| Name |
| |
| WL_bind_wayland_display |
| |
| Name Strings |
| |
| EGL_WL_bind_wayland_display |
| |
| Contact |
| |
| Kristian Høgsberg <krh@bitplanet.net> |
| Benjamin Franzke <benjaminfranzke@googlemail.com> |
| |
| Status |
| |
| Proposal |
| |
| Version |
| |
| Version 5, July 16, 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 entry points for binding and unbinding the |
| wl_display of a Wayland compositor to an EGLDisplay. Binding a |
| wl_display means that the EGL implementation should provide one or |
| more interfaces in the Wayland protocol to allow clients to create |
| wl_buffer objects. On the server side, this extension also |
| provides a new target for eglCreateImageKHR, to create an EGLImage |
| from a wl_buffer |
| |
| Adding an implementation specific wayland interface, allows the |
| EGL implementation to define specific wayland requests and events, |
| needed for buffer sharing in an EGL wayland platform. |
| |
| IP Status |
| |
| Open-source; freely implementable. |
| |
| New Procedures and Functions |
| |
| EGLBoolean eglBindWaylandDisplayWL(EGLDisplay dpy, |
| struct wl_display *display); |
| |
| EGLBoolean eglUnbindWaylandDisplayWL(EGLDisplay dpy, |
| struct wl_display *display); |
| |
| EGLBoolean eglQueryWaylandBufferWL(EGLDisplay dpy, |
| struct wl_resource *buffer, |
| EGLint attribute, EGLint *value); |
| |
| New Tokens |
| |
| Accepted as <target> in eglCreateImageKHR |
| |
| EGL_WAYLAND_BUFFER_WL 0x31D5 |
| |
| Accepted in the <attrib_list> parameter of eglCreateImageKHR: |
| |
| EGL_WAYLAND_PLANE_WL 0x31D6 |
| |
| Possible values for EGL_TEXTURE_FORMAT: |
| |
| EGL_TEXTURE_Y_U_V_WL 0x31D7 |
| EGL_TEXTURE_Y_UV_WL 0x31D8 |
| EGL_TEXTURE_Y_XUXV_WL 0x31D9 |
| EGL_TEXTURE_EXTERNAL_WL 0x31DA |
| |
| Accepted in the <attribute> parameter of eglQueryWaylandBufferWL: |
| |
| EGL_TEXTURE_FORMAT 0x3080 |
| EGL_WAYLAND_Y_INVERTED_WL 0x31DB |
| |
| |
| Additions to the EGL 1.4 Specification: |
| |
| To bind a server side wl_display to an EGLDisplay, call |
| |
| EGLBoolean eglBindWaylandDisplayWL(EGLDisplay dpy, |
| struct wl_display *display); |
| |
| To unbind a server side wl_display from an EGLDisplay, call |
| |
| EGLBoolean eglUnbindWaylandDisplayWL(EGLDisplay dpy, |
| struct wl_display *display); |
| |
| eglBindWaylandDisplayWL returns EGL_FALSE when there is already a |
| wl_display bound to EGLDisplay otherwise EGL_TRUE. |
| |
| eglUnbindWaylandDisplayWL returns EGL_FALSE when there is no |
| wl_display bound to the EGLDisplay currently otherwise EGL_TRUE. |
| |
| A wl_buffer can have several planes, typically in case of planar |
| YUV formats. Depending on the exact YUV format in use, the |
| compositor will have to create one or more EGLImages for the |
| various planes. The eglQueryWaylandBufferWL function should be |
| used to first query the wl_buffer texture format using |
| EGL_TEXTURE_FORMAT as the attribute. If the wl_buffer object is |
| not an EGL wl_buffer (wl_shm and other wayland extensions can |
| create wl_buffer objects of different types), this query will |
| return EGL_FALSE. In that case the wl_buffer can not be used with |
| EGL and the compositor should have another way to get the buffer |
| contents. |
| |
| If eglQueryWaylandBufferWL succeeds, the returned value will be |
| one of EGL_TEXTURE_RGB, EGL_TEXTURE_RGBA, EGL_TEXTURE_Y_U_V_WL, |
| EGL_TEXTURE_Y_UV_WL, EGL_TEXTURE_Y_XUXV_WL. The value returned |
| describes how many EGLImages must be used, which components will |
