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+Name
+
+ WL_create_wayland_buffer_from_image
+
+Name Strings
+
+ EGL_WL_create_wayland_buffer_from_image
+
+Contributors
+
+ Neil Roberts
+ Axel Davy
+ Daniel Stone
+
+Contact
+
+ Neil Roberts <neil.s.roberts@intel.com>
+
+Status
+
+ Proposal
+
+Version
+
+ Version 2, October 25, 2013
+
+Number
+
+ EGL Extension #not assigned
+
+Dependencies
+
+ Requires EGL 1.4 or later. This extension is written against the
+ wording of the EGL 1.4 specification.
+
+ EGL_KHR_base_image is required.
+
+Overview
+
+ This extension provides an entry point to create a wl_buffer which shares
+ its contents with a given EGLImage. The expected use case for this is in a
+ nested Wayland compositor which is using subsurfaces to present buffers
+ from its clients. Using this extension it can attach the client buffers
+ directly to the subsurface without having to blit the contents into an
+ intermediate buffer. The compositing can then be done in the parent
+ compositor.
+
+ The nested compositor can create an EGLImage from a client buffer resource
+ using the existing WL_bind_wayland_display extension. It should also be
+ possible to create buffers using other types of images although there is
+ no expected use case for that.
+
+IP Status
+
+ Open-source; freely implementable.
+
+New Procedures and Functions
+
+ struct wl_buffer *eglCreateWaylandBufferFromImageWL(EGLDisplay dpy,
+ EGLImageKHR image);
+
+New Tokens
+
+ None.
+
+Additions to the EGL 1.4 Specification:
+
+ To create a client-side wl_buffer from an EGLImage call
+
+ struct wl_buffer *eglCreateWaylandBufferFromImageWL(EGLDisplay dpy,
+ EGLImageKHR image);
+
+ The returned buffer will share the contents with the given EGLImage. Any
+ updates to the image will also be updated in the wl_buffer. Typically the
+ EGLImage will be generated in a nested Wayland compositor using a buffer
+ resource from a client via the EGL_WL_bind_wayland_display extension.
+
+ If there was an error then the function will return NULL. In particular it
+ will generate EGL_BAD_MATCH if the implementation is not able to represent
+ the image as a wl_buffer. The possible reasons for this error are
+ implementation-dependant but may include problems such as an unsupported
+ format or tiling mode or that the buffer is in memory that is inaccessible
+ to the GPU that the given EGLDisplay is using.
+
+Issues
+
+ 1) Under what circumstances can the EGL_BAD_MATCH error be generated? Does
+ this include for example unsupported tiling modes?
+
+ RESOLVED: Yes, the EGL_BAD_MATCH error can be generated for any reason
+ which prevents the implementation from representing the image as a
+ wl_buffer. For example, these problems can be but are not limited to
+ unsupported tiling modes, inaccessible memory or an unsupported pixel
+ format.
+
+Revision History
+
+ Version 1, September 6, 2013
+ Initial draft (Neil Roberts)
+ Version 2, October 25, 2013
+ Added a note about more possible reasons for returning EGL_BAD_FORMAT.