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Diffstat (limited to 'docs/specs/WL_bind_wayland_display.spec')
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diff --git a/docs/specs/WL_bind_wayland_display.spec b/docs/specs/WL_bind_wayland_display.spec new file mode 100644 index 0000000..02bd6ea --- /dev/null +++ b/docs/specs/WL_bind_wayland_display.spec @@ -0,0 +1,175 @@ +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 1, March 1, 2011 + +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_buffer *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 + + +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. + + 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. + +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) |