RHI ウィンドウの例

   // OpenGLの場合、ウィンドウに深度バッファおよびステンシルバッファが確実に用意されるようにするため。
    // 他のAPIでは、これはアプリケーション側で制御される（QRhiRenderBufferなど） 
    // ため、それらのAPIでは特別な設定は必要ありません。
    QSurfaceFormat fmt;
    fmt.setDepthBufferSize(24);
    fmt.setStencilBufferSize(8);
   // macOS での OpenGL 利用を可能にするための特例。
    // （ただし、デフォルトの Metal を使用することが推奨されます）
    // gl_VertexID は GLSL 130 の機能であるため、 macOS で得られる デフォルトの OpenGL 2.1 コンテキスト 
    // では不十分です。
#ifdef Q_OS_MACOS
    fmt.setVersion(4, 1);
    fmt.setProfile(QSurfaceFormat::CoreProfile);
#endif
    QSurfaceFormat::setDefaultFormat(fmt);

    // Vulkan用。
#if QT_CONFIG(vulkan)
    QVulkanInstance inst;
    if(graphicsApi==QRhi::Vulkan) {
        // 利用可能な場合は検証をリクエストします。これは完全に任意であり
        // パフォーマンスに影響を与えるため、本番環境での使用は避けるべきです。
        inst.setLayers({"VK_LAYER_KHRONOS_validation"});
        // QRhiとの互換性を確保する。
        inst.setExtensions(QRhiVulkanInitParams::preferredInstanceExtensions());
        if(!inst.create()) {
            qWarning("Failed to create Vulkan instance, switching to OpenGL");
            graphicsApi=QRhi::OpenGLES2;
        }
    }
#endif

RhiWindow::RhiWindow(QRhi::Implementation graphicsApi)
    : m_graphicsApi(graphicsApi)
{
    switch (graphicsApi) {
    case QRhi::OpenGLES2:
        setSurfaceType(OpenGLSurface);
        break;
    case QRhi::Vulkan:
        setSurfaceType(VulkanSurface);
        break;
    case QRhi::D3D11:
    case QRhi::D3D12:
        setSurfaceType(Direct3DSurface);
        break;
    case QRhi::Metal:
        setSurfaceType(MetalSurface);
        break;
    case QRhi::Null:
        break; // RasterSurface
    }
}

voidRhiWindow::init()
{
    if(m_graphicsApi==QRhi::Null) {
        QRhiNullInitParams params;
        m_rhi.reset(QRhi::create(QRhi::Null, &params));
    }

#if QT_CONFIG(opengl)
    if(m_graphicsApi==QRhi::OpenGLES2) {
        m_fallbackSurface.reset(QRhiGles2InitParams::newFallbackSurface());
        QRhiGles2InitParams params;
        params.fallbackSurface=m_fallbackSurface.get();
        params.window= this;
        m_rhi.reset(QRhi::create(QRhi::OpenGLES2, &params));
    }
#endif

#if QT_CONFIG(vulkan)
    if(m_graphicsApi==QRhi::Vulkan) {
        QRhiVulkanInitParams params;
        params.inst=vulkanInstance();
        params.window= this;
        m_rhi.reset(QRhi::create(QRhi::Vulkan, &params));
    }
#endif

#ifdef Q_OS_WIN
    if(m_graphicsApi==QRhi::D3D11) {
        QRhiD3D11InitParams params;
        // 利用可能な場合は、デバッグレイヤーを有効にします。これはオプションであり 、
        // 本番ビルドでは避けるべきです。
        params.enableDebugLayer= true;
        m_rhi.reset(QRhi::create(QRhi::D3D11, &params));
    }else if(m_graphicsApi==QRhi::D3D12) {
        QRhiD3D12InitParams params;
        // 利用可能な場合は、デバッグレイヤーを有効にします。これはオプションであり 、
        // 本番ビルドでは避けるべきです。
        params.enableDebugLayer= true;
        m_rhi.reset(QRhi::create(QRhi::D3D12, &params));
    }
#endif

#if QT_CONFIG(metal)
    if(m_graphicsApi==QRhi::Metal) {
        QRhiMetalInitParams params;
        m_rhi.reset(QRhi::create(QRhi::Metal, &params));
    }
#endif

    if(!m_rhi)
        qFatal("Failed to create RHI backend");

void RhiWindow::exposeEvent(QExposeEvent *)
{
    // initialize and start rendering when the window becomes usable for graphics purposes
    if (isExposed() && !m_initialized) {
        init();
        resizeSwapChain();
        m_initialized = true;
    }

    const QSize surfaceSize = m_hasSwapChain ? m_sc->surfacePixelSize() : QSize();

