Add the graphics api independent scenegraph port

Opt in via environment variables:
QSG_RHI=1 -> enable using QRhi instead of GL
QSG_RHI_BACKEND -> set to vulkan, metal, d3d11, gl to override the default
(the default is d3d11 on Windows, metal on Mac, gl elsewhere)

Or force a given rhi backend via the existing
QQuickWindow::setSceneGraphBackend().

Otherwise the default behavior is the same as before, the rhi code path
is never active by default.

-no-opengl builds are supported in the sense that they work and default
to the software backend. However, the rhi code path cannot currently be
used in such builds, even though QRhi from qtbase is fully functional
with Vulkan, D3D, or Metal even when qtbase was configured with
-no-opengl. This cannot be utilized by Quick atm due to OpenGL usage
being all over the place in the sources corresponding to the default
backend, and those host the rhi code path as well. This will be cleaned up
hopefully in Qt 6, with the removal all direct OpenGL usage.

Other env.vars.:
QSG_RHI_DEBUG_LAYER=1 -> enable D3D debug or Vulkan validation layer
(assuming the system is set up for this)
QSG_RHI_SHADEREFFECT_DEBUG=1 -> print stuff from ShaderEffect
QSG_SAMPLES=1,2,4,... -> MSAA sample count (but QSurfaceFormat works too)
QT_D3D_ADAPTER_INDEX=0,1,... -> D3D adapter index
QT_VK_PHYSICAL_DEVICE_INDEX=0,1,... -> Vulkan physical device index
QSG_RHI_UINT32_INDEX=1 -> always use uint index data (both
merged/unmerged, convert when needed - with some rhi backends this is
implicit)
QSG_RENDER_LOOP -> to override the render loop as usual. The default
with RHI is threaded for Metal, threaded for Vulkan on Windows, basic
for Vulkan on Linux and Android (to be checked later), while the existing
rules apply for OpenGL.

Not supported when running with QRhi:
  - particles
  - compressed atlases (though this is transparent to the apps)
  - QSGRenderNode
  - QQuickRenderControl
  - QQuickFramebufferObject
  - certain QQuickWindow functionality that depends directly on OpenGL
  - anisotropic filtering for textures
  - native text may lack some gamma correction
  - QSGEngine applicability unclear
  - some QML profiler logs may be incorrect or irrelevant

Change-Id: I7822e99ad79e342e4166275da6e9e66498d76521
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 567 insertions, 0 deletions

diff --git a/src/quick/scenegraph/qsgrhisupport.cpp b/src/quick/scenegraph/qsgrhisupport.cpp
new file mode 100644
index 0000000000..2ca66f23d5
--- /dev/null
+++ b/src/quick/scenegraph/qsgrhisupport.cpp
@@ -0,0 +1,567 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qsgrhisupport_p.h"
+#include "qsgdefaultrendercontext_p.h"
+#include <QtGui/qwindow.h>
+
+#if QT_CONFIG(vulkan)
+#include <QtGui/qvulkaninstance.h>
+#endif
+
+QT_BEGIN_NAMESPACE
+
+#if QT_CONFIG(vulkan)
+QVulkanInstance *s_vulkanInstance = nullptr;
+#endif
+
+QVulkanInstance *QSGRhiSupport::vulkanInstance()
+{
+#if QT_CONFIG(vulkan)
+    QSGRhiSupport *inst = QSGRhiSupport::instance();
+    if (!inst->isRhiEnabled() || inst->rhiBackend() != QRhi::Vulkan)
+        return nullptr;
+
+    if (!s_vulkanInstance) {
+        s_vulkanInstance = new QVulkanInstance;
+        if (inst->isDebugLayerRequested()) {
+#ifndef Q_OS_ANDROID
+            s_vulkanInstance->setLayers(QByteArrayList() << "VK_LAYER_LUNARG_standard_validation");
+#else
+            s_vulkanInstance->setLayers(QByteArrayList()
+                                        << "VK_LAYER_GOOGLE_threading"