| be sampled from each EGLImage and how they map to rgba components |
| in the shader. The naming conventions separates planes by _ and |
| within each plane, the order or R, G, B, A, Y, U, and V indicates |
| how those components map to the rgba value returned by the |
| sampler. X indicates that the corresponding component in the rgba |
| value isn't used. |
| |
| RGB and RGBA buffer types: |
| |
| EGL_TEXTURE_RGB |
| One plane, samples RGB from the texture to rgb in the |
| shader. Alpha channel is not valid. |
| |
| EGL_TEXTURE_RGBA |
| One plane, samples RGBA from the texture to rgba in the |
| shader. |
| |
| YUV buffer types: |
| |
| EGL_TEXTURE_Y_U_V_WL |
| Three planes, samples Y from the first plane to r in |
| the shader, U from the second plane to r, and V from |
| the third plane to r. |
| |
| EGL_TEXTURE_Y_UV_WL |
| Two planes, samples Y from the first plane to r in |
| the shader, U and V from the second plane to rg. |
| |
| EGL_TEXTURE_Y_XUXV_WL |
| Two planes, samples Y from the first plane to r in |
| the shader, U and V from the second plane to g and a. |
| |
| EGL_TEXTURE_EXTERNAL_WL |
| Treated as a single plane texture, but sampled with |
| samplerExternalOES according to OES_EGL_image_external |
| |
| After querying the wl_buffer layout, create EGLImages for the |
| planes by calling eglCreateImageKHR with wl_buffer as |
| EGLClientBuffer, EGL_WAYLAND_BUFFER_WL as the target, NULL |
| context. If no attributes are given, an EGLImage will be created |
| for the first plane. For multi-planar buffers, specify the plane |
| to create the EGLImage for by using the EGL_WAYLAND_PLANE_WL |
| attribute. The value of the attribute is the index of the plane, |
| as defined by the buffer format. Writing to an EGLImage created |
| from a wl_buffer in any way (such as glTexImage2D, binding the |
| EGLImage as a renderbuffer etc) will result in undefined behavior. |
| |
| Further, eglQueryWaylandBufferWL accepts attributes EGL_WIDTH and |
| EGL_HEIGHT to query the width and height of the wl_buffer. |
| |
| Also, eglQueryWaylandBufferWL may accept |
| EGL_WAYLAND_Y_INVERTED_WL attribute to query orientation of |
| wl_buffer. If EGL_WAYLAND_Y_INVERTED_WL is supported |
| eglQueryWaylandBufferWL returns EGL_TRUE and value is a boolean |
| that tells if wl_buffer is y-inverted or not. If |
| EGL_WAYLAND_Y_INVERTED_WL is not supported |
| eglQueryWaylandBufferWL returns EGL_FALSE, in that case |
| wl_buffer should be treated as if value of |
| EGL_WAYLAND_Y_INVERTED_WL was EGL_TRUE. |
| |
| Issues |
| |
| Revision History |
| |
| Version 1, March 1, 2011 |
| Initial draft (Benjamin Franzke) |
| Version 2, July 5, 2012 |
| Add EGL_WAYLAND_PLANE_WL attribute to allow creating an EGLImage |
| for different planes of planar buffer. (Kristian Høgsberg) |
| Version 3, July 10, 2012 |
| Add eglQueryWaylandBufferWL and the various buffer |
| formats. (Kristian Høgsberg) |
| Version 4, July 19, 2012 |
| Use EGL_TEXTURE_FORMAT, EGL_TEXTURE_RGB, and EGL_TEXTURE_RGBA, |
| and just define the new YUV texture formats. Add support for |
| EGL_WIDTH and EGL_HEIGHT in the query attributes (Kristian Høgsberg) |
| Version 5, July 16, 2013 |
| Change eglQueryWaylandBufferWL to take a resource pointer to the |
| buffer instead of a pointer to a struct wl_buffer, as the latter has |
| been deprecated. (Ander Conselvan de Oliveira) |
| Version 6, September 16, 2013 |
| Add EGL_WAYLAND_Y_INVERTED_WL attribute to allow specifying |
| wl_buffer's orientation. |