やっていくVulkan入門

4-5. キューとプレゼンテーション

以前に説明したように、イメージの表示(プレゼンテーション)もGPUの仕事です。GPUの仕事ということはつまり、キューにコマンドを送信することになります。

ここでまた少し面倒な部分です。どの物理デバイスのどのキューかによって、プレゼンテーションの機能をサポートしている場合とサポートしていない場合があり得ます。ということは、物理デバイス厳選がまた始まりますね。

ある物理デバイスのあるキューが、あるサーフェスへのプレゼンテーションを行えるかどうかという情報は、物理デバイスのgetSurfaceSupportKHRというメソッドで行えます。これによる判定処理を物理デバイス選定処理の部分に追加します。以下のように書き換えてください。

for (size_t i = 0; i < physicalDevices.size(); i++) {
    std::vector<vk::QueueFamilyProperties> queueProps = physicalDevices[i].getQueueFamilyProperties();
    bool existsGraphicsQueue = false;

    for (size_t j = 0; j < queueProps.size(); j++) {
        if (queueProps[j].queueFlags & vk::QueueFlagBits::eGraphics &&
            physicalDevices[i].getSurfaceSupportKHR(j, surface.get())) {    // 追加
            existsGraphicsQueue = true;
            graphicsQueueFamilyIndex = j;
            break;
        }
    }

    std::vector<vk::ExtensionProperties> extProps = physicalDevices[i].enumerateDeviceExtensionProperties();
    bool supportsSwapchainExtension = false;

    for (size_t j = 0; j < extProps.size(); j++) {
        if (std::string_view(extProps[j].extensionName.data()) == VK_KHR_SWAPCHAIN_EXTENSION_NAME) {
            supportsSwapchainExtension = true;
            break;
        }
    }

    if (existsGraphicsQueue && supportsSwapchainExtension) {
        physicalDevice = physicalDevices[i];
        existsSuitablePhysicalDevice = true;
        break;
    }
}

getSurfaceSupportKHRは第一引数にキューのインデックス、第二引数にサーフェスを指定します。前回までは「グラフィックス機能をサポートしているキューのみを厳選」という風になっていた部分が、「グラフィックス機能に加えてサーフェスへのプレゼンテーションもサポートしているキューを厳選」という処理に変わりました。

これでデバイスの準備はOKです。


先ほど説明したように、プレゼンテーションはGPUの仕事です。プレゼンテーションを行うにはキューにそのコマンドを送る必要があります。

ということはコマンドバッファにコマンドを…と行きたいところですが、今回はコマンドバッファは経由しません。プレゼンテーションのコマンドはキューに直接送信するAPIがあるので、それを使用します。

どうしてこういう仕様になってるのかよく知らないので知ってる方は教えて下さると嬉しいです…

プレゼンテーションはキューpresentKHRメソッドで行います。以下のコードを描画処理の後に追加してください。

vk::PresentInfoKHR presentInfo;

auto presentSwapchains = { swapchain.get() };
auto imgIndices = { imgIndex };

presentInfo.swapchainCount = presentSwapchains.size();
presentInfo.pSwapchains = presentSwapchains.begin();
presentInfo.pImageIndices = imgIndices.begin();

graphicsQueue.presentKHR(presentInfo);

graphicsQueue.waitIdle();

スワップチェーンおよび、プレゼンテーションを行うイメージを番号で指定します。一度に複数のスワップチェーンを扱えるようですが、今回は1つだけですね。

ここまでのコードを実行してみましょう。

ようやく画面に三角形が表示されたはずです。長い長い道のりでした。これで一応、最低限動くものは完成です!

