Introduce the Qt graphics abstraction as private QtGui helpers

Comes with backends for Vulkan, Metal, Direct3D 11.1, and OpenGL (ES).

All APIs are private for now.

Shader conditioning (i.e. generating a QRhiShader in memory or on disk
from some shader source code) is done via the tools and APIs provided
by qt-labs/qtshadertools.

The OpenGL support follows the cross-platform tradition of requiring
ES 2.0 only, while optionally using some (ES) 3.x features. It can
operate in core profile contexts as well.

Task-number: QTBUG-70287
Change-Id: I246f2e36d562e404012c05db2aa72487108aa7cc
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
 
 
 
 
 

1 files changed, 554 insertions, 0 deletions

diff --git a/tests/manual/rhi/hellominimalcrossgfxtriangle/hellominimalcrossgfxtriangle.cpp b/tests/manual/rhi/hellominimalcrossgfxtriangle/hellominimalcrossgfxtriangle.cpp
new file mode 100644
index 0000000000..a24b980173
--- /dev/null
+++ b/tests/manual/rhi/hellominimalcrossgfxtriangle/hellominimalcrossgfxtriangle.cpp
@@ -0,0 +1,554 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+// This is a compact, minimal, single-file demo of deciding the backend at
+// runtime while using the exact same shaders and rendering code without any
+// branching whatsoever once the QWindow is up and the RHI is initialized.
+
+#include <QGuiApplication>
+#include <QCommandLineParser>
+#include <QWindow>
+#include <QPlatformSurfaceEvent>
+#include <QElapsedTimer>
+
+#include <QtGui/private/qshader_p.h>
+#include <QFile>
+
+#include <QtGui/private/qrhinull_p.h>
+
+#ifndef QT_NO_OPENGL
+#include <QtGui/private/qrhigles2_p.h>
+#include <QOffscreenSurface>
+#endif
+
+#if QT_CONFIG(vulkan)
+#include <QLoggingCategory>
+#include <QtGui/private/qrhivulkan_p.h>
+#endif
+
+#ifdef Q_OS_WIN
+#include <QtGui/private/qrhid3d11_p.h>
+#endif
+
+#ifdef Q_OS_DARWIN
+#include <QtGui/private/qrhimetal_p.h>
+#endif
+
+static float vertexData[] = {
+    // Y up (note clipSpaceCorrMatrix in m_proj), CCW
+     0.0f,   0.5f,   1.0f, 0.0f, 0.0f,
+    -0.5f,  -0.5f,   0.0f, 1.0f, 0.0f,
+     0.5f,  -0.5f,   0.0f, 0.0f, 1.0f,
+};
+
+static QShader getShader(const QString &name)
+{
+    QFile f(name);
+    if (f.open(QIODevice::ReadOnly))
+        return QShader::fromSerialized(f.readAll());
+
+    return QShader();
+}
+
+enum GraphicsApi
+{
+    OpenGL,
+    Vulkan,
+    D3D11,
+    Metal,
+    Null
+};
+
+static GraphicsApi graphicsApi;
+
+static QString graphicsApiName()
+{
+    switch (graphicsApi) {
+    case OpenGL:
+        return QLatin1String("OpenGL 2.x");
+    case Vulkan:
+        return QLatin1String("Vulkan");
+    case D3D11:
+        return QLatin1String("Direct3D 11");
+    case Metal:
+        return QLatin1String("Metal");
+    case Null:
+        return QLatin1String("Null");
+    default:
+        break;
+    }
+    return QString();
+}
+
+class Window : public QWindow
+{
+public:
+    Window();
+    ~Window();
+
+    void init();
+    void releaseResources();
+    void resizeSwapChain();
+    void releaseSwapChain();
+    void render();
+
+    void exposeEvent(QExposeEvent *) override;
+    bool event(QEvent *) override;
+
+private:
+    bool m_running = false;
+    bool m_notExposed = false;
+    bool m_newlyExposed = false;
+
+    QRhi *m_r = nullptr;
+    bool m_hasSwapChain = false;
+    QRhiSwapChain *m_sc = nullptr;
+    QRhiRenderBuffer *m_ds = nullptr;
+    QRhiRenderPassDescriptor *m_rp = nullptr;
+    QRhiBuffer *m_vbuf = nullptr;
+    bool m_vbufReady = false;
+    QRhiBuffer *m_ubuf = nullptr;
+    QRhiShaderResourceBindings *m_srb = nullptr;
+    QRhiGraphicsPipeline *m_ps = nullptr;
+    QVector<QRhiResource *> releasePool;
+
