EditorVoxMaps

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

public class EditorVoxMaps : EditorWindow
{
    [MenuItem("Tools/Voxel Material")]
    private static void ShowEditor()
    {
        EditorVoxMaps win = EditorWindow.GetWindow<EditorVoxMaps>("Voxel Material");
        win.Show();
    }

    private class VoxMat
    {
        public float metallic;
        public float smooth;
        public bool emission;
    }

    private Dictionary<Color, VoxMat> colors = new Dictionary<Color, VoxMat>();

    private Renderer rend;
    private Texture2D colorTexture;
    private Texture2D metallicTexture;
    private Texture2D emissionTexture;

    private void Awake()
    {
        OnSelectionChange();
    }

    private void OnInspectorUpdate()
    {
        Repaint();
    }

    private void InvalidateMesh()
    {
        colors.Clear();
        rend = null;
        colorTexture = null;
        metallicTexture = null;
        emissionTexture = null;
    }

    private void OnSelectionChange()
    {
        InvalidateMesh();

        GameObject go = Selection.activeGameObject;
        if (go == null) return;

        rend = go.GetComponent<Renderer>();
        if (rend == null) return;

        UpdateSelected();
    }

    private void UpdateSelected()
    {
        colorTexture = GetReadableTexture(rend.sharedMaterial.mainTexture);
        if (colorTexture == null)
        {
            InvalidateMesh();
            return;
        }

        metallicTexture = GetReadableTexture(rend.sharedMaterial.GetTexture("_MetallicGlossMap"));
        if (metallicTexture != null)
        {
            if (metallicTexture.width != colorTexture.width || metallicTexture.height != colorTexture.height)
            {
                InvalidateMesh();
                return;
            }
        }

        emissionTexture = GetReadableTexture(rend.sharedMaterial.GetTexture("_EmissionMap"));
        if (emissionTexture != null)
        {
            if (emissionTexture.width != colorTexture.width || emissionTexture.height != colorTexture.height)
            {
                InvalidateMesh();
                return;
            }
        }

        for (int y = 0; y < colorTexture.height; y++)
        {
            for (int x = 0; x < colorTexture.width; x++)
            {
                Color c = colorTexture.GetPixel(x, y);
                if (colors.ContainsKey(c)) continue;

                VoxMat vm = new VoxMat();

                if (metallicTexture != null)
                {
                    Color mc = metallicTexture.GetPixel(x, y);
                    vm.metallic = mc.r;
                    vm.smooth = mc.a;
                }
                if (emissionTexture != null)
                {
                    Color ec = emissionTexture.GetPixel(x, y);
                    if (ec != Color.black) vm.emission = true;
                }

                colors.Add(c, vm);
            }
        }

        if (colors.Count > 256) InvalidateMesh();
    }

    private Texture2D GetReadableTexture(Texture source)
    {
        if (source == null) return null;

        RenderTexture tmp = RenderTexture.GetTemporary(source.width, source.height, 0, RenderTextureFormat.Default, RenderTextureReadWrite.Linear);
        Graphics.Blit(source, tmp);

        RenderTexture previous = RenderTexture.active;
        RenderTexture.active = tmp;

        Texture2D myTexture2D = new Texture2D(source.width, source.height);
        myTexture2D.ReadPixels(new Rect(0, 0, tmp.width, tmp.height), 0, 0);
        myTexture2D.Apply();

        RenderTexture.active = previous;
        RenderTexture.ReleaseTemporary(tmp);

        return myTexture2D;
    }

    private void BakeTextures()
    {
        if (colorTexture == null) return;

        Texture2D mt = new Texture2D(colorTexture.width, colorTexture.height, TextureFormat.RGBA32, false);
        mt.filterMode = FilterMode.Point;

        Texture2D et = new Texture2D(colorTexture.width, colorTexture.height, TextureFormat.RGBA32, false);
        et.filterMode = FilterMode.Point;

        for (int y = 0; y < colorTexture.height; y++)
        {
            for (int x = 0; x < colorTexture.width; x++)
            {
                Color c = colorTexture.GetPixel(x, y);
                float m = colors[c].metallic;
                float s = colors[c].smooth;

                mt.SetPixel(x, y, new Color(m, 0, 0, s));
                if (colors[c].emission)
                    et.SetPixel(x, y, c);
                else
                    et.SetPixel(x, y, Color.black);
            }
        }
        mt.Apply();
        et.Apply();

        rend.sharedMaterial.SetTexture("_MetallicGlossMap", mt);

        rend.sharedMaterial.EnableKeyword("_EMISSION");
        rend.sharedMaterial.SetTexture("_EmissionMap", et);
        rend.sharedMaterial.SetColor("_EmissionColor", Color.white);
        rend.sharedMaterial.globalIlluminationFlags = MaterialGlobalIlluminationFlags.BakedEmissive;

        //Todo: Proper saving....
        string n = rend.gameObject.transform.root.name;
        AssetDatabase.CreateAsset(mt, "Assets/" + n + "_m.asset");
        AssetDatabase.CreateAsset(et, "Assets/" + n + "_e.asset");
        AssetDatabase.Refresh();
    }

    private Vector2 scroll;

    private void OnGUI()
    {
        if (rend == null || colors.Keys.Count == 0)
        {
            GUILayout.Label("Plese Select Voxel Mesh");
            return;
        }

        if (GUILayout.Button("Bake Maps")) BakeTextures();

        List<Color> keys = new List<Color>(colors.Keys);

        scroll = GUILayout.BeginScrollView(scroll);

        foreach (Color c in keys)
        {
            GUILayout.BeginHorizontal();
            GUI.backgroundColor = c;
            GUILayout.Box(GUIContent.none, GUILayout.Width(25), GUILayout.Height(15));

            GUILayout.BeginHorizontal();
            colors[c].metallic = GUILayout.HorizontalSlider(colors[c].metallic, 0, 1);
            colors[c].smooth = GUILayout.HorizontalSlider(colors[c].smooth, 0, 1);
            colors[c].emission = GUILayout.Toggle(colors[c].emission, GUIContent.none, GUILayout.Width(20));
            GUILayout.EndHorizontal();

            GUILayout.EndHorizontal();
        }

        GUILayout.EndScrollView();
    }
}