Clarify language on instance function loading

This commit is contained in:
Camilla Berglund 2016-02-17 15:03:26 +01:00
parent 95c44ab298
commit 08ea80b708

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@ -45,6 +45,10 @@ of GLFW to work. Define them only if you are using these extensions directly.
@section vulkan_support Querying for Vulkan support
If you are linking directly against the Vulkan loader then you can skip this
section. The canonical desktop loader library exports all Vulkan core and
Khronos extension functions, allowing them to be called directly.
If you are loading the Vulkan loader dynamically instead of linking directly
against it, you can check for the availability of a loader with @ref
glfwVulkanSupported.
@ -66,14 +70,23 @@ generate a @ref GLFW_API_UNAVAILABLE error.
@subsection vulkan_proc Querying Vulkan function pointers
To load any Vulkan core or extension function from the found loader, call @ref
glfwGetInstanceProcAddress.
glfwGetInstanceProcAddress. To load functions needed for instance creation,
pass `NULL` as the instance.
@code
PFN_vkCreateInstance pfnCreateInstance = (PFN_vkCreateInstance)
glfwGetInstanceProcAddress(NULL, "vkCreateInstance");
@endcode
Once you have created an instance, you can load from it all other Vulkan core
functions and functions from any instance extensions you enabled.
@code
PFN_vkCreateDevice pfnCreateDevice = (PFN_vkCreateDevice)
glfwGetInstanceProcAddress(instance, "vkCreateDevice");
@endcode
This is equivalent to calling `vkGetInstanceProcAddr`. If that fails, the
This function in turn calls `vkGetInstanceProcAddr`. If that fails, the
function falls back to a platform-specific query of the Vulkan loader (i.e.
`dlsym` or `GetProcAddress`). If that also fails, the function returns `NULL`.
For more information about `vkGetInstanceProcAddr`, see the Vulkan