unity3d GUI上显示3d模型

我们的游戏选择角色的时候需要在2d GUI的上层显示3d模型，默认3d模型是显示在2d GUI下面的，所以需要另外创建一个Camera,并且把新建的Camera 设置 target 到 RenderTexture，然后把这个RenderTexture显示到GUI上就行了。

代码如下：

Create Camera:

_myObject = new GameObject(_Name, typeof(Camera), typeof(Skybox));
_myCamera = _myObject.camera;
_myCamera .depth = 2;
_myCamera .clearFlags = CameraClearFlags.Skybox;
_myCamera .backgroundColor = Color.clear;//Color.black;
_myCamera .nearClipPlane = 0.3f;
_myCamera .fieldOfView = 60;
_myCamera .orthographicSize = 100.0f;

Create RenderTexture:

private static void InitTexture(int with, int height)
{
// _myTexture = new RenderTexture(with, height, 2);

_myTexture= RenderTexture.GetTemporary(with, height, 0, RenderTextureFormat.ARGB32);
_myTexture.name = "storyTexture" + _storyObject.GetInstanceID();
_myTexture.isPowerOfTwo = false;
_myTexture.targetTexture = _storyTexture;
}

Draw RenderTexture:

//GUI.DrawTexture(new Rect(0, 0, Screen.width, Screen.height), _storyTexture,ScaleMode.StretchToFill);

GUI.DrawTexture(new Rect(0, 0, Screen.width, Screen.height), _storyTexture,ScaleMode.ScaleToFit);

移动端有一些需要注意的地方：

1、创建RenderTexture的时候，如果直接new到iphone上背景就是黑的，晚上找到解决办法如下：

When setting up the Camera object, a RenderTexture is needed as the targetTexture for rendering. If you use a dynamically created Camera, you have one by default whose depth is 24. But it seems iOS devices only support depth = 0, so there are some problems.

To walk around, add a statement like this:

myCamera.targetTexture = RenderTexture.GetTemporary(myWidth, myHeight, 0, myFormat);

where the third parameter is the depth of the RenderTexture.

2、把RenderTexture画到屏幕上的时候，如果选择StretchToFill，手机上就会，需要选择ScaleToFit