    // stop pushing frames when not exposed (or size is 0)
    if ((!isExposed() || (m_hasSwapChain && surfaceSize.isEmpty())) && m_initialized && !m_notExposed)
        m_notExposed = true;

    // Continue when exposed again and the surface has a valid size. Note that
    // surfaceSize can be (0, 0) even though size() reports a valid one, hence
    // trusting surfacePixelSize() and not QWindow.
    if (isExposed() && m_initialized && m_notExposed && !surfaceSize.isEmpty()) {
        m_notExposed = false;
        m_newlyExposed = true;
    }

    // always render a frame on exposeEvent() (when exposed) in order to update
    // immediately on window resize.
    if (isExposed() && !surfaceSize.isEmpty())
        render();
}

void RhiWindow::render()
{
    if (!m_hasSwapChain || m_notExposed)
        return;

    std::unique_ptr<QRhiSwapChain> m_sc;
    std::unique_ptr<QRhiRenderBuffer> m_ds;
    std::unique_ptr<QRhiRenderPassDescriptor> m_rp;

    m_sc.reset(m_rhi->newSwapChain());
    m_ds.reset(m_rhi->newRenderBuffer(QRhiRenderBuffer::DepthStencil,
                                      QSize(), // no need to set the size here, due to UsedWithSwapChainOnly
                                      1,
                                      QRhiRenderBuffer::UsedWithSwapChainOnly));
    m_sc->setWindow(this);
    m_sc->setDepthStencil(m_ds.get());
    m_rp.reset(m_sc->newCompatibleRenderPassDescriptor());
    m_sc->setRenderPassDescriptor(m_rp.get());

void RhiWindow::resizeSwapChain()
{
    m_hasSwapChain = m_sc->createOrResize(); // also handles m_ds

    const QSize outputSize = m_sc->currentPixelSize();
    m_viewProjection = m_rhi->clipSpaceCorrMatrix();
    m_viewProjection.perspective(45.0f, outputSize.width() / (float) outputSize.height(), 0.01f, 1000.0f);
    m_viewProjection.translate(0, 0, -4);
}

    // If the window got resized or newly exposed, resize the swapchain. (the
    // newly-exposed case is not actually required by some platforms, but is
    // here for robustness and portability)
    //
    // This (exposeEvent + the logic here) is the only safe way to perform
    // resize handling. Note the usage of the RHI's surfacePixelSize(), and
    // never QWindow::size(). (the two may or may not be the same under the hood,
    // depending on the backend and platform)
    //
    if (m_sc->currentPixelSize() != m_sc->surfacePixelSize() || m_newlyExposed) {
        resizeSwapChain();
        if (!m_hasSwapChain)
            return;
        m_newlyExposed = false;
    }

    m_rhi->endFrame(m_sc.get());

    // Always request the next frame via requestUpdate(). On some platforms this is backed
    // by a platform-specific solution, e.g. CVDisplayLink on macOS, which is potentially
    // more efficient than a timer, queued metacalls, etc.
    requestUpdate();
}

bool RhiWindow::event(QEvent *e)
{
    switch (e->type()) {
    case QEvent::UpdateRequest:
        render();
        break;

    case QEvent::PlatformSurface:
        // this is the proper time to tear down the swapchain (while the native window and surface are still around)
        if (static_cast<QPlatformSurfaceEvent *>(e)->surfaceEventType() == QPlatformSurfaceEvent::SurfaceAboutToBeDestroyed)
            releaseSwapChain();
        break;

    default:
        break;
    }

    return QWindow::event(e);
}

void HelloWindow::customInit()
{
    m_initialUpdates = m_rhi->nextResourceUpdateBatch();

    m_vbuf.reset(m_rhi->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(vertexData)));
    m_vbuf->create();
    m_initialUpdates->uploadStaticBuffer(m_vbuf.get(), vertexData);

    static const quint32 UBUF_SIZE = 68;
    m_ubuf.reset(m_rhi->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, UBUF_SIZE));
    m_ubuf->create();

   m_colorTriSrb.reset(m_rhi->newShaderResourceBindings());
   static const QRhiShaderResourceBinding::StageFlags visibility =
           QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage;
   m_colorTriSrb->setBindings({
           QRhiShaderResourceBinding::uniformBuffer(0, visibility, m_ubuf.get())
   });
   m_colorTriSrb->create();