+                                        << "VK_LAYER_LUNARG_parameter_validation"
+                                        << "VK_LAYER_LUNARG_object_tracker"
+                                        << "VK_LAYER_LUNARG_core_validation"
+                                        << "VK_LAYER_LUNARG_image"
+                                        << "VK_LAYER_LUNARG_swapchain"
+                                        << "VK_LAYER_GOOGLE_unique_objects");
+#endif
+        }
+        s_vulkanInstance->setExtensions(QByteArrayList()
+                                        << "VK_KHR_get_physical_device_properties2");
+        if (!s_vulkanInstance->create()) {
+            qWarning("Failed to create Vulkan instance");
+            delete s_vulkanInstance;
+            s_vulkanInstance = nullptr;
+        }
+    }
+    return s_vulkanInstance;
+#else
+    return nullptr;
+#endif
+}
+
+void QSGRhiSupport::cleanup()
+{
+#if QT_CONFIG(vulkan)
+    delete s_vulkanInstance;
+    s_vulkanInstance = nullptr;
+#endif
+}
+
+QSGRhiSupport::QSGRhiSupport()
+    : m_set(false),
+      m_enableRhi(false),
+      m_debugLayer(false),
+      m_profile(false),
+      m_shaderEffectDebug(false)
+{
+}
+
+void QSGRhiSupport::applySettings()
+{
+    m_set = true;
+
+    if (m_requested.valid) {
+        // explicit rhi backend request from C++ (e.g. via QQuickWindow)
+        m_enableRhi = m_requested.rhi;
+        switch (m_requested.api) {
+        case QSGRendererInterface::OpenGLRhi:
+            m_rhiBackend = QRhi::OpenGLES2;
+            break;
+        case QSGRendererInterface::Direct3D11Rhi:
+            m_rhiBackend = QRhi::D3D11;
+            break;
+        case QSGRendererInterface::VulkanRhi:
+            m_rhiBackend = QRhi::Vulkan;
+            break;
+        case QSGRendererInterface::MetalRhi:
+            m_rhiBackend = QRhi::Metal;
+            break;
+        case QSGRendererInterface::NullRhi:
+            m_rhiBackend = QRhi::Null;
+            break;
+        default:
+            Q_ASSERT_X(false, "QSGRhiSupport", "Internal error: unhandled GraphicsApi type");
+            break;
+        }
+    } else {
+        // check env.vars., fall back to platform-specific defaults when backend is not set
+        m_enableRhi = qEnvironmentVariableIntValue("QSG_RHI");
+        const QByteArray rhiBackend = qgetenv("QSG_RHI_BACKEND");
+        if (rhiBackend == QByteArrayLiteral("gl")
+                || rhiBackend == QByteArrayLiteral("gles2")
+                || rhiBackend == QByteArrayLiteral("opengl"))
+        {
+            m_rhiBackend = QRhi::OpenGLES2;
+        } else if (rhiBackend == QByteArrayLiteral("d3d11") || rhiBackend == QByteArrayLiteral("d3d")) {
+            m_rhiBackend = QRhi::D3D11;
+        } else if (rhiBackend == QByteArrayLiteral("vulkan")) {
+            m_rhiBackend = QRhi::Vulkan;
+        } else if (rhiBackend == QByteArrayLiteral("metal")) {
+            m_rhiBackend = QRhi::Metal;
+        } else if (rhiBackend == QByteArrayLiteral("null")) {
+            m_rhiBackend = QRhi::Null;
+        } else {
+#if defined(Q_OS_WIN)
+            m_rhiBackend = QRhi::D3D11;
+#elif defined(Q_OS_DARWIN)
+            m_rhiBackend = QRhi::Metal;
+#else
+            m_rhiBackend = QRhi::OpenGLES2;
+#endif
+            // Vulkan has to be requested explicitly
+        }
+    }
+
+    if (!m_enableRhi)
+        return;
+
+    // validation layers (Vulkan) or debug layer (D3D)
+    m_debugLayer = qEnvironmentVariableIntValue("QSG_RHI_DEBUG_LAYER");
+
+    // EnableProfiling + DebugMarkers