ちなみにFPSは自動的にモニタの設定どおりに調整されます。acquireNextImageKHRやその待ち処理で待機されるようです。

お疲れさまでした、と言いたいところですが、今回書いたプログラムでは説明を簡単にするためにいくつか「本当はやった方が良い」処理などを飛ばしました。ということで、まだもう少しだけ続きます。


今回は描画した三角形を画面に表示するところまでやりました。

次節では処理を非同期にします。今まではフェンスやwaitIdle()などを使って処理毎に完了を待っていたところを、各処理をまとめて行わせるようにします。

この節のコード
#include <iostream>
#include <fstream>
#include <filesystem>
#include <vulkan/vulkan.hpp>
#include <GLFW/glfw3.h>

const uint32_t screenWidth = 640;
const uint32_t screenHeight = 480;

int main() {
    if (!glfwInit())
        return -1;

    uint32_t requiredExtensionsCount;
    const char** requiredExtensions = glfwGetRequiredInstanceExtensions(&requiredExtensionsCount);

    vk::InstanceCreateInfo createInfo;
    createInfo.enabledExtensionCount = requiredExtensionsCount;
    createInfo.ppEnabledExtensionNames = requiredExtensions;

    vk::UniqueInstance instance;
    instance = vk::createInstanceUnique(createInfo);

    glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
    GLFWwindow* window;
    window = glfwCreateWindow(screenWidth, screenHeight, "GLFW Test Window", NULL, NULL);
    if (!window) {
        const char* err;
        glfwGetError(&err);
        std::cout << err << std::endl;
        glfwTerminate();
        return -1;
    }

    VkSurfaceKHR c_surface;
    auto result = glfwCreateWindowSurface(instance.get(), window, nullptr, &c_surface);
    if (result != VK_SUCCESS) {
        const char* err;
        glfwGetError(&err);
        std::cout << err << std::endl;
        glfwTerminate();
        return -1;
    }
    vk::UniqueSurfaceKHR surface{ c_surface, instance.get() };

    std::vector<vk::PhysicalDevice> physicalDevices = instance->enumeratePhysicalDevices();

    vk::PhysicalDevice physicalDevice;
    bool existsSuitablePhysicalDevice = false;
    uint32_t graphicsQueueFamilyIndex;

    for (size_t i = 0; i < physicalDevices.size(); i++) {
        std::vector<vk::QueueFamilyProperties> queueProps = physicalDevices[i].getQueueFamilyProperties();
        bool existsGraphicsQueue = false;

        for (size_t j = 0; j < queueProps.size(); j++) {
            if (queueProps[j].queueFlags & vk::QueueFlagBits::eGraphics &&
                physicalDevices[i].getSurfaceSupportKHR(j, surface.get())) {
                existsGraphicsQueue = true;
                graphicsQueueFamilyIndex = j;
                break;
            }
        }

        std::vector<vk::ExtensionProperties> extProps = physicalDevices[i].enumerateDeviceExtensionProperties();
        bool supportsSwapchainExtension = false;

        for (size_t j = 0; j < extProps.size(); j++) {
            if (std::string_view(extProps[j].extensionName.data()) == VK_KHR_SWAPCHAIN_EXTENSION_NAME) {
                supportsSwapchainExtension = true;
                break;
            }
        }

        if (existsGraphicsQueue && supportsSwapchainExtension) {
            physicalDevice = physicalDevices[i];
            existsSuitablePhysicalDevice = true;
            break;
        }
    }

    if (!existsSuitablePhysicalDevice) {
        std::cerr << "使用可能な物理デバイスがありません。" << std::endl;
        return -1;
    }

    vk::DeviceCreateInfo devCreateInfo;

    auto devRequiredExtensions = { VK_KHR_SWAPCHAIN_EXTENSION_NAME };

    devCreateInfo.enabledExtensionCount = devRequiredExtensions.size();
    devCreateInfo.ppEnabledExtensionNames = devRequiredExtensions.begin();

    vk::DeviceQueueCreateInfo queueCreateInfo[1];
    queueCreateInfo[0].queueFamilyIndex = graphicsQueueFamilyIndex;
    queueCreateInfo[0].queueCount = 1;

    float queuePriorities[1] = { 1.0 };

    queueCreateInfo[0].pQueuePriorities = queuePriorities;

    devCreateInfo.pQueueCreateInfos = queueCreateInfo;
    devCreateInfo.queueCreateInfoCount = 1;

    vk::UniqueDevice device = physicalDevice.createDeviceUnique(devCreateInfo);