   m_colorPipeline.reset(m_rhi->newGraphicsPipeline());
   // Enable depth testing; not quite needed for a simple triangle, but we
   // have a depth-stencil buffer so why not.
   m_colorPipeline->setDepthTest(true);
   m_colorPipeline->setDepthWrite(true);
   // Blend factors default to One, OneOneMinusSrcAlpha, which is convenient.
   QRhiGraphicsPipeline::TargetBlend premulAlphaBlend;
   premulAlphaBlend.enable = true;
   m_colorPipeline->setTargetBlends({ premulAlphaBlend });
   m_colorPipeline->setShaderStages({
       { QRhiShaderStage::Vertex, getShader(QLatin1String(":/color.vert.qsb")) },
       { QRhiShaderStage::Fragment, getShader(QLatin1String(":/color.frag.qsb")) }
   });
   QRhiVertexInputLayout inputLayout;
   inputLayout.setBindings({
       { 5 * sizeof(float) }
   });
   inputLayout.setAttributes({
       { 0, 0, QRhiVertexInputAttribute::Float2, 0 },
       { 0, 1, QRhiVertexInputAttribute::Float3, 2 * sizeof(float) }
   });
   m_colorPipeline->setVertexInputLayout(inputLayout);
   m_colorPipeline->setShaderResourceBindings(m_colorTriSrb.get());
   m_colorPipeline->setRenderPassDescriptor(m_rp.get());
   m_colorPipeline->create();

static QShader getShader(const QString &name)
{
    QFile f(name);
    if (f.open(QIODevice::ReadOnly))
        return QShader::fromSerialized(f.readAll());

    return QShader();
}

layout(location = 0) in vec4 position;
layout(location = 1) in vec3 color;

    QRhi::FrameOpResult result= m_rhi->beginFrame(m_sc.get());
    if(result==QRhi::FrameOpSwapChainOutOfDate) {
        resizeSwapChain();
        if(!m_hasSwapChain)
            return;
        result= m_rhi->beginFrame(m_sc.get());
    }
    if(result!=QRhi::FrameOpSuccess) {
        qWarning("beginFrame failed with %d, will retry", result);
        requestUpdate();
        return;
    }

    customRender();

void HelloWindow::customRender()
{
    QRhiResourceUpdateBatch *resourceUpdates = m_rhi->nextResourceUpdateBatch();

    if (m_initialUpdates) {
        resourceUpdates->merge(m_initialUpdates);
        m_initialUpdates->release();
        m_initialUpdates = nullptr;
    }

    m_rotation += 1.0f;
    QMatrix4x4 modelViewProjection = m_viewProjection;
    modelViewProjection.rotate(m_rotation, 0, 1, 0);
    resourceUpdates->updateDynamicBuffer(m_ubuf.get(), 0, 64, modelViewProjection.constData());
    m_opacity += m_opacityDir * 0.005f;
    if (m_opacity < 0.0f || m_opacity > 1.0f) {
        m_opacityDir *= -1;
        m_opacity = qBound(0.0f, m_opacity, 1.0f);
    }
    resourceUpdates->updateDynamicBuffer(m_ubuf.get(), 64, 4, &m_opacity);

    QRhiCommandBuffer *cb = m_sc->currentFrameCommandBuffer();
    const QSize outputSizeInPixels = m_sc->currentPixelSize();

    cb->beginPass(m_sc->currentFrameRenderTarget(), Qt::black, { 1.0f, 0 }, resourceUpdates);

    cb->setGraphicsPipeline(m_colorPipeline.get());
    cb->setShaderResources();
    const QRhiCommandBuffer::VertexInput vbufBinding(m_vbuf.get(), 0);
    cb->setVertexInput(0, 1, &vbufBinding);
    cb->draw(3);

    cb->endPass();

void HelloWindow::ensureFullscreenTexture(const QSize &pixelSize, QRhiResourceUpdateBatch *u)
{
    if (m_texture && m_texture->pixelSize() == pixelSize)
        return;

    if (!m_texture)
        m_texture.reset(m_rhi->newTexture(QRhiTexture::RGBA8, pixelSize));
    else
        m_texture->setPixelSize(pixelSize);

    m_texture->create();

    QImage image(pixelSize, QImage::Format_RGBA8888_Premultiplied);
    image.setDevicePixelRatio(devicePixelRatio());

    u->uploadTexture(m_texture.get(), image);