extensions/EGL_ANGLE_robust_resource_initialization.txt

Name

    ANGLE_robust_resource_initialization

Name Strings

    EGL_ANGLE_robust_resource_initialization

Contributors

    Geoff Lang, Google
    Ken Russell, Google

Contacts

    Shannon Woods, Google (shannonwoods 'at' google.com)

Status

    Draft

Version

    Version 4, September 19, 2017

Number

    EGL Extension TBD

Dependencies

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

    An OpenGL ES implementation supporting ANGLE_robust_resource_initialization
    or an implementation supporting equivalent functionality is required.

Overview

    This extension allows creating an OpenGL ES context or EGL surface
    supporting robust resource initialization.

New Types

    None

New Procedures and Functions

    None

New Tokens

    Accepted as an attribute name by eglCreateContext, eglQueryContext,
    eglCreateWindowSurface, eglCreatePbufferSurface, eglCreatePixmapSurface,
    and eglQuerySurface:

        EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE    0x3453

Additions to the EGL 1.5 Specification

    Add a new section entitled "OpenGL ES Robust Resource Initialization"
    to section 3.7.1:

    "If the attribute EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE
    is set to EGL_TRUE, a context supporting <robust resource initialization>
    will be created. OpenGL ES contexts must support the
    ANGLE_robust_resource_initialization extension, or equivalent core API
    functionality. This attribute is supported only for OpenGL ES contexts.
    The default value of EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE
    is EGL_FALSE."

    Add a new paragraph to section 3.7.4 "Context Queries" under
    eglQueryContext:

    "Querying EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE returns if
    the context was created using robust initialization."

    Add a new paragrah to section 3.5.1 "Creating On-Screen Rendering
    Surfaces" and section 3.5.2 "Creating Off-Screen Rendering Surfaces":

    "EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE specifies if the pixel values of
    the surface are initialized.  If its value is EGL_TRUE then all pixel and
    stencil values in the surface are initialized to zero, depth values are
    initialized to 1.0. Otherwise the contents are undefined. The default value
    of EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is EGL_FALSE."

    Add a new paragrah to section 3.5.6 "Surface Attributes" under
    eglQuerySurface:

    "Querying EGL_CONTEXT_ROBUST_RESOURCE_INITIALIZATION_ANGLE returns if
    the surface was created using robust initialization."

    Modify the 2nd paragraph of section 3.10.1 "Posting to a Window":

    "... If EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is EGL_TRUE, following
    conditions apply. If EGL_SWAP_BEHAVIOR attribute is not
    EGL_BUFFER_PRESERVED, color and stencil buffer values are set to zero, depth
    buffer values are set to 1.0. Otherwise, color and ancillary buffer values
    preserved.

    If EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is EGL_FALSE, the contents of
    ancillary buffers are always undefined after calling eglSwapBuffers. ...
    "

Issues

    (1) Should this be a Display or Context creation extension?

    RESOLVED (3): Making this a Context creation extension has complications in
    the implementation - what happens to resources shared between Contexts
    with and without the extension enabled? Also for display-created resources,
    such as those used in the D3D11 SwapChain, there's no way to specify if
    we want them robustly initialized. Hence it is clearer to specify this
    extension as a Display extension.

    RESOLVED (4): This extension has been moved back to a context/surface
    creation attribute. This makes the extension much easier to detect before
    the GL context is created.

Revision History

    Version 1, 2015/01/07 - first draft.
    Version 2, 2017/03/01 - renamed extension and enum.
    Version 3, 2017/05/31 - renamed extension and made into display extension.
    Version 4, 2017/09/19 - renamed extension and changed into a
                            context/surface creation attribute.
    Version 5, 2024/09/21 - specified that depth values are initialized to 1.0
                            specified that stencil values are initialized to 0.0