Source/ThirdParty/ANGLE/extensions/EGL_ANGLE_direct_composition.txt

Name

    ANGLE_direct_composition

Name Strings

    EGL_ANGLE_direct_composition

Contributors

    John Bauman

Contacts

    John Bauman (jbauman 'at' google.com)

Status

    Draft

Version

    Version 2, Dec 14, 2015

Number

    EGL Extension #??

Dependencies

    This extension is written against the wording of the EGL 1.5 Specification.

Overview

    This extension allows specifying that the contents of a window surface be
    posted to the screen using the DirectComposition API.

New Types

    None

New Procedures and Functions

    None

New Tokens

    Accepted by the <attribute> parameter of eglQuerySurface and by the
    <attrib_list> parameter of eglCreateWindowSurface and
    eglCreatePlatformWindowSurface

    EGL_DIRECT_COMPOSITION_ANGLE                         0x33A5

Changes to Chapter 3 of the EGL 1.5 Specification (EGL Functions and Errors)

    Modify the fourth paragraph of Section 3.5.1, page 32
    (Creating On-Screen rendering Surfaces)

    "<attrib_list> specifies a list of attributes for the window. The list has
    the same structure as described for eglChooseConfig. Attributes that can
    be specified in <attrib_list> include EGL_DIRECT_COMPOSITION_ANGLE,
    EGL_GL_COLORSPACE, EGL_RENDER_BUFFER, EGL_VG_COLORSPACE, and
    EGL_VG_ALPHA_FORMAT."

    Add the following between paragraphs 6 and 7 of Section 3.5.1, page 32
    (Creating On-Screen Rendering Surfaces)

    "EGL_DIRECT_COMPOSITION_ANGLE specifies whether the surface will be posted
    to the window using DirectComposition. The default is EGL_FALSE. If
    EGL_TRUE is specified, <native_window> must be owned by the current
    process, and contents drawn by native APIs or EGLSurfaces with
    EGL_DIRECT_COMPOSITION_ANGLE as EGL_FALSE will appear underneath the
    contents of this surface."


    Add the following entry to Table 3.5, page 44 (Queryable surface
    attributes and types)

    Attribute                    Type    Description
    ---------------------------- ------- --------------------------------------
    EGL_DIRECT_COMPOSITION_ANGLE boolean Surface will be posted to the window
                                         using DirectComposition

Issues
    1. Should a surface attrib or config be used to specify that
    DirectComposition is needed.

    PROPOSED: A surface attrib would work and avoids creating
    otherwise-duplicate configs.

Revision History

    Version 2, 2015/12/14
      - Use attrib instead of config.

    Version 1, 2015/12/10
      - Initial draft.