angle/extensions/EGL_ANGLE_platform_angle_d3d.txt

Name

    ANGLE_platform_angle_d3d

Name Strings

    EGL_ANGLE_platform_angle_d3d

Contributors

    Shannon Woods, Google
    Geoff Lang, Google

Contacts

    Geoff Lang, Google (geofflang 'at' chromium 'dot' org)

Status

    Draft

Version

    Version 3, 2014-11-26

Number

    EGL Extension XXX

Extension Type

    EGL client extension

Dependencies

    Requires ANGLE_platform_angle.

Overview

    This extension enables selection of D3D display types.

New Types

    None

New Procedures and Functions

    None

New Tokens

    Accepted as values for the EGL_PLATFORM_ANGLE_TYPE_ANGLE attribute:

        EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE                 0x3207
        EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE                0x3208

    Accepted as an attribute name in the <attrib_list> argument of
    eglGetPlatformDisplayEXT:

        EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE               0x3209
        EGL_PLATFORM_ANGLE_ENABLE_AUTOMATIC_TRIM_ANGLE     0x320F

    Accepted as values for the EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE attribute:

        EGL_PLATFORM_ANGLE_DEVICE_TYPE_D3D_WARP_ANGLE      0x320B
        EGL_PLATFORM_ANGLE_DEVICE_TYPE_D3D_REFERENCE_ANGLE 0x320C

Additions to the EGL Specification

    None.

New Behavior

    To request a display that is backed by Direct3D resources, the value of
    EGL_PLATFORM_ANGLE_TYPE_ANGLE should be:
      - EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE for a D3D9 display,
      - EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE for a D3D11 display.

    To request a specific maximum feature level to be used by the D3D11
    display, EGL_PLATFORM_ANGLE_MAX_VERSION_MAJOR_ANGLE and
    EGL_PLATFORM_ANGLE_MAX_VERSION_MINOR_ANGLE can be used.  Only feature
    levels that are capable of supporting all available client APIs will be
    used unless explicitly requested.
    EGL_PLATFORM_ANGLE_MAX_VERSION_MAJOR_ANGLE and
    EGL_PLATFORM_ANGLE_MAX_VERSION_MINOR_ANGLE have no effect when requesting
    a D3D9 display.

    If no <attrib_list> is specified to eglGetPlatformDisplayEXT, the value of
    EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE is implicitly set to
    EGL_PLATFORM_ANGLE_DEVICE_TYPE_HARDWARE_ANGLE. Otherwise, the value of
    EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE should be:
      - EGL_PLATFORM_ANGLE_DEVICE_TYPE_HARDWARE_ANGLE to request a hardware
        accelerated device.
      - EGL_PLATFORM_ANGLE_DEVICE_TYPE_NULL_ANGLE to request a no-op driver
        for testing.
      - EGL_PLATFORM_ANGLE_DEVICE_TYPE_D3D_WARP_ANGLE to request an
        optimized software rasterizer.
      - EGL_PLATFORM_ANGLE_DEVICE_TYPE_D3D_REFERENCE_ANGLE to request a
        reference rasterizer.

    If EGL_PLATFORM_ANGLE_TYPE_ANGLE is set to
    EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE, the display can automatically respond
    to trim events from the operating system.  If the attribute
    EGL_PLATFORM_ANGLE_ENABLE_AUTOMATIC_TRIM_ANGLE is unspecified, it is
    implicitly set to EGL_FALSE.  Otherwise, the value of
    EGL_PLATFORM_ANGLE_ENABLE_AUTOMATIC_TRIM_ANGLE should be EGL_TRUE or
    EGL_FALSE.

    If EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE is set to
    EGL_PLATFORM_ANGLE_DEVICE_TYPE_WARP_ANGLE and EGL_PLATFORM_ANGLE_TYPE_ANGLE
    is not set to EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE, an EGL_BAD_ATTRIBUTE
    error is generated and EGL_NO_DISPLAY is returned.

    If EGL_PLATFORM_ANGLE_ENABLE_AUTOMATIC_TRIM_ANGLE is specified when
    EGL_PLATFORM_ANGLE_TYPE_ANGLE is not EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE
    or a value other than EGL_TRUE or EGL_FALSE is used, an EGL_BAD_ATTRIBUTE
    error is generated and EGL_NO_DISPLAY is returned.

Issues

    1) Some multithreaded applications can crash if the display automatically
       responds to trim events while the application is rendering from another
       thread.

       RESOLVED: Added an EGL_PLATFORM_ANGLE_ENABLE_AUTOMATIC_TRIM_ANGLE
       enum to specify if the display should respond to trim events.
       Applications that do multithreaded rendering should disable automatic
       trim and handle the trim events on their own.

Revision History

    Version 1, 2014-06-05 (Geoff Lang)
      - Initial draft
    Version 2, 2014-10-27 (Geoff Lang)
      - Separate WARP devices into a new attribute instead of a platform type.
      - Moved descriptions of platforms and major/minor versions from
        EGL_ANGLE_platform_angle spec to EGL_ANGLE_platform_angle_d3d.
    Version 3, 2014-11-26 (Geoff Lang)
      - Remove the USE_WARP bool and replace it with a DEVICE_TYPE enum.
    Version 4, 2015-03-11 (Geoff Lang)
      - Add the ENABLE_AUTOMATIC_TRIM enum.