+    QMatrix4x4 m_proj;
+    float m_rotation = 0;
+    float m_opacity = 1;
+    int m_opacityDir = -1;
+
+    QElapsedTimer m_timer;
+    qint64 m_elapsedMs;
+    int m_elapsedCount;
+
+#ifndef QT_NO_OPENGL
+    QOffscreenSurface *m_fallbackSurface = nullptr;
+#endif
+};
+
+Window::Window()
+{
+    // Tell the platform plugin what we want.
+    switch (graphicsApi) {
+    case OpenGL:
+#if QT_CONFIG(opengl)
+        setSurfaceType(OpenGLSurface);
+        setFormat(QRhiGles2InitParams::adjustedFormat());
+#endif
+        break;
+    case Vulkan:
+        setSurfaceType(VulkanSurface);
+        break;
+    case D3D11:
+        setSurfaceType(OpenGLSurface); // not a typo
+        break;
+    case Metal:
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 12, 0))
+        setSurfaceType(MetalSurface);
+#endif
+        break;
+    default:
+        break;
+    }
+}
+
+Window::~Window()
+{
+    releaseResources();
+}
+
+void Window::exposeEvent(QExposeEvent *)
+{
+    // initialize and start rendering when the window becomes usable for graphics purposes
+    if (isExposed() && !m_running) {
+        m_running = true;
+        init();
+        resizeSwapChain();
+    }
+
+    // stop pushing frames when not exposed (or size is 0)
+    if ((!isExposed() || (m_hasSwapChain && m_sc->surfacePixelSize().isEmpty())) && m_running)
+        m_notExposed = true;
+
+    // continue when exposed again and the surface has a valid size.
+    // note that the surface size can be (0, 0) even though size() reports a valid one...
+    if (isExposed() && m_running && m_notExposed && !m_sc->surfacePixelSize().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() && !m_sc->surfacePixelSize().isEmpty())
+        render();
+}
+
+bool Window::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 Window::init()
+{
+    if (graphicsApi == Null) {
+        QRhiNullInitParams params;
+        m_r = QRhi::create(QRhi::Null, &params);
+    }
+
+#ifndef QT_NO_OPENGL
+    if (graphicsApi == OpenGL) {
+        m_fallbackSurface = QRhiGles2InitParams::newFallbackSurface();
+        QRhiGles2InitParams params;
+        params.fallbackSurface = m_fallbackSurface;
+        params.window = this;
+        m_r = QRhi::create(QRhi::OpenGLES2, &params);
+    }
+#endif
+
+#if QT_CONFIG(vulkan)
+    if (graphicsApi == Vulkan) {
+        QRhiVulkanInitParams params;
+        params.inst = vulkanInstance();
+        params.window = this;
+        m_r = QRhi::create(QRhi::Vulkan, &params);
+    }
+#endif
+
+#ifdef Q_OS_WIN
+    if (graphicsApi == D3D11) {
+        QRhiD3D11InitParams params;
+        m_r = QRhi::create(QRhi::D3D11, &params);
+    }
+#endif
+
+#ifdef Q_OS_DARWIN
+    if (graphicsApi == Metal) {
+        QRhiMetalInitParams params;
+        m_r = QRhi::create(QRhi::Metal, &params);
+    }
+#endif
+
+    if (!m_r)
+        qFatal("Failed to create RHI backend");
+
+    // now onto the backend-independent init
+
+    m_sc = m_r->newSwapChain();
+    // allow depth-stencil, although we do not actually enable depth test/write for the triangle
+    m_ds = m_r->newRenderBuffer(QRhiRenderBuffer::DepthStencil,
+                                QSize(), // no need to set the size yet
+                                1,
+                                QRhiRenderBuffer::UsedWithSwapChainOnly);
+    releasePool << m_ds;
+    m_sc->setWindow(this);
+    m_sc->setDepthStencil(m_ds);
+    m_rp = m_sc->newCompatibleRenderPassDescriptor();
+    releasePool << m_rp;
+    m_sc->setRenderPassDescriptor(m_rp);
+
+    m_vbuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(vertexData));
+    releasePool << m_vbuf;
+    m_vbuf->build();
+    m_vbufReady = false;
+