+    m_profile = qEnvironmentVariableIntValue("QSG_RHI_PROFILE");
+
+    m_shaderEffectDebug = qEnvironmentVariableIntValue("QSG_RHI_SHADEREFFECT_DEBUG");
+
+    const char *backendName = "unknown";
+    switch (m_rhiBackend) {
+    case QRhi::Null:
+        backendName = "Null";
+        break;
+    case QRhi::Vulkan:
+        backendName = "Vulkan";
+        break;
+    case QRhi::OpenGLES2:
+        backendName = "OpenGL";
+        break;
+    case QRhi::D3D11:
+        backendName = "D3D11";
+        break;
+    case QRhi::Metal:
+        backendName = "Metal";
+        break;
+    default:
+        break;
+    }
+    qDebug("Using QRhi with backend %s\n  graphics API debug/validation layers: %d\n  QRhi profiling and debug markers: %d",
+           backendName, m_debugLayer, m_profile);
+}
+
+QSGRhiSupport *QSGRhiSupport::staticInst()
+{
+    static QSGRhiSupport inst;
+    return &inst;
+}
+
+void QSGRhiSupport::configure(QSGRendererInterface::GraphicsApi api)
+{
+    Q_ASSERT(QSGRendererInterface::isApiRhiBased(api));
+    QSGRhiSupport *inst = staticInst();
+    if (inst->m_set) {
+        qWarning("QRhi is already configured, request ignored");
+        return;
+    }
+    inst->m_requested.valid = true;
+    inst->m_requested.api = api;
+    inst->m_requested.rhi = true;
+    inst->applySettings();
+}
+
+QSGRhiSupport *QSGRhiSupport::instance()
+{
+    QSGRhiSupport *inst = staticInst();
+    if (!inst->m_set)
+        inst->applySettings();
+    return inst;
+}
+
+QSGRendererInterface::GraphicsApi QSGRhiSupport::graphicsApi() const
+{
+    if (!m_enableRhi)
+        return QSGRendererInterface::OpenGL;
+
+    switch (m_rhiBackend) {
+    case QRhi::Null:
+        return QSGRendererInterface::NullRhi;
+    case QRhi::Vulkan:
+        return QSGRendererInterface::VulkanRhi;
+    case QRhi::OpenGLES2:
+        return QSGRendererInterface::OpenGLRhi;
+    case QRhi::D3D11:
+        return QSGRendererInterface::Direct3D11Rhi;
+    case QRhi::Metal:
+        return QSGRendererInterface::MetalRhi;
+    default:
+        return QSGRendererInterface::Unknown;
+    }
+}
+
+QSurface::SurfaceType QSGRhiSupport::windowSurfaceType() const
+{
+    if (!m_enableRhi)
+        return QSurface::OpenGLSurface;
+
+    switch (m_rhiBackend) {
+    case QRhi::Vulkan:
+        return QSurface::VulkanSurface;
+    case QRhi::OpenGLES2:
+        return QSurface::OpenGLSurface;
+    case QRhi::D3D11:
+        return QSurface::OpenGLSurface; // yup, OpenGLSurface
+    case QRhi::Metal:
+        return QSurface::MetalSurface;
+    default:
+        return QSurface::OpenGLSurface;
+    }
+}
+
+#if QT_CONFIG(vulkan)
+static const void *qsgrhi_vk_rifResource(QSGRendererInterface::Resource res, const QRhiNativeHandles *nat,
+                                   const QRhiNativeHandles *cbNat)
+{
+    const QRhiVulkanNativeHandles *vknat = static_cast<const QRhiVulkanNativeHandles *>(nat);
+    const QRhiVulkanCommandBufferNativeHandles *maybeVkCbNat =
+            static_cast<const QRhiVulkanCommandBufferNativeHandles *>(cbNat);
+
+    switch (res) {
+    case QSGRendererInterface::DeviceResource:
+        return &vknat->dev;
+    case QSGRendererInterface::CommandQueueResource:
+        return &vknat->gfxQueue;
+    case QSGRendererInterface::CommandListResource:
+        if (maybeVkCbNat)
+            return &maybeVkCbNat->commandBuffer;
+        else
+            return nullptr;
+    case QSGRendererInterface::PhysicalDeviceResource:
+        return &vknat->physDev;
+    default:
+        return nullptr;
+    }
+}
+#endif
+
+#if QT_CONFIG(opengl)
+static const void *qsgrhi_gl_rifResource(QSGRendererInterface::Resource res, const QRhiNativeHandles *nat)
+{
+    const QRhiGles2NativeHandles *glnat = static_cast<const QRhiGles2NativeHandles *>(nat);
+    switch (res) {
+    case QSGRendererInterface::OpenGLContextResource:
+        return glnat->context;
+    default:
+        return nullptr;
+    }
+}
+#endif
+
+#ifdef Q_OS_WIN
+static const void *qsgrhi_d3d11_rifResource(QSGRendererInterface::Resource res, const QRhiNativeHandles *nat)
+{
+    const QRhiD3D11NativeHandles *d3dnat = static_cast<const QRhiD3D11NativeHandles *>(nat);
+    switch (res) {
+    case QSGRendererInterface::DeviceResource:
+        return d3dnat->dev;
+    case QSGRendererInterface::DeviceContextResource:
+        return d3dnat->context;
+    default:
+        return nullptr;
+    }
+}
+#endif
+
+#ifdef Q_OS_DARWIN
+static const void *qsgrhi_mtl_rifResource(QSGRendererInterface::Resource res, const QRhiNativeHandles *nat,
+                                    const QRhiNativeHandles *cbNat)
+{
+    const QRhiMetalNativeHandles *mtlnat = static_cast<const QRhiMetalNativeHandles *>(nat);
+    const QRhiMetalCommandBufferNativeHandles *maybeMtlCbNat =
+            static_cast<const QRhiMetalCommandBufferNativeHandles *>(cbNat);
+
+    switch (res) {
+    case QSGRendererInterface::DeviceResource:
+        return mtlnat->dev;
+    case QSGRendererInterface::CommandQueueResource:
+        return mtlnat->cmdQueue;
+    case QSGRendererInterface::CommandListResource:
+        if (maybeMtlCbNat)
+            return maybeMtlCbNat->commandBuffer;
+        else
+            return nullptr;
+    case QSGRendererInterface::CommandEncoderResource:
+        if (maybeMtlCbNat)
+            return maybeMtlCbNat->encoder;
+        else
+            return nullptr;
+    default:
+        return nullptr;
+    }
+}
+#endif
+
+const void *QSGRhiSupport::rifResource(QSGRendererInterface::Resource res, const QSGDefaultRenderContext *rc)
+{
+    QRhi *rhi = rc->rhi();
+    if (res == QSGRendererInterface::RhiResource || !rhi)
+        return rhi;
+
+    const QRhiNativeHandles *nat = rhi->nativeHandles();
+    if (!nat)
+        return nullptr;
+
+    switch (m_rhiBackend) {
+#if QT_CONFIG(vulkan)
+    case QRhi::Vulkan:
+    {
+        QRhiCommandBuffer *cb = rc->currentFrameCommandBuffer();
+        return qsgrhi_vk_rifResource(res, nat, cb ? cb->nativeHandles() : nullptr);
+    }
+#endif
+#if QT_CONFIG(opengl)
+    case QRhi::OpenGLES2:
+        return qsgrhi_gl_rifResource(res, nat);
+#endif
+#ifdef Q_OS_WIN
+    case QRhi::D3D11:
+        return qsgrhi_d3d11_rifResource(res, nat);
+#endif
+#ifdef Q_OS_DARWIN
+    case QRhi::Metal:
+    {
+        QRhiCommandBuffer *cb = rc->currentFrameCommandBuffer();
+        return qsgrhi_mtl_rifResource(res, nat, cb ? cb->nativeHandles() : nullptr);
+    }
+#endif
+    default:
+        return nullptr;
+    }
+}
+
+int QSGRhiSupport::chooseSampleCountForWindowWithRhi(QWindow *window, QRhi *rhi)
+{
+    int msaaSampleCount = qMax(QSurfaceFormat::defaultFormat().samples(), window->requestedFormat().samples());
+    if (qEnvironmentVariableIsSet("QSG_SAMPLES"))
+        msaaSampleCount = qEnvironmentVariableIntValue("QSG_SAMPLES");
+    msaaSampleCount = qMax(1, msaaSampleCount);
+    if (msaaSampleCount > 1) {
+        const QVector<int> supportedSampleCounts = rhi->supportedSampleCounts();
