Initialization
Before using Vulkan, an application must initialize it by loading the
Vulkan commands, and creating a VkInstance object.
Command Function Pointers
Vulkan commands are not necessarily exposed by static linking on a platform. Commands to query function pointers for Vulkan commands are described below.
When extensions are promoted or otherwise incorporated into another extension or Vulkan core version, command aliases may be included. Whilst the behavior of each command alias is identical, the behavior of retrieving each alias’s function pointer is not. A function pointer for a given alias can only be retrieved if the extension or version that introduced that alias is supported and enabled, irrespective of whether any other alias is available.
Extending Physical Device From Device Extensions
When the VK_KHR_get_physical_device_properties2 extension is enabled, physical-device-level functionality of a device extension can be used with a physical device if the corresponding extension is enumerated by vkEnumerateDeviceExtensionProperties for that physical device, even before a logical device has been created.
To obtain a function pointer for a physical-device-level command from a
device extension, an application can use vkGetInstanceProcAddr.
This function pointer may point to dispatch code, which calls a different
real implementation for different VkPhysicalDevice objects.
Applications must not use a VkPhysicalDevice in any command added by
an extension or core version that is not supported by that physical device.
Device extensions may define structures that can be added to the
pNext chain of physical-device-level commands.
Instances
Disabling checks such as parameter validation and object lifetime validation prevents the reporting of error conditions that can cause other validation checks to behave incorrectly or crash. Some validation checks assume that their inputs are already valid and do not always revalidate them.
The VK_EXT_validation_features extension subsumes all the functionality provided in the VK_EXT_validation_flags extension.