VK_EXT_fragment_density_map(3) Manual Page

// Create fragment density map
VkImageCreateInfo imageCreateInfo =
{
   ​VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,
   nullptr,
   0,
   VK_IMAGE_TYPE_2D,       // Must be 2D
   VK_FORMAT_R8G8_UNORM,   // Must have VK_FORMAT_FEATURE_FRAGMENT_DENSITY_MAP_BIT_EXT
   {64, 64, 1},            // extent
   1,                      // mipLevels
   2,                      // arrayLayers; 1 for each multiview view
   VK_SAMPLE_COUNT_1_BIT,  // Must be 1x MSAA
   tiling,
   VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT,
   // ...
};

vkCreateImage(device, &imageCreateInfo, nullptr, &fdmImage);

VkImageViewCreateInfo viewCreateInfo =
{
   ​VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO,
   nullptr,
   0,                          // VkImageViewCreateFlags
   fdmImage,
   VK_IMAGE_VIEW_TYPE_2D_ARRAY,
   VK_FORMAT_R8G8_UNORM,
   {0},                        // VK_COMPONENT_SWIZZLE_IDENTITY
   {VK_IMAGE_ASPECT_COLOR_BIT,
    0,                         // baseMipLevel
    1,                         // levelCount; must be 1
    0,                         // baseArrayLayer
    2,                         // layerCount
   }
};

vkCreateImageView(device, &viewCreateInfo, nullptr, &fdmImageView);

// Add fdmImage to render pass

VkAttachmentReference fragmentDensityMapAttachmentReference =
{
   ​fdmAttachmentIdx,
   VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT,
};

VkRenderPassFragmentDensityMapCreateInfoEXT fdmAttachmentCreateInfo =
{
   ​VK_STRUCTURE_TYPE_RENDER_PASS_FRAGMENT_DENSITY_MAP_CREATE_INFO_EXT,
   // ...
   fragmentDensityMapAttachmentReference,
};

VkRenderPassCreateInfo2 renderPassCreateInfo =
{
   ​VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO_2,
   &fdmAttachmentCreateInfo,
   // ...
};

vkCreateRenderPass2(device, &renderPassCreateInfo, nullptr, &renderPass);

// Add fdmImage to framebuffer
// Color attachments can be created with VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT
// All attachments must be created with VK_IMAGE_CREATE_FRAGMENT_DENSITY_MAP_OFFSETS_BIT_EXT
VkFramebufferCreateInfo framebufferCreateInfo =
{
   ​VK_STRUCTURE_TYPE_FRAME_BUFFER_CREATE_INFO,
   // ...
   renderPass,
   // ...
   pAttachments, // Includes fdmImageView at fdmAttachmentIdx
   1024,         // width
   1024,         // height
   1             // layers; must be 1 if using multiview
};

vkCreateFramebuffer(device, &framebufferCreateInfo, nullptr, &framebuffer);

// Start recording render pass in command buffer

VkRenderPassBeginInfo renderPassBeginInfo =
{
   ​VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO,
   // ...
   renderPass,
   framebuffer,
   // ...
};

// Can no longer modify the fdmImage's contents after this call
vkCmdBeginRenderPass2(commandBuffer, &renderPassBeginInfo, pSubpassBeginInfo);