Name

    ANGLE_platform_angle_vulkan_device_uuid

Name Strings

    EGL_ANGLE_platform_angle_vulkan_device_uuid

Contributors

    Steven Noonan

Contacts

    Steven Noonan <steven@uplinklabs.net>

Status

    Draft

Version

    Version 1, 2024-12-13

Number

    EGL Extension XXX

Extension Type

    EGL client extension

Dependencies

    This extension requires EGL 1.5 and the ANGLE_platform_angle_vulkan
    extension.

Overview

    This extension enables developers to specify additional selection criteria
    when creating an ANGLE Vulkan context, ensuring that the context is
    associated with a particular physical device and driver combination,
    providing more precise control over device selection.

New Types

    None

New Procedures and Functions

    None

New Tokens

    Accepted as an attribute name in the <attrib_list> argument of
    eglGetPlatformDisplay:

        EGL_PLATFORM_ANGLE_VULKAN_DEVICE_UUID_ANGLE    0x34F0
        EGL_PLATFORM_ANGLE_VULKAN_DRIVER_UUID_ANGLE    0x34F1
        EGL_PLATFORM_ANGLE_VULKAN_DRIVER_ID_ANGLE      0x34F2

Additions to the EGL Specification

    None

New Behavior

    The EGL_PLATFORM_ANGLE_VULKAN_DEVICE_UUID attribute may be passed to
    eglGetPlatformDisplay to specify the device UUID of the desired Vulkan
    device for the ANGLE context. The EGL_PLATFORM_ANGLE_VULKAN_DRIVER_ID
    attribute may be passed to select a device by its driver's VkDriverId
    value.

    Attributes introduced by this extension must be used in conjunction with
    the EGL_PLATFORM_ANGLE_TYPE_ANGLE attribute set to
    EGL_PLATFORM_ANGLE_TYPE_VULKAN_ANGLE. If it is not, eglGetPlatformDisplay
    will generate an EGL_BAD_ATTRIBUTE error and return EGL_NO_DISPLAY.

    The value provided for EGL_PLATFORM_ANGLE_VULKAN_DEVICE_UUID must be
    a valid pointer to a 16-byte Vulkan device UUID, or a NULL pointer
    indicating that any device is acceptable. The UUID value should match the
    deviceUUID field of VkPhysicalDeviceIDProperties for a VkPhysicalDevice in
    the system.

    The value provided for EGL_PLATFORM_ANGLE_VULKAN_DRIVER_UUID must be
    a valid pointer to a 16-byte Vulkan driver UUID, or a NULL pointer
    indicating that any driver is acceptable. The UUID value should match the
    driverUUID field of VkPhysicalDeviceIDProperties for a VkPhysicalDevice in
    the system.

    The value provided for EGL_PLATFORM_ANGLE_VULKAN_DRIVER_ID must be
    a VkDriverId value corresponding to the driverID field of the
    VkPhysicalDeviceDriverProperties structure for a device in the system.

    If no VkPhysicalDevice is found matching all of the provided search
    criteria, the implementation may fall back to any other available
    VkPhysicalDevice.

Usage Example

    // Illustrates using all of the attributes at once
    uint8_t deviceUUID[16] = { /* UUID value */ };
    uint8_t driverUUID[16] = { /* UUID value */ };
    VkDriverId driverId = VK_DRIVER_ID_MESA_HONEYKRISP;

    EGLAttrib attribs[] = {
        EGL_PLATFORM_ANGLE_TYPE_ANGLE, EGL_PLATFORM_ANGLE_TYPE_VULKAN_ANGLE,
        EGL_PLATFORM_ANGLE_VULKAN_DEVICE_UUID_ANGLE, (EGLAttrib)deviceUUID,
        EGL_PLATFORM_ANGLE_VULKAN_DRIVER_UUID_ANGLE, (EGLAttrib)driverUUID,
        EGL_PLATFORM_ANGLE_VULKAN_DRIVER_ID_ANGLE, (EGLAttrib)driverId,
        EGL_NONE
    };

    EGLDisplay display =
        eglGetPlatformDisplay(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, attribs);

    if (display == EGL_NO_DISPLAY) {
        // Handle display creation failure
    }

Issues

    1) Why provide support for specifying all three of device UUID, driver
       UUID, and driver ID?

       RESOLVED: The goal is to uniquely identify a specific VkPhysicalDevice
       within the system, and systems may have multiple graphics drivers (or
       even driver versions) which all support using the same underlying
       physical device. The combination of device UUID, driver UUID, and driver
       ID is currently found to be sufficient to uniquely identify any
       particular driver/device combination found in real-world scenarios.

Revision History

    Version 1, 2024-07-09 (Steven Noonan)
      - Initial draft