Destroying a descriptor pool

When we don't need a descriptor pool any more, we can destroy it (with all descriptor sets allocated from the pool).

How to do it...

1. Take the handle of a created logical device and store it in a variable of type VkDevice named logical_device.
2. Provide the handle of the descriptor pool through a variable of type VkDescriptorPool named descriptor_pool.
3. Call vkDestroyDescriptorPool( logical_device, descriptor_pool, nullptr ) and provide the logical_device and descriptor_pool variables and a nullptr value.
4. For safety, assign the VK_NULL_HANDLE value to the descriptor_pool variable.

How it works...

Destroying a descriptor pool implicitly frees all descriptor sets allocated from it. We don't need to free individual descriptor sets first. But because of this, we need to make sure that none of the descriptor sets allocated from the pool are referenced by the commands that are currently processed by the hardware.

When we are ready, we can destroy a descriptor pool like this:

if...