EGL_EXT_config_select_group

EGL_EXT_config_select_group

Hal Gentz <zegentzy@protonmail.com>
Adam Jackson <ajax@redhat.com>
Robert Mader <robert.mader@posteo.de>

Hal Gentz <zegentzy@protonmail.com>

Draft

Version 4, 2021-06-24

EGL Extension #145

EGL client extension

This extension is written against the wording of the 2014.08.27 revision
of the EGL 1.5 Specification.

This extension provides a mechanism to lower the config selection priority
of the configs returned by eglChooseConfig. A new config attribute is
introduced, providing a way for the implementation to group configs into
different config selection categories.  The config selection priorities of
all the configs in one category may be higher or lower than the ones in
other categories.  The config selection priorities in one category follow
the rules of eglChooseConfig. See also GLX_SGIX_visual_select_group.

None

None

Accepted as a new EGLConfig attribute:

    EGL_CONFIG_SELECT_GROUP_EXT                0x34C0

In section 3.4 "Configuration Management", under the "Buffer Descriptions
and Attributes" heading, append to table 3.1 the following:

"EGL_CONFIG_SELECT_GROUP_EXT | integer | the config select group"

In section 3.4 "Configuration Management", under the "Other EGLConfig
Attribute Descriptions" heading, append to the end the following:

"The attribute EGL_CONFIG_SELECT_GROUP_EXT is used to specify the config
selection category of the config. Configs in the i-th category have a higher
config selection priority than those found in the (i+1)-th category.

"The attribute EGL_CONFIG_SELECT_GROUP_EXT is used by the implementation to
override the default sorting rules, by collecting configurations into
groups. It is not accepted by the <attrib_list> parameter of
eglChooseConfig, but it is accepted as the <attribute> in
eglGetConfigAtrrib."

In section 3.4 "Configuration Management", under the "Sorting of EGLConfigs"
heading, append to table 3.4 the following:

"EGL_CONFIG_SELECT_GROUP_EXT | 0 | Ignore | Smaller | 0"

In section 3.4 "Configuration Management", under the "Sorting of EGLConfigs"
heading, append before the list entry which starts with "1. Special: by
EGL_CONFIG_CAVEAT" the following entry:

"0. Smaller EGL_CONFIG_SELECT_GROUP_EXT."

None

Version 4, 2021-06-24 (Robert Mader)
    - Moved to EXT, changed enum value to 0x34C0.

Version 3, 2020-04-06 (Robert Mader)
    - Changed enum value to 0x31DF, added contributors.

Version 2, 2019-07-11 (Hal Gentz)
    - Resolved issues pointed out by Adam Jackson.

Version 1, 2019-06-21 (Hal Gentz)
    - Initial draft