渲染流程
现在让我们修改createRenderPass函数，通过VkAttachementDescription结构体设置深度附着信息：
VkAttachmentDescription depthAttachment = {};
depthAttachment.format = findDepthFormat();
depthAttachment.samples = VK_SAMPLE_COUNT_1_BIT;
depthAttachment.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
depthAttachment.storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
depthAttachment.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
depthAttachment.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
depthAttachment.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
depthAttachment.finalLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
format成员变量的值的设置应该和深度图像的图像数据格式相同。我们在绘制结束后不需要从深度缓冲中复制深度数据，所以将storeOp成员变量设置为VK_ATTACHMENT_STORE_OP_DONT_CARE。这一设置可以让驱动进行一定程度的优化。同样，我们不需要读取之前深度图像数据，所以将initialLayout成员变量设置为VK_IMAGE_LAYOUT_UNDEFINED。
VkAttachmentReference depthAttachmentRef = {};
depthAttachmentRef.attachment = 1;
depthAttachmentRef.layout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
为我们仅有的子流程添加对深度附着的引用：
VkSubpassDescription subpass = {};
subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
subpass.colorAttachmentCount = 1;
subpass.pColorAttachments = &colorAttachmentRef;
subpass.pDepthStencilAttachment = &depthAttachmentRef;
和颜色附着不同，一个子流程只可以使用一个深度(或深度模板)附着。一般而言，也很少有需要多个深度附着的情况。
std::array<VkAttachmentDescription, 2> attachments = {colorAttachment, depthAttachment};
VkRenderPassCreateInfo renderPassInfo = {};
renderPassInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO;
renderPassInfo.attachmentCount = static_cast<uint32_t>(attachments.size());
renderPassInfo.pAttachments = attachments.data();
renderPassInfo.subpassCount = 1;
renderPassInfo.pSubpasses = &subpass;
renderPassInfo.dependencyCount = 1;
renderPassInfo.pDependencies = &dependency;
最后，更新VkRenderPassCreateInfo结构体信息引用深度附着。