Hm, where did you get that from? I don't see anything optional about the share_context param of the eglCreateContext() call in EGL spec.
Certainly I don't see anything in the spec that allowed for eglCreateContext() with share_context!=EGL_NO_CONTEXT to return a new context with no error, but subsequent eglMakeCurrent() on that context to fail with BAD_MATCH. The resources argument does not make much sense either - at least not in my case if you take into account that a procedure that is identical except that it does *NOT* attempt to share resources runs just fine, with no errors (but is slow obviously as it has to re-upload all the resources that should have been shared). On Fri, Aug 3, 2012 at 3:41 PM, RichardC <[email protected]> wrote: > Just a comment on "buggy" drivers. The EGL spec does not REQUIRE a driver > to support any form of context sharing. It does ALLOW a driver to support > context sharing if it has the resources (both hardware and software) to do > so. The driver is REQUIRED to return specific error codes if fails to do > what was requested. > > The implications of this are: > > that a driver may choose not to allow context sharing at all. If the > correct errors are returned, the driver is a conforming implementation. > on a particular device, calls to share contexts may succeed or fail > depending on the resources that have already been consumed by other > programs. > > > > On Friday, August 3, 2012 1:49:52 PM UTC+1, Latimerius wrote: >> >> On Fri, Aug 3, 2012 at 12:38 AM, Romain Guy <[email protected]> wrote: >> >> Well, keep in mind that you can't issue GL calls from a thread >> >> different than the rendering thread (well unless you play games with >> >> multiple EGL contexts sharing resources which doesn't even seem to >> >> work on the incomplete/buggy EGL implementation on Android). >> > >> > It works, WebView is (or used to) rely on this feature. You might be >> > running into a driver specific bug though. >> >> That's definitely good to hear, although very few people seem to know >> how to achieve it. I asked about it a few weeks ago, with no reply: >> >> >> https://groups.google.com/forum/?fromgroups#!searchin/android-developers/egl/android-developers/BHH08ak8MRA/mXaHFPNKMl8J >> >> It came up again a couple of days ago on android-ndk in this thread: >> >> >> https://groups.google.com/forum/?fromgroups#!searchin/android-ndk/egl/android-ndk/V3VpH65tpqA/blOrbldg7j0J >> >> The consensus seems to be it doesn't work. Note also a link there to >> a Mozilla dev blog post, he also comes to the conclusion context >> sharing doesn't work on Android. >> >> As far as a buggy driver goes - could be. One thing I know is that >> the failing behaviour was consistent across a bunch of Adreno >> 200/SGX540 devices with Android 2.1 or 2.2. I'm not sure anymore if I >> specifically tested it on Xoom/Honeycomb but if I did, it did not work >> there either. >> >> Is there a specific incantation to make it work? From my reading of >> the EGL spec, it should be as simple as passing the existing context >> to eglMakeContext() as the shared context argument... >> >> Thanks! -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
