目錄

• Input Attachments
• • prepare
  • render
  • 小結
• Sub Passes
• • prepare
  • render
  • 小結
• Offscreen Renderings
• • prepare
  • render
  • 小結

Input Attachments

prepare

• loadAssets: 加載模型
• prepareUniformBuffers
  • updateUniformBuffers
• setupRenderPass: 重寫了父類的方法, 創建 Attachment

  • 創建的數量是: swapChain.imageCount

  • 每個 Attachment 都需要創建 color 和 depth 附件

    • VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT
    • VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT

  • 初始化每個 Attachment 的參數

  • 創建subpass： std::array<VkSubpassDescription,2> subpassDescriptions

    • VkAttachmentReference
    • 創建一個給 Attachment 填充顏色和深度的subpass
    • 創建一個swap chain 填充顏色的 subpass
    • 再創建兩個引用 VkAttachmentReference inputReferences
      • 將 fragment shader 中的輸出寫入Attachment : InputAttachments
    • swap chain 的subpass 中引入 InputAttachments, 填充顏色

  • 創建 VkSubpassDependency

    dependencies[0].srcSubpass = VK_SUBPASS_EXTERNAL;dependencies[0].dstSubpass = 0;//源為管線dependencies[0].srcStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;//輸出到 color attachment 中dependencies[0].dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;//讀取方式dependencies[0].srcAccessMask = VK_ACCESS_MEMORY_READ_BIT;dependencies[0].dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;dependencies[0].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;// This dependency transitions the input attachment from color attachment to shader readdependencies[1].srcSubpass = 0;dependencies[1].dstSubpass = 1;//源為 color attachmentdependencies[1].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;//輸出到 fragment shader 中dependencies[1].dstStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;dependencies[1].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;//讀取方式dependencies[1].dstAccessMask = VK_ACCESS_SHADER_READ_BIT;dependencies[1].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;dependencies[2].srcSubpass = 0;dependencies[2].dstSubpass = VK_SUBPASS_EXTERNAL;//源為 color attachment dependencies[2].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;// 輸出到管線中dependencies[2].dstStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;dependencies[2].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;dependencies[2].dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;dependencies[2].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;

  • vkCreateRenderPass

• setupDescriptors
  • 創建3個pool
    • VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER
    • VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER
    • VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT
  • Attachment write
    • vkCreateDescriptorSetLayout
    • vkCreatePipelineLayout
    • vkAllocateDescriptorSets
    • vkUpdateDescriptorSets
  • Attachment read
    • descriptorSetLayoutBinding: 三個
      • VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT: 顏色
      • VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT: 深度
      • VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER
    • vkCreateDescriptorSetLayout
    • vkCreatePipelineLayout
    • vkAllocateDescriptorSets
    • vkUpdateDescriptorSets
• preparePipelines: attachment 需創建兩個pipeline, 一個寫 Attachment, 一個讀 attachment
  • VkGraphicsPipelineCreateInfo: 多出了為Attachment配置的代碼
    • pipelineCI.renderPass = renderPass;
    • Attachment write
      • pipelineCI.subpass = 0;
      • pipelineCI.layout = pipelineLayouts.attachmentWrite;
    • vkCreateGraphicsPipelines
    • Attachment read
      • pipelineCI.subpass = 1
      • pipelineCI.layout = pipelineLayouts.attachmentRead;
    • vkCreateGraphicsPipelines
• buildCommandBuffers: 分別為兩個 subpass 創建 CommandBuffer /*First sub passFills the attachments*/{vks::debugmarker::beginRegion(drawCmdBuffers[i], "Subpass 0: Writing attachments", glm::vec4(1.0f, 1.0f, 1.0f, 1.0f));vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.attachmentWrite);vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayouts.attachmentWrite, 0, 1, &descriptorSets.attachmentWrite, 0, NULL);scene.draw(drawCmdBuffers[i]);vks::debugmarker::endRegion(drawCmdBuffers[i]);}/*Second sub passRender a full screen quad, reading from the previously written attachments via input attachments*/{vks::debugmarker::beginRegion(drawCmdBuffers[i], "Subpass 1: Reading attachments", glm::vec4(1.0f, 1.0f, 1.0f, 1.0f));vkCmdNextSubpass(drawCmdBuffers[i], VK_SUBPASS_CONTENTS_INLINE);vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.attachmentRead);vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayouts.attachmentRead, 0, 1, &descriptorSets.attachmentRead[i], 0, NULL);vkCmdDraw(drawCmdBuffers[i], 3, 1, 0, 0);vks::debugmarker::endRegion(drawCmdBuffers[i]);}

render

• draw
• updateUniformBuffers

小結

?? 本節主要講怎樣使用 Attachments 進行渲染. 但是我覺得這里的重點是怎樣使用subpass進行渲染.