    vk::Queue graphicsQueue = device->getQueue(graphicsQueueFamilyIndex, 0);

    vk::SurfaceCapabilitiesKHR surfaceCapabilities = physicalDevice.getSurfaceCapabilitiesKHR(surface.get());
    std::vector<vk::SurfaceFormatKHR> surfaceFormats = physicalDevice.getSurfaceFormatsKHR(surface.get());
    std::vector<vk::PresentModeKHR> surfacePresentModes = physicalDevice.getSurfacePresentModesKHR(surface.get());

    vk::SurfaceFormatKHR swapchainFormat = surfaceFormats[0];
    vk::PresentModeKHR swapchainPresentMode = surfacePresentModes[0];

    vk::SwapchainCreateInfoKHR swapchainCreateInfo;
    swapchainCreateInfo.surface = surface.get();
    swapchainCreateInfo.minImageCount = surfaceCapabilities.minImageCount + 1;
    swapchainCreateInfo.imageFormat = swapchainFormat.format;
    swapchainCreateInfo.imageColorSpace = swapchainFormat.colorSpace;
    swapchainCreateInfo.imageExtent = surfaceCapabilities.currentExtent;
    swapchainCreateInfo.imageArrayLayers = 1;
    swapchainCreateInfo.imageUsage = vk::ImageUsageFlagBits::eColorAttachment;
    swapchainCreateInfo.imageSharingMode = vk::SharingMode::eExclusive;
    swapchainCreateInfo.preTransform = surfaceCapabilities.currentTransform;
    swapchainCreateInfo.presentMode = swapchainPresentMode;
    swapchainCreateInfo.clipped = VK_TRUE;

    vk::UniqueSwapchainKHR swapchain = device->createSwapchainKHRUnique(swapchainCreateInfo);

    std::vector<vk::Image> swapchainImages = device->getSwapchainImagesKHR(swapchain.get());

    vk::AttachmentDescription attachments[1];
    attachments[0].format = swapchainFormat.format;
    attachments[0].samples = vk::SampleCountFlagBits::e1;
    attachments[0].loadOp = vk::AttachmentLoadOp::eClear;
    attachments[0].storeOp = vk::AttachmentStoreOp::eStore;
    attachments[0].stencilLoadOp = vk::AttachmentLoadOp::eDontCare;
    attachments[0].stencilStoreOp = vk::AttachmentStoreOp::eDontCare;
    attachments[0].initialLayout = vk::ImageLayout::eUndefined;
    attachments[0].finalLayout = vk::ImageLayout::ePresentSrcKHR;

    vk::AttachmentReference subpass0_attachmentRefs[1];
    subpass0_attachmentRefs[0].attachment = 0;
    subpass0_attachmentRefs[0].layout = vk::ImageLayout::eColorAttachmentOptimal;

    vk::SubpassDescription subpasses[1];
    subpasses[0].pipelineBindPoint = vk::PipelineBindPoint::eGraphics;
    subpasses[0].colorAttachmentCount = 1;
    subpasses[0].pColorAttachments = subpass0_attachmentRefs;

    vk::RenderPassCreateInfo renderpassCreateInfo;
    renderpassCreateInfo.attachmentCount = 1;
    renderpassCreateInfo.pAttachments = attachments;
    renderpassCreateInfo.subpassCount = 1;
    renderpassCreateInfo.pSubpasses = subpasses;
    renderpassCreateInfo.dependencyCount = 0;
    renderpassCreateInfo.pDependencies = nullptr;

    vk::UniqueRenderPass renderpass = device->createRenderPassUnique(renderpassCreateInfo);

    vk::Viewport viewports[1];
    viewports[0].x = 0.0;
    viewports[0].y = 0.0;
    viewports[0].minDepth = 0.0;
    viewports[0].maxDepth = 1.0;
    viewports[0].width = screenWidth;
    viewports[0].height = screenHeight;

    vk::Rect2D scissors[1];
    scissors[0].offset = vk::Offset2D{ 0, 0 };
    scissors[0].extent = vk::Extent2D{ screenWidth, screenHeight };