+    m_ubuf = m_r->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 68);
+    releasePool << m_ubuf;
+    m_ubuf->build();
+
+    m_srb = m_r->newShaderResourceBindings();
+    releasePool << m_srb;
+    m_srb->setBindings({
+        QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage, m_ubuf)
+    });
+    m_srb->build();
+
+    m_ps = m_r->newGraphicsPipeline();
+    releasePool << m_ps;
+
+    QRhiGraphicsPipeline::TargetBlend premulAlphaBlend;
+    premulAlphaBlend.enable = true;
+    m_ps->setTargetBlends({ premulAlphaBlend });
+
+    const QShader vs = getShader(QLatin1String(":/color.vert.qsb"));
+    if (!vs.isValid())
+        qFatal("Failed to load shader pack (vertex)");
+    const QShader fs = getShader(QLatin1String(":/color.frag.qsb"));
+    if (!fs.isValid())
+        qFatal("Failed to load shader pack (fragment)");
+
+    m_ps->setShaderStages({
+        { QRhiGraphicsShaderStage::Vertex, vs },
+        { QRhiGraphicsShaderStage::Fragment, fs }
+    });
+
+    QRhiVertexInputLayout inputLayout;
+    inputLayout.setBindings({
+        { 5 * sizeof(float) }
+    });
+    inputLayout.setAttributes({
+        { 0, 0, QRhiVertexInputAttribute::Float2, 0 },
+        { 0, 1, QRhiVertexInputAttribute::Float3, 2 * sizeof(float) }
+    });
+
+    m_ps->setVertexInputLayout(inputLayout);
+    m_ps->setShaderResourceBindings(m_srb);
+    m_ps->setRenderPassDescriptor(m_rp);
+
+    m_ps->build();
+}
+
+void Window::releaseResources()
+{
+    qDeleteAll(releasePool);
+    releasePool.clear();
+
+    delete m_sc; // native swapchain is likely released already
+    m_sc = nullptr;
+
+    delete m_r;
+
+#ifndef QT_NO_OPENGL
+    delete m_fallbackSurface;
+#endif
+}
+
+void Window::resizeSwapChain()
+{
+    const QSize outputSize = m_sc->surfacePixelSize();
+
+    m_ds->setPixelSize(outputSize);
+    m_ds->build(); // == m_ds->release(); m_ds->build();
+
+    m_hasSwapChain = m_sc->buildOrResize();
+
+    m_elapsedMs = 0;
+    m_elapsedCount = 0;
+
+    m_proj = m_r->clipSpaceCorrMatrix();
+    m_proj.perspective(45.0f, outputSize.width() / (float) outputSize.height(), 0.01f, 100.0f);
+    m_proj.translate(0, 0, -4);
+}
+
+void Window::releaseSwapChain()
+{
+    if (m_hasSwapChain) {
+        m_hasSwapChain = false;
+        m_sc->release();
+    }
+}
+
+void Window::render()
+{
+    if (!m_hasSwapChain || m_notExposed)
+        return;
+
+    // If the window got resized or got newly exposed, resize the swapchain.
+    // (the newly-exposed case is not actually required by some
+    // platforms/backends, but f.ex. Vulkan on Windows seems to need it)
+    if (m_sc->currentPixelSize() != m_sc->surfacePixelSize() || m_newlyExposed) {
+        resizeSwapChain();
+        if (!m_hasSwapChain)
+            return;
+        m_newlyExposed = false;
+    }
+
+    // Start a new frame. This is where we block when too far ahead of
+    // GPU/present, and that's what throttles the thread to the refresh rate.
+    // (except for OpenGL where it happens either in endFrame or somewhere else
+    // depending on the GL implementation)
+    QRhi::FrameOpResult r = m_r->beginFrame(m_sc);
+    if (r == QRhi::FrameOpSwapChainOutOfDate) {
+        resizeSwapChain();
+        if (!m_hasSwapChain)
+            return;
+        r = m_r->beginFrame(m_sc);
+    }
+    if (r != QRhi::FrameOpSuccess) {
+        requestUpdate();
+        return;
+    }
+
+    if (m_elapsedCount)
+        m_elapsedMs += m_timer.elapsed();
+    m_timer.restart();
+    m_elapsedCount += 1;
+    if (m_elapsedMs >= 4000) {
+        qDebug("%f", m_elapsedCount / 4.0f);
+        m_elapsedMs = 0;
+        m_elapsedCount = 0;
+    }
+
+    // Set up buffer updates.
