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Rev	Author	Line No.	Line
5564	serge	1	Name
		2
		3	WL_create_wayland_buffer_from_image
		4
		5	Name Strings
		6
		7	EGL_WL_create_wayland_buffer_from_image
		8
		9	Contributors
		10
		11	Neil Roberts
		12	Axel Davy
		13	Daniel Stone
		14
		15	Contact
		16
		17	Neil Roberts
		18
		19	Status
		20
		21	Proposal
		22
		23	Version
		24
		25	Version 2, October 25, 2013
		26
		27	Number
		28
		29	EGL Extension #not assigned
		30
		31	Dependencies
		32
		33	Requires EGL 1.4 or later. This extension is written against the
		34	wording of the EGL 1.4 specification.
		35
		36	EGL_KHR_base_image is required.
		37
		38	Overview
		39
		40	This extension provides an entry point to create a wl_buffer which shares
		41	its contents with a given EGLImage. The expected use case for this is in a
		42	nested Wayland compositor which is using subsurfaces to present buffers
		43	from its clients. Using this extension it can attach the client buffers
		44	directly to the subsurface without having to blit the contents into an
		45	intermediate buffer. The compositing can then be done in the parent
		46	compositor.
		47
		48	The nested compositor can create an EGLImage from a client buffer resource
		49	using the existing WL_bind_wayland_display extension. It should also be
		50	possible to create buffers using other types of images although there is
		51	no expected use case for that.
		52
		53	IP Status
		54
		55	Open-source; freely implementable.
		56
		57	New Procedures and Functions
		58
		59	struct wl_buffer *eglCreateWaylandBufferFromImageWL(EGLDisplay dpy,
		60	EGLImageKHR image);
		61
		62	New Tokens
		63
		64	None.
		65
		66	Additions to the EGL 1.4 Specification:
		67
		68	To create a client-side wl_buffer from an EGLImage call
		69
		70	struct wl_buffer *eglCreateWaylandBufferFromImageWL(EGLDisplay dpy,
		71	EGLImageKHR image);
		72
		73	The returned buffer will share the contents with the given EGLImage. Any
		74	updates to the image will also be updated in the wl_buffer. Typically the
		75	EGLImage will be generated in a nested Wayland compositor using a buffer
		76	resource from a client via the EGL_WL_bind_wayland_display extension.
		77
		78	If there was an error then the function will return NULL. In particular it
		79	will generate EGL_BAD_MATCH if the implementation is not able to represent
		80	the image as a wl_buffer. The possible reasons for this error are
		81	implementation-dependant but may include problems such as an unsupported
		82	format or tiling mode or that the buffer is in memory that is inaccessible
		83	to the GPU that the given EGLDisplay is using.
		84
		85	Issues
		86
		87	1) Under what circumstances can the EGL_BAD_MATCH error be generated? Does
		88	this include for example unsupported tiling modes?
		89
		90	RESOLVED: Yes, the EGL_BAD_MATCH error can be generated for any reason
		91	which prevents the implementation from representing the image as a
		92	wl_buffer. For example, these problems can be but are not limited to
		93	unsupported tiling modes, inaccessible memory or an unsupported pixel
		94	format.
		95
		96	Revision History
		97
		98	Version 1, September 6, 2013
		99	Initial draft (Neil Roberts)
		100	Version 2, October 25, 2013
		101	Added a note about more possible reasons for returning EGL_BAD_FORMAT.

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(root)/contrib/sdk/sources/Mesa/mesa-10.6.0/docs/specs/WL_create_wayland_buffer_from_image.spec – Rev 5564