    vk::PipelineViewportStateCreateInfo viewportState;
    viewportState.viewportCount = 1;
    viewportState.pViewports = viewports;
    viewportState.scissorCount = 1;
    viewportState.pScissors = scissors;

    vk::PipelineVertexInputStateCreateInfo vertexInputInfo;
    vertexInputInfo.vertexAttributeDescriptionCount = 0;
    vertexInputInfo.pVertexAttributeDescriptions = nullptr;
    vertexInputInfo.vertexBindingDescriptionCount = 0;
    vertexInputInfo.pVertexBindingDescriptions = nullptr;

    vk::PipelineInputAssemblyStateCreateInfo inputAssembly;
    inputAssembly.topology = vk::PrimitiveTopology::eTriangleList;
    inputAssembly.primitiveRestartEnable = false;

    vk::PipelineRasterizationStateCreateInfo rasterizer;
    rasterizer.depthClampEnable = false;
    rasterizer.rasterizerDiscardEnable = false;
    rasterizer.polygonMode = vk::PolygonMode::eFill;
    rasterizer.lineWidth = 1.0f;
    rasterizer.cullMode = vk::CullModeFlagBits::eBack;
    rasterizer.frontFace = vk::FrontFace::eClockwise;
    rasterizer.depthBiasEnable = false;

    vk::PipelineMultisampleStateCreateInfo multisample;
    multisample.sampleShadingEnable = false;
    multisample.rasterizationSamples = vk::SampleCountFlagBits::e1;

    vk::PipelineColorBlendAttachmentState blendattachment[1];
    blendattachment[0].colorWriteMask =
        vk::ColorComponentFlagBits::eA |
        vk::ColorComponentFlagBits::eR |
        vk::ColorComponentFlagBits::eG |
        vk::ColorComponentFlagBits::eB;
    blendattachment[0].blendEnable = false;

    vk::PipelineColorBlendStateCreateInfo blend;
    blend.logicOpEnable = false;
    blend.attachmentCount = 1;
    blend.pAttachments = blendattachment;

    vk::PipelineLayoutCreateInfo layoutCreateInfo;
    layoutCreateInfo.setLayoutCount = 0;
    layoutCreateInfo.pSetLayouts = nullptr;

    vk::UniquePipelineLayout pipelineLayout = device->createPipelineLayoutUnique(layoutCreateInfo);

    size_t vertSpvFileSz = std::filesystem::file_size("shader.vert.spv");

    std::ifstream vertSpvFile("shader.vert.spv", std::ios_base::binary);

    std::vector<char> vertSpvFileData(vertSpvFileSz);
    vertSpvFile.read(vertSpvFileData.data(), vertSpvFileSz);

    vk::ShaderModuleCreateInfo vertShaderCreateInfo;
    vertShaderCreateInfo.codeSize = vertSpvFileSz;
    vertShaderCreateInfo.pCode = reinterpret_cast<const uint32_t*>(vertSpvFileData.data());

    vk::UniqueShaderModule vertShader = device->createShaderModuleUnique(vertShaderCreateInfo);

    size_t fragSpvFileSz = std::filesystem::file_size("shader.frag.spv");

    std::ifstream fragSpvFile("shader.frag.spv", std::ios_base::binary);

    std::vector<char> fragSpvFileData(fragSpvFileSz);
    fragSpvFile.read(fragSpvFileData.data(), fragSpvFileSz);

    vk::ShaderModuleCreateInfo fragShaderCreateInfo;
    fragShaderCreateInfo.codeSize = fragSpvFileSz;
    fragShaderCreateInfo.pCode = reinterpret_cast<const uint32_t*>(fragSpvFileData.data());

    vk::UniqueShaderModule fragShader = device->createShaderModuleUnique(fragShaderCreateInfo);

    vk::PipelineShaderStageCreateInfo shaderStage[2];
    shaderStage[0].stage = vk::ShaderStageFlagBits::eVertex;
    shaderStage[0].module = vertShader.get();
    shaderStage[0].pName = "main";
    shaderStage[1].stage = vk::ShaderStageFlagBits::eFragment;
    shaderStage[1].module = fragShader.get();
    shaderStage[1].pName = "main";

