docs/specs/EGL_MESA_platform_surfaceless.txt

   1 Name
   2
   3     MESA_platform_surfaceless
   4
   5 Name Strings
   6
   7     EGL_MESA_platform_surfaceless
   8
   9 Contributors
  10
  11     Chad Versace <chadversary@google.com>
  12     Haixia Shi <hshi@google.com>
  13     Stéphane Marchesin <marcheu@google.com>
  14     Zach Reizner <zachr@chromium.org>
  15     Gurchetan Singh <gurchetansingh@google.com>
  16
  17 Contacts
  18
  19     Chad Versace <chadversary@google.com>
  20
  21 Status
  22
  23     DRAFT
  24
  25 Version
  26
  27     Version 2, 2016-10-13
  28
  29 Number
  30
  31     EGL Extension #TODO
  32
  33 Extension Type
  34
  35     EGL client extension
  36
  37 Dependencies
  38
  39     Requires EGL 1.5 or later; or EGL 1.4 with EGL_EXT_platform_base.
  40
  41     This extension is written against the EGL 1.5 Specification (draft
  42     20140122).
  43
  44     This extension interacts with EGL_EXT_platform_base as follows. If the
  45     implementation supports EGL_EXT_platform_base, then text regarding
  46     eglGetPlatformDisplay applies also to eglGetPlatformDisplayEXT;
  47     eglCreatePlatformWindowSurface to eglCreatePlatformWindowSurfaceEXT; and
  48     eglCreatePlatformPixmapSurface to eglCreatePlatformPixmapSurfaceEXT.
  49
  50 Overview
  51
  52     This extension defines a new EGL platform, the "surfaceless" platform. This
  53     platfom's defining property is that it has no native surfaces, and hence
  54     neither eglCreatePlatformWindowSurface nor eglCreatePlatformPixmapSurface
  55     can be used. The platform is independent of any native window system.
  56
  57     The platform's intended use case is for enabling OpenGL and OpenGL ES
  58     applications on systems where no window system exists. However, the
  59     platform's permitted usage is not restricted to this case.  Since the
  60     platform is independent of any native window system, it may also be used on
  61     systems where a window system is present.
  62
  63 New Types
  64
  65     None
  66
  67 New Procedures and Functions
  68
  69     None
  70
  71 New Tokens
  72
  73     Accepted as the <platform> argument of eglGetPlatformDisplay:
  74
  75         EGL_PLATFORM_SURFACELESS_MESA           0x31DD
  76
  77 Additions to the EGL Specification
  78
  79     None.
  80
  81 New Behavior
  82
  83     To determine if the EGL implementation supports this extension, clients
  84     should query the EGL_EXTENSIONS string of EGL_NO_DISPLAY.
  85
  86     To obtain an EGLDisplay on the surfaceless platform, call
  87     eglGetPlatformDisplay with <platform> set to EGL_PLATFORM_SURFACELESS_MESA.
  88     The <native_display> parameter must be EGL_DEFAULT_DISPLAY.
  89
  90     eglCreatePlatformWindowSurface fails when called with a <display> that
  91     belongs to the surfaceless platform. It returns EGL_NO_SURFACE and
  92     generates EGL_BAD_NATIVE_WINDOW. The justification for this unconditional
  93     failure is that the surfaceless platform has no native windows, and
  94     therefore the <native_window> parameter is always invalid.
  95
  96     Likewise, eglCreatePlatformPixmapSurface also fails when called with a
  97     <display> that belongs to the surfaceless platform.  It returns
  98     EGL_NO_SURFACE and generates EGL_BAD_NATIVE_PIXMAP.
  99
 100     The surfaceless platform imposes no platform-specific restrictions on the
 101     creation of pbuffers, as eglCreatePbufferSurface has no native surface
 102     parameter.  Specifically, if the EGLDisplay advertises an EGLConfig whose
 103     EGL_SURFACE_TYPE attribute contains EGL_PBUFFER_BIT, then the EGLDisplay
 104     permits the creation of pbuffers with that config.
 105
 106 Issues
 107
 108     None.
 109
 110 Revision History
 111
 112     Version 2, 2016-10-13 (Chad Versace)
 113         - Assign enum values
 114         - Define interfactions with EGL 1.4 and EGL_EXT_platform_base.
 115         - Add Gurchetan as contributor, as he implemented the pbuffer support.
 116
 117     Version 1, 2016-09-23 (Chad Versace)
 118         - Initial version
 119         - Posted for review at
 120           https://lists.freedesktop.org/archives/mesa-dev/2016-September/129549.html