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Name
ANGLE_iosurface_client_buffer
Name Strings
EGL_ANGLE_iosurface_client_buffer
Contributors
Corentin Wallez
Geoff Lang
James Darpinian
Le Hoang Quyen
Contacts
Corentin Wallez, Google Inc. (cwallez 'at' google.com)
Status
Draft
Version
Version 6, Aug 25, 2020
Number
EGL Extension #??
Dependencies
This extension is written against the wording of the EGL 1.4
Specification.
Overview
This extension allows creating EGL surfaces from IOSurface objects.
New Types
None
New Procedures and Functions
None
New Tokens
Accepted in the <buftype> parameter of eglCreatePbufferFromClientBuffer:
EGL_IOSURFACE_ANGLE 0x3454
EGL_IOSURFACE_PLANE_ANGLE 0x345A
EGL_TEXTURE_RECTANGLE_ANGLE 0x345B
EGL_TEXTURE_TYPE_ANGLE 0x345C
EGL_TEXTURE_INTERNAL_FORMAT_ANGLE 0x345D
EGL_IOSURFACE_USAGE_HINT_ANGLE 0x348A
Accepted in the <attribute> parameter of
eglGetConfigAttrib:
EGL_BIND_TO_TEXTURE_TARGET_ANGLE 0x348D
Additions to Chapter 3 of the EGL 1.4 Specification (EGL Functions and Errors)
Replace the last sentence of paragraph 1 of Section 3.5.3 with the
following text.
"Currently, the only client API resources which may be bound in this
fashion are OpenVG VGImage objects and IOSurface objects."
Replace the third paragraph of Section 3.5.3 with the following text.
"<buftype> specifies the type of buffer to be bound. The only allowed values
of <buftype> are EGL_OPENVG_IMAGE and EGL_IOSURFACE_ANGLE".
Append the following text to the fourth paragraph of Section 3.5.3.
"When <buftype> is EGL_IOSURFACE_ANGLE, <buffer> must be a valid IOSurface
object case into the type EGLClientBuffer."
Append to the end of Section 3.5.3.
"When <buftype> is EGL_IOSURFACE_ANGLE, <attrib_list> must contain all the
following attributes otherwise EGL_BAD_PARAMETER is generated. The
attributes must satisfy the following constraints otherwise
EGL_BAD_ATTRIBUTE is generated:
- EGL_TEXTURE_TYPE_ANGLE, and EGL_TEXTURE_INTERNAL_FORMAT_ANGLE followed
by OpenGL enums for texture types, and texture internal format
respectively.
- EGL_TEXTURE_FORMAT with a value of EGL_TEXTURE_RGBA
- EGL_WIDTH with a value between 1 and the width of <buffer>.
- EGL_HEIGHT with a value between 1 and the height of <buffer>.
- EGL_TEXTURE_TARGET with a value that matches the attribute
EGL_BIND_TO_TEXTURE_TARGET_ANGLE as queried from eglGetConfigAttrib.
- EGL_IOSURFACE_PLANE_ANGLE with a value between 0 and the number of
planes of <buffer> (exclusive).
In addition the EGL_TEXTURE_TYPE_ANGLE and
EGL_TEXTURE_INTERNAL_FORMAT_ANGLE attributes must be one of the
combinations listed in table egl.iosurface.formats or an
EGL_BAD_PARAMETER is generated. The combination must also be a valid
combinations for glTexImage2D or EGL_BAD_PARAMETER is generated.
The attribute EGL_IOSURFACE_USAGE_HINT_ANGLE may optionally be specified as
a combination of the bits EGL_IOSURFACE_READ_HINT_ANGLE and
EGL_IOSURFACE_WRITE_HINT_ANGLE. On the iOS Simulator platform, where
IOSurface support is incomplete, these hints indicate whether the intent is
to read from the IOSurface, write to it, or both. Explicitly passing 0 for
this attribute is equivalent to setting both the read and write usage
bits. This attribute is ignored on other platforms."
---------------------------------------------------------------------------
Texture Type Texture Internal Format
---------------------------------------------------------------------------
GL_UNSIGNED_BYTE GL_RED
GL_UNSIGNED_SHORT GL_RED
GL_UNSIGNED_SHORT GL_R16UI
GL_UNSIGNED_BYTE GL_RG
GL_UNSIGNED_SHORT GL_RG
GL_UNSIGNED_BYTE GL_RGB
GL_UNSIGNED_BYTE GL_RGBA
GL_UNSIGNED_BYTE GL_BGRA_EXT
GL_UNSIGNED_INT_2_10_10_10_REV GL_RGB10_A2
GL_HALF_FLOAT GL_RGBA
---------------------------------------------------------------------------
Table egl.iosurface.formats - Valid combinations of format, type and
internal format for IOSurface-backed pbuffers.
---------------------------------------------------------------------------
Append to the end of Section 3.5.3.
"When a pbuffer is created with type EGL_IOSURFACE_ANGLE, the contents
of the associcated IOSurface object are undefined while the pbuffer is
bound to a client texture."
Append to the end of Table 3.1.
---------------------------------------------------------------------------
Attribute Type Notes
---------------------------------------------------------------------------
EGL_BIND_TO_TEXTURE_TARGET_ANGLE enum Texture target supported by
IOSurface-backed pbuffers.
---------------------------------------------------------------------------
Issues
1. Can RGB formats be supported?
RESOLVED: Support for RGB internal formats is added in version 3. Surfaces
with an RGB format will ensure that the alpha channel of the IOSurface is
reset to 1.0 when it is used.
Revision History
Version 1, 2017/12/06 - first draft.
Version 2, 2019/04/01 - Allow MakeCurrent.
Version 3, 2019/08/13 - Allow RGB internal formats
Version 4, 2019/12/28 - Add usage hint; require TEXTURE_RECTANGLE on macOS
and TEXTURE_2D on iOS
Version 5, 2020/06/30 - Allow RGB10_A2 internal formats
Version 6, 2020/08/25 - Allow R16 and RG16 formats for P010 surfaces
Version 7, 2023/09/19 - Allow RGBA/RGBX surfaces
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