    vk::GraphicsPipelineCreateInfo pipelineCreateInfo;
    pipelineCreateInfo.pViewportState = &viewportState;
    pipelineCreateInfo.pVertexInputState = &vertexInputInfo;
    pipelineCreateInfo.pInputAssemblyState = &inputAssembly;
    pipelineCreateInfo.pRasterizationState = &rasterizer;
    pipelineCreateInfo.pMultisampleState = &multisample;
    pipelineCreateInfo.pColorBlendState = &blend;
    pipelineCreateInfo.layout = pipelineLayout.get();
    pipelineCreateInfo.renderPass = renderpass.get();
    pipelineCreateInfo.subpass = 0;
    pipelineCreateInfo.stageCount = 2;
    pipelineCreateInfo.pStages = shaderStage;

    vk::UniquePipeline pipeline = device->createGraphicsPipelineUnique(nullptr, pipelineCreateInfo).value;

    std::vector<vk::UniqueImageView> swapchainImageViews(swapchainImages.size());

    for (size_t i = 0; i < swapchainImages.size(); i++) {
        vk::ImageViewCreateInfo imgViewCreateInfo;
        imgViewCreateInfo.image = swapchainImages[i];
        imgViewCreateInfo.viewType = vk::ImageViewType::e2D;
        imgViewCreateInfo.format = swapchainFormat.format;
        imgViewCreateInfo.components.r = vk::ComponentSwizzle::eIdentity;
        imgViewCreateInfo.components.g = vk::ComponentSwizzle::eIdentity;
        imgViewCreateInfo.components.b = vk::ComponentSwizzle::eIdentity;
        imgViewCreateInfo.components.a = vk::ComponentSwizzle::eIdentity;
        imgViewCreateInfo.subresourceRange.aspectMask = vk::ImageAspectFlagBits::eColor;
        imgViewCreateInfo.subresourceRange.baseMipLevel = 0;
        imgViewCreateInfo.subresourceRange.levelCount = 1;
        imgViewCreateInfo.subresourceRange.baseArrayLayer = 0;
        imgViewCreateInfo.subresourceRange.layerCount = 1;

        swapchainImageViews[i] = device->createImageViewUnique(imgViewCreateInfo);
    }

    std::vector<vk::UniqueFramebuffer> swapchainFramebufs(swapchainImages.size());

    for (size_t i = 0; i < swapchainImages.size(); i++) {
        vk::ImageView frameBufAttachments[1];
        frameBufAttachments[0] = swapchainImageViews[i].get();

        vk::FramebufferCreateInfo frameBufCreateInfo;
        frameBufCreateInfo.width = surfaceCapabilities.currentExtent.width;
        frameBufCreateInfo.height = surfaceCapabilities.currentExtent.height;
        frameBufCreateInfo.layers = 1;
        frameBufCreateInfo.renderPass = renderpass.get();
        frameBufCreateInfo.attachmentCount = 1;
        frameBufCreateInfo.pAttachments = frameBufAttachments;

        swapchainFramebufs[i] = device->createFramebufferUnique(frameBufCreateInfo);
    }

    vk::CommandPoolCreateInfo cmdPoolCreateInfo;
    cmdPoolCreateInfo.queueFamilyIndex = graphicsQueueFamilyIndex;
    cmdPoolCreateInfo.flags = vk::CommandPoolCreateFlagBits::eResetCommandBuffer;
    vk::UniqueCommandPool cmdPool = device->createCommandPoolUnique(cmdPoolCreateInfo);

    vk::CommandBufferAllocateInfo cmdBufAllocInfo;
    cmdBufAllocInfo.commandPool = cmdPool.get();
    cmdBufAllocInfo.commandBufferCount = 1;
    cmdBufAllocInfo.level = vk::CommandBufferLevel::ePrimary;
    std::vector<vk::UniqueCommandBuffer> cmdBufs =
        device->allocateCommandBuffersUnique(cmdBufAllocInfo);
        
    vk::FenceCreateInfo fenceCreateInfo;
    vk::UniqueFence swapchainImgFence = device->createFenceUnique(fenceCreateInfo);

