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Name
EXT_device_enumeration
Name Strings
EGL_EXT_device_enumeration
Contributors
James Jones
Jamie Madill
Contacts
James Jones, NVIDIA (jajones 'at' nvidia.com)
Status
Complete.
Version
Version 1 - March 24th, 2015
Number
EGL Extension #88
Extension Type
EGL client extension
Dependencies
Written against the wording of EGL 1.5.
Requires EGL 1.5 or an earlier verison of EGL with the
EGL_EXT_client_extensions extension.
Requires the EGL_EXT_device_query extension.
Overview
Increasingly, EGL and its client APIs are being used in place of
"native" rendering APIs to implement the basic graphics
functionality of native windowing systems. This creates demand
for a method to initialize EGL displays and surfaces directly on
top of native GPU or device objects rather than native window
system objects. The mechanics of enumerating the underlying
native devices and constructing EGL displays and surfaces from
them have been solved in various platform and implementation-
specific ways. The EGL device family of extensions offers a
standardized framework for bootstrapping EGL without the use of
any underlying "native" APIs or functionality.
The original EGL_EXT_device_base extension combined the conceptually
separate operations of querying the underlying device used by a
given EGLDisplay and enumerating devices from scratch. It was later
identified that the former is useful even in EGL implementations
that have no need or ability to allow enumerating all the devices
available on a system. To accommodate this, the extension was
split in two.
New Types
None
New Functions
EGLBoolean eglQueryDevicesEXT(EGLint max_devices,
EGLDeviceEXT *devices,
EGLint *num_devices);
Add the following at the beginning of section "3.2 Devices"
"EGL devices can be enumerated before EGL is initialized. Use:
EGLBoolean eglQueryDevicesEXT(EGLint max_devices,
EGLDeviceEXT *devices,
EGLint *num_devices);
"to obtain a list of all supported devices in the system. On
success, EGL_TRUE is returned, and <num_devices> devices are
stored in the array pointed to by <devices>. <num_devices> will
be less than or equal to <max_devices>. If <devices> is NULL,
then <max_devices> will be ignored, no devices will be returned in
<devices>, and <num_devices> will be set to the number of
supported devices in the system. All implementations must support
at least one device.
"On failure, EGL_FALSE is returned. An EGL_BAD_PARAMETER error is
generated if <max_devices> is less than or equal to zero unless
<devices> is NULL, or if <num_devices> is NULL."
Remove the following paragraph from section "3.4 Display Attributes"
"Because the EGLDeviceEXT is a property of <dpy>, any use of an
associated EGLDeviceEXT after <dpy> has been terminated gives
undefined results. Querying an EGL_DEVICE_EXT from <dpy> after a
call to eglTerminate() (and subsequent re-initialization) may
return a different value."
Issues
None
Revision History:
#1 (March 24th, 2015) James Jones
- Initial branch from EGL_EXT_device_base version #8
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