Proper way to check for a device extension?

[gwaldron]

I want to enable a device extension, so I am calling

traits->deviceExtensionNames.push_back(VK_KHR_FRAGMENT_SHADER_BARYCENTRIC_EXTENSION_NAME);

before creating my window. This works, but I want to check for support first so VSG doesn't throw an exception. I found vsg::Device::supportsDeviceExtension but I don't have a vsg::Device before calling vsg::Window::create().

What's the canonical way to go about this? Do I have to manually create the device first?

[gwaldron]

Figured it out:

    auto window = vsg::Window::create(traits);

    auto pd = window->getOrCreatePhysicalDevice();

    if (pd->supportsDeviceExtension(VK_KHR_FRAGMENT_SHADER_BARYCENTRIC_EXTENSION_NAME))
    {
        traits->deviceExtensionNames.push_back(VK_KHR_FRAGMENT_SHADER_BARYCENTRIC_EXTENSION_NAME);
    }

I was confusing PhysicalDevice::supportsDeviceExtension (which says whether the device supports it) and Device::supportsDeviceExtension (which says whether you have tried to enabled it).

[robertosfield]

You beat me to it :-)

I was going to suggest creating a PhysicalDevice then querying the supported features/extensions.

You can create a PhyscialDevice independently of a window, but if you're about to create a window then using it's getOrCreatePhysicalDevice() is fine, you just need to do they query before finally creating the logical device (vk/vsg::Device.)