }
                    }
                    if (isDirty)
                    {
                        renderer.sharedMaterials = materials;
                    }
                }

                if (isDirty)
                {
                    EditorUtility.SetDirty(prefab);
                    PrefabUtility.SavePrefabAsset(prefab);
                }
            }
            else
            {
                Debug.Log("Null");
            }
        }

        Debug.Log($"Replaced {count} instances of {materialToFind.name} with {materialToReplace.name} in prefabs.");
    }
}