Unity player transparent background on iOS

Is it possible to make the background of the unity player transparent on iOS?
I want to put a native view behind the unity view.

I was able to do it on Android (using the tutorial in http://www.geekyhamster.com/2013/07/unityplayer-as-subview-with-transparent.html), but haven't been able to find a way to do it on iOS.

I found a few posts on forums saying it is possible to make the CAEAGLLayer transparent using the following code:
CAEAGLLayer* layer = (CAEAGLLayer*)eaglLayer;
layer.opaque = NO;
layer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking,
kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat,
nil
];

I added this in the OpenEAGL_UnityCallback method of UnityAppController.mm as follows:

_mainDisplay->surface.layer.opaque = NO;
_mainDisplay->surface.layer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking,
kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat,
nil
];

And putting the camera background color to (0,0,0,0).

But it's still not working.

 

I found the solution.
I placed the following code in DisplayManager.mm in the method - (void)recreateSurfaceBOOL)use32bitColor use24bitDepthBOOL)use24bitDepth msaaSampleCountint)msaaSampleCount renderWint)renderW renderHint)renderH :

Code (csharp):

1. surface.layer.opaque = NO;
2.     surface.layer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
3.                                                       [NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking,
4.                                                       kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat,
5.                                                       nil
6.                                                       ];

And it worked.

 

Hi Dan and thanks for your post

I tried to do the same. But using the code that is already inside GlesHelper.mm

Code (csharp):

1.  
2. void CreateSystemRenderingSurface(UnityRenderingSurface* surface)
3. {
4.     EAGLContextSetCurrentAutoRestore autorestore(surface->context);
5.     DestroySystemRenderingSurface(surface);
6.  
7.     const NSString* colorFormat = surface->use32bitColor ? kEAGLColorFormatRGBA8 : kEAGLColorFormatRGB565;
8.  
9.     surface->layer.opaque = NO;
10.     surface->layer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
11.                                             [NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking,
12.                                             colorFormat, kEAGLDrawablePropertyColorFormat,
13.                                             nil
14.                                         ];
15. ...
16.  

MY background is then transparent. But! I have some weird artifacts with semi-transparent items like the water when in front of a strongly coloured UIView. Which clear flags are you using in your camera? A solid transparent color or depth only?

 

All I can see that you changed was at "surface->layer.opaque" you changed YES to NO. So I tried this and didn't observe a change. Also tried changing my camera's Clear Flags to depth only and that only made the background black but not transparent.
Any ideas?
And did you solve the issue you still had?
Thanks!

 

On iOS with Metal API you have to change the file MetalHelper.mm to:

CGFloat backgroundColor[] = {0,0,0,0};

and add

surface->layer.opaque = NO;

Works for me on Uniti 5.2.

See the comments I made here:
http://www.geekyhamster.com/2013/12/unityplayer-as-subview-with-transparent.html