extensions/EGL_ANGLE_timestamp_surface_attribute.txt

Name

    ANGLE_timestamp_surface_attribute

Name Strings

    EGL_ANGLE_timestamp_surface_attribute

Contributors

    Mohan Maiya
    Ian Elliot

Contacts

    Mohan Maiya, Samsung (m.maiya 'at' samsung 'dot' com)

Notice

    Copyright (c) 2022 The Khronos Group Inc. Copyright terms at
        http://www.khronos.org/registry/speccopyright.html

Status

    Draft.

Version

    Version 1, July 12, 2022

Number

    EGL Extension ###

Dependencies

    Requires support for EGL_ANDROID_get_frame_timestamps extension.
    Refer to EGL_ANDROID_get_frame_timestamps specification for other
    dependencies.

Overview

    On Android most of the functionality required by EGL_ANDROID_get_frame_timestamps
    is handled by a wrapper outside of the EGL driver. However it is necessary
    to be aware of EGL_TIMESTAMPS_ANDROID state on some drivers
    (like ANGLE, which layers GLES APIs over Vulkan, which needs this information
    to setup Vulkan swapchains appropriately).

    This extension allows ANGLE's EGL implementation to rely on the Android EGL
    loader to support and implement the EGL_ANDROID_get_frame_timestamps extension,
    with the exception that ANGLE's EGL implementation will support caching
    EGL_TIMESTAMPS_ANDROID state.

    For details about EGL_TIMESTAMPS_ANDROID and other timestamp related terminology
    please refer to the EGL_ANDROID_get_frame_timestamps specification.


New Types

    None.

New Procedures and Functions

    None.

New Tokens

    None.

For clarity, restating the section of EGL_ANDROID_get_frame_timestamps specification
that will be supported by this extension:

Add to the list of supported tokens for eglSurfaceAttrib in section 3.5.6
"Surface Attributes", page 43:

    If attribute is EGL_TIMESTAMPS_ANDROID, then values specifies whether to
    enable/disable timestamp collection for this surface. A value of EGL_TRUE
    enables timestamp collection, while a value of EGL_FALSE disables it. The
    initial value is false. If surface is not a window surface this has no
    effect.

Issues

    None.

Revision History

    #2 - (August 23, 2022) Mohan Maiya
         Added language to clarify that the extension will require support,
         from an external module, of the EGL_ANDROID_get_frame_timestamps
         extension for the most part with the exception of providing support
         for caching EGL_TIMESTAMPS_ANDROID state.

    #1 - (July 12, 2022) Mohan Maiya
         Original draft