+        if (!supportedSampleCounts.contains(msaaSampleCount)) {
+            int reducedSampleCount = 1;
+            for (int i = supportedSampleCounts.count() - 1; i >= 0; --i) {
+                if (supportedSampleCounts[i] <= msaaSampleCount) {
+                    reducedSampleCount = supportedSampleCounts[i];
+                    break;
+                }
+            }
+            qWarning() << "Requested MSAA sample count" << msaaSampleCount
+                       << "but supported sample counts are" << supportedSampleCounts
+                       << ", using sample count" << reducedSampleCount << "instead";
+            msaaSampleCount = reducedSampleCount;
+        }
+    }
+    return msaaSampleCount;
+}
+
+// must be called on the main thread
+QOffscreenSurface *QSGRhiSupport::maybeCreateOffscreenSurface(QWindow *window)
+{
+    QOffscreenSurface *offscreenSurface = nullptr;
+#if QT_CONFIG(opengl)
+    if (rhiBackend() == QRhi::OpenGLES2) {
+        const QSurfaceFormat format = window->requestedFormat();
+        offscreenSurface = QRhiGles2InitParams::newFallbackSurface(format);
+    }
+#else
+    Q_UNUSED(window);
+#endif
+    return offscreenSurface;
+}
+
+// must be called on the render thread
+QRhi *QSGRhiSupport::createRhi(QWindow *window, QOffscreenSurface *offscreenSurface)
+{
+    QRhi *rhi = nullptr;
+
+    QRhi::Flags flags = 0;
+    if (isProfilingRequested())
+        flags |= QRhi::EnableProfiling | QRhi::EnableDebugMarkers;
+
+    QRhi::Implementation backend = rhiBackend();
+    if (backend == QRhi::Null) {
+        QRhiNullInitParams rhiParams;
+        rhi = QRhi::create(backend, &rhiParams, flags);
+    }
+#if QT_CONFIG(opengl)
+    if (backend == QRhi::OpenGLES2) {
+        const QSurfaceFormat format = window->requestedFormat();
+        QRhiGles2InitParams rhiParams;
+        rhiParams.format = format;
+        rhiParams.fallbackSurface = offscreenSurface;
+        rhiParams.window = window;
+        rhi = QRhi::create(backend, &rhiParams, flags);
+    }
+#endif
+#if QT_CONFIG(vulkan)
+    if (backend == QRhi::Vulkan) {
+        QRhiVulkanInitParams rhiParams;
+        rhiParams.inst = window->vulkanInstance();
+        if (!rhiParams.inst)
+            qWarning("No QVulkanInstance set for QQuickWindow, this is wrong.");
+        rhiParams.window = window;
+        rhi = QRhi::create(backend, &rhiParams, flags);
+    }
+#endif
+#ifdef Q_OS_WIN
+    if (backend == QRhi::D3D11) {
+        QRhiD3D11InitParams rhiParams;
+        rhiParams.enableDebugLayer = isDebugLayerRequested();
+        rhi = QRhi::create(backend, &rhiParams, flags);
+    }
+#endif
+#ifdef Q_OS_DARWIN
+    if (backend == QRhi::Metal) {
+        QRhiMetalInitParams rhiParams;
+        rhi = QRhi::create(backend, &rhiParams, flags);
+    }
+#endif
+
+    if (!rhi)
+        qWarning("Failed to create RHI (backend %d)", backend);
+
+    return rhi;
+}
+
+QImage QSGRhiSupport::grabAndBlockInCurrentFrame(QRhi *rhi, QRhiSwapChain *swapchain)
+{
+    Q_ASSERT(rhi->isRecordingFrame());
+
+    QRhiReadbackResult result;
+    QRhiReadbackDescription readbackDesc; // read from swapchain backbuffer
+    QRhiResourceUpdateBatch *resourceUpdates = rhi->nextResourceUpdateBatch();
+    resourceUpdates->readBackTexture(readbackDesc, &result);
+
+    swapchain->currentFrameCommandBuffer()->resourceUpdate(resourceUpdates);
+    rhi->finish(); // make sure the readback has finished, stall the pipeline if needed
+
+    // May be RGBA or BGRA. Plus premultiplied alpha.
