在U3D中生成Cubemap所需要的六面图

功能：生成Cubemap所需要的六面图
脚本命：SkyBoxGenerator.js

使用方法：脚本必须放置在项目文件中名为“Editor”的文件夹；该脚本将创建一个名为“Custom/Render Skybox”菜单。当选定会弹出一个对话框，设置一个渲染位置然后点击“Render”，并等待几秒钟，刷新项目窗口，生成的6张图片将出现在名为“Skyboxes”的文件夹。警告，每次运行这个脚本，它会覆盖以前生成的图像。

脚本内容：
class SkyBoxGenerator extends ScriptableWizard
{
    var renderFromPosition : Transform;
   
    var skyBoxImage = new Array ("frontImage", "rightImage", "backImage", "leftImage", "upImage", "downImage");
   
    var skyDirection = new Array (Vector3 (0,0,0), Vector3 (0,-90,0), Vector3 (0,180,0), Vector3 (0,90,0), Vector3 (-90,0,0), Vector3 (90,0,0));
   
    
    function OnWizardUpdate()
    {
        helpString = "Select transform to render from";
        isValid = (renderFromPosition != null);
    }
   
    function OnWizardCreate()
    {
        var go = new GameObject ("SkyboxCamera", Camera);
       
        go.camera.backgroundColor = Color.black;
        go.camera.clearFlags = CameraClearFlags.Skybox;
        go.camera.fieldOfView = 90;   
        go.camera.aspect = 1.0;
       
        go.transform.position = renderFromPosition.position;
       
        if (renderFromPosition.renderer)
        {
            go.transform.position = renderFromPosition.renderer.bounds.center;
        }
       
        go.transform.rotation = Quaternion.identity;
       
        for (var orientation = 0; orientation < skyDirection.length ; orientation++)
        {
            renderSkyImage(orientation, go);
        }
 
        DestroyImmediate (go);
    }
   
    @MenuItem("Custom/Render Skybox", false, 4)
    static function RenderSkyBox()
    {
        ScriptableWizard.DisplayWizard ("Render SkyBox", SkyBoxGenerator, "Render!");
    }
   
    function renderSkyImage(orientation : int, go : GameObject)
    {
    go.transform.eulerAngles = skyDirection[orientation];
    var screenSize = 1024;
    var rt = new RenderTexture (screenSize, screenSize, 24);
    go.camera.targetTexture = rt;
    var screenShot = new Texture2D (screenSize, screenSize, TextureFormat.RGB24, false);
    go.camera.Render();
    RenderTexture.active = rt;
    screenShot.ReadPixels (Rect (0, 0, screenSize, screenSize), 0, 0);
       
    RenderTexture.active = null;
    DestroyImmediate (rt);
    var bytes = screenShot.EncodeToPNG();
       
    var directory = "Assets/Skyboxes";
    if (!System.IO.Directory.Exists(directory))
    System.IO.Directory.CreateDirectory(directory);
    System.IO.File.WriteAllBytes (System.IO.Path.Combine(directory, skyBoxImage[orientation] + ".png"), bytes);  
    }