    while (!glfwWindowShouldClose(window)) {
        glfwPollEvents();

        device->resetFences({ swapchainImgFence.get() });

        vk::ResultValue acquireImgResult = device->acquireNextImageKHR(swapchain.get(), 1'000'000'000, {}, swapchainImgFence.get());
        if (acquireImgResult.result != vk::Result::eSuccess) {
            std::cerr << "次フレームの取得に失敗しました。" << std::endl;
            return -1;
        }
        uint32_t imgIndex = acquireImgResult.value;

        if (device->waitForFences({ swapchainImgFence.get() }, VK_TRUE, 1'000'000'000) != vk::Result::eSuccess) {
            std::cerr << "次フレームの取得に失敗しました。" << std::endl;
            return -1;
        }

        cmdBufs[0]->reset();

        vk::CommandBufferBeginInfo cmdBeginInfo;
        cmdBufs[0]->begin(cmdBeginInfo);

        vk::ClearValue clearVal[1];
        clearVal[0].color.float32[0] = 0.0f;
        clearVal[0].color.float32[1] = 0.0f;
        clearVal[0].color.float32[2] = 0.0f;
        clearVal[0].color.float32[3] = 1.0f;

        vk::RenderPassBeginInfo renderpassBeginInfo;
        renderpassBeginInfo.renderPass = renderpass.get();
        renderpassBeginInfo.framebuffer = swapchainFramebufs[imgIndex].get();
        renderpassBeginInfo.renderArea = vk::Rect2D({ 0,0 }, { screenWidth, screenHeight });
        renderpassBeginInfo.clearValueCount = 1;
        renderpassBeginInfo.pClearValues = clearVal;

        cmdBufs[0]->beginRenderPass(renderpassBeginInfo, vk::SubpassContents::eInline);

        cmdBufs[0]->bindPipeline(vk::PipelineBindPoint::eGraphics, pipeline.get());
        cmdBufs[0]->draw(3, 1, 0, 0);

        cmdBufs[0]->endRenderPass();

        cmdBufs[0]->end();

        vk::CommandBuffer submitCmdBuf[1] = { cmdBufs[0].get() };
        vk::SubmitInfo submitInfo;
        submitInfo.commandBufferCount = 1;
        submitInfo.pCommandBuffers = submitCmdBuf;
        graphicsQueue.submit({ submitInfo }, nullptr);

        graphicsQueue.waitIdle();

        vk::PresentInfoKHR presentInfo;

        auto presentSwapchains = { swapchain.get() };
        auto imgIndices = { imgIndex };

        presentInfo.swapchainCount = presentSwapchains.size();
        presentInfo.pSwapchains = presentSwapchains.begin();
        presentInfo.pImageIndices = imgIndices.begin();

        graphicsQueue.presentKHR(presentInfo);

        graphicsQueue.waitIdle();
    }

    glfwTerminate();
    return 0;
}
#version 450
#extension GL_ARB_separate_shader_objects : enable

void main() {
    if(gl_VertexIndex == 0) {
        gl_Position = vec4(0.0, -0.5, 0.0, 1.0);
    } else if(gl_VertexIndex == 1) {
        gl_Position = vec4(0.5, 0.5, 0.0, 1.0);
    } else if(gl_VertexIndex == 2) {
        gl_Position = vec4(-0.5, 0.5, 0.0, 1.0);
    }
}
#version 450
#extension GL_ARB_separate_shader_objects : enable

layout(location = 0) out vec4 outColor;

void main() {
    outColor = vec4(1.0, 0.0, 0.0, 1.0);
}
cmake_minimum_required(VERSION 3.22)

project(vulkan-test)

set(CMAKE_CXX_STANDARD 17)

add_executable(app main.cpp)

find_package(Vulkan REQUIRED)
target_include_directories(app PRIVATE ${Vulkan_INCLUDE_DIRS})
target_link_libraries(app PRIVATE ${Vulkan_LIBRARIES})

find_package(glfw3 CONFIG REQUIRED)
target_link_libraries(app PRIVATE glfw)