+    QImage::Format imageFormat;
+    if (result.format == QRhiTexture::BGRA8) {
+#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
+        imageFormat = QImage::Format_ARGB32_Premultiplied;
+#else
+        imageFormat = QImage::Format_RGBA8888_Premultiplied;
+        // ### and should swap too
+#endif
+    } else {
+        imageFormat = QImage::Format_RGBA8888_Premultiplied;
+    }
+
+    const uchar *p = reinterpret_cast<const uchar *>(result.data.constData());
+    const QImage img(p, result.pixelSize.width(), result.pixelSize.height(), imageFormat);
+
+    if (rhi->isYUpInFramebuffer())
+        return img.mirrored();
+
+    return img.copy();
+}
+
+QSGRhiProfileConnection *QSGRhiProfileConnection::instance()
+{
+    static QSGRhiProfileConnection inst;
+    return &inst;
+}
+
+void QSGRhiProfileConnection::initialize(QRhi *rhi)
+{
+#ifdef RHI_REMOTE_PROFILER
+    const QString profHost = qEnvironmentVariable("QSG_RHI_PROFILE_HOST");
+    if (!profHost.isEmpty()) {
+        int profPort = qEnvironmentVariableIntValue("QSG_RHI_PROFILE_PORT");
+        if (!profPort)
+            profPort = 30667;
+        qDebug("Sending RHI profiling output to %s:%d", qPrintable(profHost), profPort);
+        m_profConn.reset(new QTcpSocket);
+        QObject::connect(m_profConn.data(), QOverload<QAbstractSocket::SocketError>::of(&QAbstractSocket::error), m_profConn.data(),
+                         [this](QAbstractSocket::SocketError socketError) { qDebug("  RHI profiler error: %d (%s)",
+                                                                                   socketError, qPrintable(m_profConn->errorString())); });
+        m_profConn->connectToHost(profHost, profPort);
+        m_profConn->waitForConnected(); // blocking wait because we want to send stuff already from the init below
+        rhi->profiler()->setDevice(m_profConn.data());
+        m_lastMemStatWrite.start();
+    }
+#else
+    Q_UNUSED(rhi);
+#endif
+}
+
+void QSGRhiProfileConnection::cleanup()
+{
+#ifdef RHI_REMOTE_PROFILER
+    m_profConn.reset();
+#endif
+}
+
+void QSGRhiProfileConnection::send(QRhi *rhi)
+{
+#ifdef RHI_REMOTE_PROFILER
+    if (m_profConn) {
+        // do this every 5 sec at most
+        if (m_lastMemStatWrite.elapsed() >= 5000) {
+            rhi->profiler()->addVMemAllocatorStats();
+            m_lastMemStatWrite.restart();
+        }
+    }
+#else
+    Q_UNUSED(rhi);
+#endif
+}
+
+QT_END_NAMESPACE