Sub Passes

prepare

• loadAssets: 加載模型和紋理
• initLights: 設置光源
• prepareUniformBuffers
  • updateUniformBufferDeferredMatrices
  • updateUniformBufferDeferredLights
• setupFrameBuffer: 重寫父類方法
  • 當屏幕大小發生遍布重寫設置Gbuffer: createGBufferAttachments
  • writeDescriptorSets
  • vkUpdateDescriptorSets
  • 正向渲染
  • writeDescriptorSets
  • vkUpdateDescriptorSets
  • vkCreateFramebuffer
• setupRenderPass: 重寫父類方法
  • createGBufferAttachments: 創建Gbuffer
    • createAttachment – position
    • createAttachment – normal
    • createAttachment – albedo
  • VkAttachmentDescription: 有5個, 與上一節相似,主要設置,怎么寫入gbuffer,怎么從gbuffer讀數據
  • vkCreateRenderPass
• setupDescriptorSetLayout
  • vkCreateDescriptorSetLayout
  • vkCreatePipelineLayout
• preparePipelines: 中增加了 blendAttachmentStates
  • colorBlendState.attachmentCount = static_cast<uint32_t>(blendAttachmentStates.size());
  • colorBlendState.pAttachments = blendAttachmentStates.data();
• setupDescriptorPool
  • 創建3個pool
    • VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER
    • VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER
    • VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT
• setupDescriptorSet
  • vkAllocateDescriptorSets
  • writeDescriptorSets
• prepareCompositionPass:
  • Descriptor set layout
    • descriptorSetLayoutBinding
      • Position input attachment
      • Normal input attachment
      • Albedo input attachment
      • Light positions
        -vkCreateDescriptorSetLayout
  • Pipeline layout
    • vkCreatePipelineLayout
  • Descriptor sets
    • vkAllocateDescriptorSets
    • writeDescriptorSets
      • writeDescriptorSet
        • Position texture target
        • Normals texture target
        • Albedo texture target
        • Fragment shader lights
          -vkUpdateDescriptorSets
  • Pipeline
    • pipelineCreateInfo
    • vkCreateGraphicsPipelines
  • Transparent (forward) pipeline
    • vkCreateDescriptorSetLayout
    • vkCreatePipelineLayout
    • vkAllocateDescriptorSets
    • vkUpdateDescriptorSets
    • vkCreateGraphicsPipelines
• buildCommandBuffers: subpass有3個
  • 第一個將場景數據寫入Gbuffer
  • 第二個用gbuffer數據渲染到attachment中
  • 第三個正向渲染

render

• draw
• updateUniformBufferDeferredMatrices
• updateUniformBufferDeferredLights

小結

?? 本節主要講延遲渲染的方法. 總體來說就是更詳細介紹了subpass的使用方法.

Offscreen Renderings

prepare

• loadAssets: 加載模型
• prepareOffscreen: 準備離屏渲染資源
  • 準備的資源如下
  struct OffscreenPass {int32_t width, height;VkFramebuffer frameBuffer;FrameBufferAttachment color, depth;VkRenderPass renderPass;VkSampler sampler;VkDescriptorImageInfo descriptor;} offscreenPass;
  • vkCreateImage(color)
  • vkGetImageMemoryRequirements
  • vkAllocateMemory
  • vkBindImageMemory
  • vkCreateImageView
  • vkCreateSampler
  • vkCreateImage(depth)
  • vkGetImageMemoryRequirements
  • vkAllocateMemory
  • vkBindImageMemory
  • vkCreateImageView
  • attchmentDescriptions: 分別為color和depth
  • subpassDescription: 附加Attachment引用
  • vkCreateRenderPass
  • vkCreateFramebuffer: 將渲染后的資源寫入 frame buffer
• prepareUniformBuffers
  • updateUniformBuffers
  • updateUniformBufferOffscreen: 離屏pass更新uniform
• setupDescriptorSetLayout
  • vkCreateDescriptorSetLayout
  • vkCreatePipelineLayout
• preparePipelines: 新建四個pipelines
  • Render-target debug display
  • Mirror
  • Phong shading pipelines
  • Offscreen
• setupDescriptorPool
• setupDescriptorSet: 為三個pipeline設置
  • Mirror plane descriptor set (Mirror)
  • Shaded descriptor sets (Phong shading pipelines)
  • Offscreen
• buildCommandBuffers: subpass有2個
  • First render pass: Offscreen rendering
  • Scene rendering with applied radial blur

render

• draw
• updateUniformBuffers
• updateUniformBufferOffscreen

小結

?? 離屏渲染也就是將渲染結果寫入 attachment中 . 是 attachment 結合 subpass的一種實用方法.

總結

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