VkRenderPassCreateInfo contains the attachment indices used for Depth, Color and Input attachments. The corresponding image views are referenced in VkFramebufferCreateInfo in pAttachments. In the shader “input_attachment_index” identifies which input attachment the shader is using. Given that the framebuffer is bound during rendering, which should allow identification of the image view to be used for the input attachment, the same way it does for depth and color attachments.
I do not understand why Vulkan also requires mentioning the input attachment (but not other attachments) in descriptor set layouts and consequently in the bound descriptor set.
I feel like I am missing something here? What is it about input attachments that necessitates binding descriptors?
The same question was also asked here, I’ll try to mirror whatever comes out of it: https://stackoverflow.com/questions/43632903/vulkan-why-do-input-attachments-need-a-descriptor-set-to-be-bound