Attachment 113752 Details for Bug 67676 – version four

version four

EGL_MESA_transparent_alpha.txt (text/plain), 3.19 KB, created by Jonny Lamb on 2015-02-23 10:36:59 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Jonny Lamb

Created: 2015-02-23 10:36:59 UTC

Size: 3.19 KB

patch

obsolete

>Name
>
>    EGL_MESA_transparent_alpha
>
>Name Strings
>
>    EGL_MESA_transparent_alpha
>
>Contributors
>
>    Jonny Lamb <jonny.lamb@collabora.co.uk>
>
>Contacts
>
>    Jonny Lamb <jonny.lamb@collabora.co.uk>
>
>Status
>
>    Draft
>
>Version
>
>    Version 4, 2015-02-23
>
>Number
>
>    EGL Extension #XXX
>
>Extension Type
>
>    EGL display extension
>
>Dependencies
>
>    This extension is written against the wording of the 2014.08.17 revision
>    of the EGL 1.5 Specification.
>
>Overview
>
>    This extension defines how to create EGL window surfaces which respect
>    their alpha channels.
>
>    To obtain an EGL window surface with a meaningful alpha channel,
>    use an EGLConfig with EGL_TRANSPARENT_TYPE set to
>    EGL_TRANSPARENT_ALPHA_MESA.
>
>New Types
>
>    None
>
>New Procedures and Functions
>
>    None
>
>New Tokens
>
>    Accepted as the value of the EGLConfig attribute EGL_TRANSPARENT_TYPE:
>
>        EGL_TRANSPARENT_ALPHA_MESA                0xXXXX
>
>Additions to the EGL 1.5 Specification
>
>    In section 3.4 "Configuration Management", under the "Other EGLConfig
>    Attribute Descriptions" heading, append to the paragraph which begins with
>    "EGL_TRANSPARENT_TYPE indicates" and ends with "and
>    EGL_TRANSPARENT_BLUE_VALUE, respectively" the following:
>
>    "If the attribute is EGL_TRANSPARENT_ALPHA_MESA then window
>    surfaces created with the EGLConfig will have their alpha channel
>    respected with pre-multiplied alpha implied. Creating non-window
>    surfaces with the EGLConfig will generate an EGL_BAD_MATCH error."
>
>    In the next paragraph replace the first sentence with:
>
>    "If EGL_TRANSPARENT_TYPE is either EGL_NONE or
>    EGL_TRANSPARENT_ALPHA_MESA, then the values for
>    EGL_TRANSPARENT_RED_VALUE, EGL_TRANSPARENT_GREEN_VALUE, and
>    EGL_TRANSPARENT_BLUE_VALUE are undefined."
>
>    Before the paragraph which begins with "EGL_MAX_PBUFFER_WIDTH and
>    EGL_MAX_PBUFFER_HEIGHT indicate" insert the following paragraph:
>
>    "If EGL_TRANSPARENT_TYPE is EGL_TRANSPARENT_ALPHA_MESA and
>    EGL_ALPHA_SIZE is 0, window surfaces created with the EGLConfig
>    will be fully opaque, as if alpha were set to 1.0."
>
>Issues
>
>    1. Should non-window surfaces created with EGL_TRANSPARENT_TYPE
>       set to EGL_TRANSPARENT_ALPHA_MESA generate an error or have no
>       effect on the surface?
>
>       RESOLUTION: Attempting to create a non-window surface with a
>       config in which EGL_TRANSPARENT_TYPE is
>       EGL_TRANSPARENT_ALPHA_MESA then an EGL_BAD_MATCH error is
>       generated.
>
>Revision History
>
>    Version 4, 2015-02-23 (Jonny Lamb)
>        - Removed paragraph on how to determine whether the
>          EGL implementation supports the extension.
>        - Removed "New Behavior" section, moving its only paragraph
>          into "Overview".
>        - Reworded resolution to issue 1 and clarified which error is
>          generated.
>
>    Version 3, 2015-02-17 (Jonny Lamb)
>        - Added pre-multiplied alpha implication.
>
>    Version 2, 2015-02-16 (Jonny Lamb)
>        - Resolved issue #1 to "Yes".
>        - Changed extension type to "display extension" and removed
>          dependency on EGL_EXT_client_extensions.
>        - Added MESA suffix to the new token.
>
>    Version 1, 2014-12-15 (Jonny Lamb)
>        - Initial draft
>
># vim:ai:et:sw=4:ts=4:

Actions: View

Attachments on bug 67676: 93777 | 94274 | 111864 | 113529 | 113561 | 113563 | 113752 | 144608 | 144609 | 144610 | 144758

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.