Specifying subpass descriptions

Operations performed in a render pass are grouped into subpasses. Each subpass represents a stage or a phase of our rendering commands in which a subset of render pass's attachments are used (into which we render or from which we read data).

A render pass always requires at least one subpass that is automatically started when we begin a render pass. And for each subpass, we need to prepare a description.

Getting ready

To lower the number of parameters required to prepare for each subpass, a custom structure type is introduced for this recipe. It is a simplified version of a VkSubpassDescription structure defined in the Vulkan header. It has the following definition:

struct SubpassParameters { 
  VkPipelineBindPoint                  PipelineType; 
  std::vector<VkAttachmentReference>   InputAttachments; 
  std::vector<VkAttachmentReference>   ColorAttachments; 
  std::vector<VkAttachmentReference>   ResolveAttachments; 
  VkAttachmentReference...