任意の解像度でCubemapを作って保存するEditorスクリプト

RenderCubemapWizard.cs

// http://docs.unity3d.com/ja/current/ScriptReference/Camera.RenderToCubemap.html
// http://stackoverflow.com/questions/34458622/unity-save-cubemap-to-one-circle-image
using UnityEngine;
using UnityEditor;
using System.Linq;
using System.IO;

public class RenderCubemapWizard : ScriptableWizard
{

    public Camera camera;
    public int cubeMapSize = 2048;

    void OnWizardUpdate()
    {
        bool isValid = (camera != null);
    }

    void OnWizardCreate()
    {
        if (camera == null)
        {
            camera = Camera.main;
        }

        Cubemap cu = new Cubemap(cubeMapSize, TextureFormat.RGB24, false);

        camera.RenderToCubemap(cu);
        cu.Apply();

        var path = EditorUtility.SaveFilePanel("CubeMap", "", "", "cubemap");
        if (!string.IsNullOrEmpty(path))
        {
            Debug.Log("path " + path);

            ConvertToPng(cu, path);
        }
    }

    [MenuItem("GameObject/Render into Cubemap")]
    static void RenderCubemap()
    {
        ScriptableWizard.DisplayWizard<RenderCubemapWizard>(
            "Render cubemap", "Render!");
    }

    void ConvertToPng(Cubemap cube, string path)
    {
        string dir = Path.GetDirectoryName(path);
        string filename = Path.GetFileNameWithoutExtension(path);
        string dir2 = dir.Replace(Application.dataPath, "");
        dir2 = "Assets" + dir2;
        Debug.Log("dir " + dir + " filename " + filename);
        Debug.Log("Application.dataPath " + Application.dataPath);
        Debug.Log("dir2 " + dir2);

        // Save Cubemap
        string cubeMapPath = dir2 + "/" + filename + ".cubemap";
        var asset = AssetDatabase.LoadAssetAtPath(cubeMapPath, typeof(Cubemap));
        if (asset == null)
        {
            AssetDatabase.CreateAsset(cube, cubeMapPath);
        }
        else
        {
            EditorUtility.CopySerialized(cube, asset);
            AssetDatabase.SaveAssets();
        }

        // Save Plane Texture
        var tex = new Texture2D(cube.width, cube.height, TextureFormat.RGB24, false);
        var bytes = getPlanePixels(tex, CubemapFace.PositiveX, cube);
        File.WriteAllBytes(dir + "/" + filename + "_PositiveX.png", bytes);

        bytes = getPlanePixels(tex, CubemapFace.NegativeX, cube);
        File.WriteAllBytes(dir + "/" + filename + "_NegativeX.png", bytes);

        bytes = getPlanePixels(tex, CubemapFace.PositiveY, cube);
        File.WriteAllBytes(dir + "/" + filename + "_PositiveY.png", bytes);

        bytes = getPlanePixels(tex, CubemapFace.NegativeY, cube);
        File.WriteAllBytes(dir + "/" + filename + "_NegativeY.png", bytes);

        bytes = getPlanePixels(tex, CubemapFace.PositiveZ, cube);
        File.WriteAllBytes(dir + "/" + filename + "_PositiveZ.png", bytes);

        bytes = getPlanePixels(tex, CubemapFace.NegativeZ, cube);
        File.WriteAllBytes(dir + "/" + filename + "_NegativeZ.png", bytes);

        DestroyImmediate(tex);
        AssetDatabase.Refresh();
    }

    byte[] getPlanePixels(Texture2D _tex, CubemapFace _face, Cubemap cube)
    {
        Texture2D tmpTex = new Texture2D(cube.width, cube.height, TextureFormat.RGB24, false);
        tmpTex.SetPixels(cube.GetPixels(_face));
        Color[] vline;
        for (int x = 0; x < cube.width; ++x)
        {
            vline = tmpTex.GetPixels(x, 0, 1, cube.height);
            _tex.SetPixels(x, 0, 1, cube.height, vline.Reverse().ToArray());
        }
        return _tex.EncodeToPNG();
    }

}