1037885 - Can't sample from packaged apps' icons in WebGL

Status: RESOLVED INVALID

(Core :: Graphics: CanvasWebGL, defect)

Description

[(not reading bugmail) Nick Desaulniers [:\n]]

In FxOS 2.0+ there will be the ability to have custom homescreens.  I'm working on one now.  Unfortunately, sampling fails with "this operation is insecure" message, probably because the src's of the images all begin with app:// (for packaged apps).  Can we allow app:// url's to be sampled from within WebGL?

Now that I think about it, it's going to be tough to sample icons for hosted apps, since they are cross domain.  Any way we can enable developers to create 3D home screens for Firefox OS?

Comment 1

[Sid Stamm [:geekboy or :sstamm]]

I'm not very familiar with sampling, and there are lots of places that cause that or a similar error[0] so I'm probably not gonna be very helpful... what exactly is the operation and in what context?  Are you trying to read bytes from a canvas via content script?

[0] http://mxr.mozilla.org/mozilla-central/ident?i=NS_ERROR_DOM_SECURITY_ERR

Comment 2

[Kelsey Gilbert [:jgilbert]]

(In reply to Nick Desaulniers [:\n] from comment #0)
> In FxOS 2.0+ there will be the ability to have custom homescreens.  I'm
> working on one now.  Unfortunately, sampling fails with "this operation is
> insecure" message, probably because the src's of the images all begin with
> app:// (for packaged apps).  Can we allow app:// url's to be sampled from
> within WebGL?
We can't allow them in general, but this should be allowed for privileged content. If homescreens aren't privileged content, then basically we can't support this operation.
> 
> Now that I think about it, it's going to be tough to sample icons for hosted
> apps, since they are cross domain.  Any way we can enable developers to
> create 3D home screens for Firefox OS?
CSS 3D transforms can operate on tainted data.

Comment 3

[(not reading bugmail) Nick Desaulniers [:\n]]

Actually, Harald Kirschner :digitarald, pointed out to me that I should be able to load the images as blobs using systemXHR in FxOS.  I don't believe that blobs are subject to origin policies.