+    QRhiResourceUpdateBatch *u = m_r->nextResourceUpdateBatch();
+    if (!m_vbufReady) {
+        m_vbufReady = true;
+        u->uploadStaticBuffer(m_vbuf, vertexData);
+    }
+    m_rotation += 1.0f;
+    QMatrix4x4 mvp = m_proj;
+    mvp.rotate(m_rotation, 0, 1, 0);
+    u->updateDynamicBuffer(m_ubuf, 0, 64, mvp.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);
+    }
+    u->updateDynamicBuffer(m_ubuf, 64, 4, &m_opacity);
+
+    QRhiCommandBuffer *cb = m_sc->currentFrameCommandBuffer();
+    const QSize outputSizeInPixels = m_sc->currentPixelSize();
+
+    // Apply buffer updates, clear, start the renderpass (where applicable).
+    cb->beginPass(m_sc->currentFrameRenderTarget(), QColor::fromRgbF(0.4f, 0.7f, 0.0f, 1.0f), { 1.0f, 0 }, u);
+
+    cb->setGraphicsPipeline(m_ps);
+    cb->setViewport({ 0, 0, float(outputSizeInPixels.width()), float(outputSizeInPixels.height()) });
+    cb->setShaderResources();
+
+    const QRhiCommandBuffer::VertexInput vbufBinding(m_vbuf, 0);
+    cb->setVertexInput(0, 1, &vbufBinding);
+    cb->draw(3);
+
+    cb->endPass();
+
+    // Submit.
+    m_r->endFrame(m_sc);
+
+    requestUpdate(); // render continuously, throttled by the presentation rate (due to beginFrame above)
+}
+
+int main(int argc, char **argv)
+{
+    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+    QGuiApplication app(argc, argv);
+
+    // Defaults.
+#if defined(Q_OS_WIN)
+    graphicsApi = D3D11;
+#elif defined(Q_OS_DARWIN)
+    graphicsApi = Metal;
+#elif QT_CONFIG(vulkan)
+    graphicsApi = Vulkan;
+#else
+    graphicsApi = OpenGL;
+#endif
+
+    // Allow overriding via the command line.
+    QCommandLineParser cmdLineParser;
+    cmdLineParser.addHelpOption();
+    QCommandLineOption glOption({ "g", "opengl" }, QLatin1String("OpenGL (2.x)"));
+    cmdLineParser.addOption(glOption);
+    QCommandLineOption vkOption({ "v", "vulkan" }, QLatin1String("Vulkan"));
+    cmdLineParser.addOption(vkOption);
+    QCommandLineOption d3dOption({ "d", "d3d11" }, QLatin1String("Direct3D 11"));
+    cmdLineParser.addOption(d3dOption);
+    QCommandLineOption mtlOption({ "m", "metal" }, QLatin1String("Metal"));
+    cmdLineParser.addOption(mtlOption);
+    QCommandLineOption nullOption({ "n", "null" }, QLatin1String("Null"));
+    cmdLineParser.addOption(nullOption);
+    cmdLineParser.process(app);
+    if (cmdLineParser.isSet(glOption))
+        graphicsApi = OpenGL;
+    if (cmdLineParser.isSet(vkOption))
+        graphicsApi = Vulkan;
+    if (cmdLineParser.isSet(d3dOption))
+        graphicsApi = D3D11;
+    if (cmdLineParser.isSet(mtlOption))
+        graphicsApi = Metal;
+    if (cmdLineParser.isSet(nullOption))
+        graphicsApi = Null;
+
+    // Vulkan setup.
+#if QT_CONFIG(vulkan)
+    QVulkanInstance inst;
+    if (graphicsApi == Vulkan) {
+        if (!inst.create()) {
+            qWarning("Failed to create Vulkan instance, switching to OpenGL");
+            graphicsApi = OpenGL;
+        }
+    }
+#endif
+
+    // Create and show the window.
+    Window w;
+#if QT_CONFIG(vulkan)
+    if (graphicsApi == Vulkan)
+        w.setVulkanInstance(&inst);
+#endif
+    w.resize(1280, 720);
+    w.setTitle(graphicsApiName());
+    w.show();
+
+    // Window::event() will not get invoked when the
+    // PlatformSurfaceAboutToBeDestroyed event is sent during the QWindow
+    // destruction. That happens only when exiting via app::quit() instead of
+    // the more common QWindow::close(). Take care of it: if the
+    // QPlatformWindow is still around (there was no close() yet), get rid of
+    // the swapchain while it's not too late.
+    if (w.handle())
+        w.releaseSwapChain();
+
+    return app.exec();
+}