Destroying a sampler

When we no longer need a sampler and we are sure it is not used anymore by the pending commands, we can destroy it.

How to do it...

1. Take the handle of a logical device on which the sampler was created and store it in a variable of type VkDevice named logical_device.
2. Take the handle of the sampler that should be destroyed. Provide it through a variable of type VkSampler named sampler.
3. Call vkDestroySampler( logical_device, sampler, nullptr ) and provide the logical_device and sampler variables, and a nullptr value.
4. For safety, assign the VK_NULL_HANDLE value to the sampler variable.

How it works...

Samplers are destroyed like this:

if( VK_NULL_HANDLE != sampler ) { 
  vkDestroySampler( logical_device, sampler, nullptr ); 
  sampler = VK_NULL_HANDLE; 
}

We don't have to check whether the sampler's handle is not empty, because a deletion of a VK_NULL_HANDLE is ignored. We do this just to avoid an unnecessary function call. But when we delete a sampler, we must be sure that the handle...