Vulkan validation layers contain a set of libraries which help find potential problems in created applications. Their debugging capabilities include, but are not limited to, validating parameters passed to Vulkan functions, validating texture and render target formats, tracking Vulkan objects and their lifetime and usage, and checking for potential memory leaks or dumping (displaying/printing) Vulkan API function calls. These functionalities are enabled by different validation layers, but most of them are gathered into a single layer called VK_LAYER_LUNARG_standard_validation which is enabled in this recipe. Examples of names of other layers include VK_LAYER_LUNARG_swapchain, VK_LAYER_LUNARG_object_tracker, VK_LAYER_GOOGLE_threading, or VK_LAYER_LUNARG_api_dump, among others. Multiple layers can be enabled at the same time, in a similar way as presented here in the recipe. Just assign the names of the layers you want to activate to the VK_INSTANCE_LAYERS environment variable. If you are a Windows OS user, remember to separate them with a semicolon, as in the example:
setx VK_INSTANCE_LAYERS VK_LAYER_LUNARG_api_dump;VK_LAYER_LUNARG_core_validation
If you are a Linux OS user, separate them with a colon. Here is an example:
export VK_INSTANCE_LAYERS=VK_LAYER_LUNARG_api_dump:VK_LAYER_LUNARG _core_validation
The environment variable named VK_INSTANCE_LAYERS can be also set with other OS specific ways such as, advanced operating system settings on Windows or /etc/environment on Linux.
The preceding examples enable validation layers globally, for all applications, but they can also be enabled only for our own application, in its source code during Instance creation. However, this approach requires us to recompile the whole program every time we want to enable or disable different layers. So, it is easier to enable them using the preceding recipe. This way, we also won't forget to disable them when we want to ship the final version of our application. To disable validation layers, we just have to delete VK_INSTANCE_LAYERS environment variable.
Validation layers should not be enabled in the released (shipped) version of the applications as they may drastically decrease performance.
For a full list of available validation layers, please refer to the documentation, which can be found in the Documentation sub-folder of the directory in which the Vulkan SDK was installed.
