1 files changed, 128 insertions, 0 deletions
diff --git a/tests/manual/graphicsframecapture/main.cpp b/tests/manual/graphicsframecapture/main.cpp
new file mode 100644
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+++ b/tests/manual/graphicsframecapture/main.cpp
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+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
+
+// This is a compact, minimal 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 "examplewindow.h"
+
+
+QString graphicsApiName(QRhi::Implementation graphicsApi);
+QRhi::Implementation graphicsApiFromCmd(const QGuiApplication &app);
+
+int main(int argc, char **argv)
+{
+    QGuiApplication app(argc, argv);
+    QRhi::Implementation graphicsApi = graphicsApiFromCmd(app);
+
+    QSurfaceFormat fmt;
+    fmt.setDepthBufferSize(24);
+    fmt.setStencilBufferSize(8);
+    QSurfaceFormat::setDefaultFormat(fmt);
+
+    ExampleWindow w(graphicsApi);
+
+#if QT_CONFIG(vulkan)
+    QVulkanInstance inst;
+    if (graphicsApi == QRhi::Vulkan) {
+        inst.setLayers({ "VK_LAYER_KHRONOS_validation" });
+        inst.setExtensions(QRhiVulkanInitParams::preferredInstanceExtensions());
+        if (!inst.create()) {
+            qWarning("Failed to create Vulkan instance, switching to OpenGL");
+            graphicsApi = QRhi::OpenGLES2;
+        }
+    }
+#endif
+
+#if QT_CONFIG(vulkan)
+    if (graphicsApi == QRhi::Vulkan)
+        w.setVulkanInstance(&inst);
+#endif
+    w.resize(1280, 720);
+    w.setTitle(QCoreApplication::applicationName() + QLatin1String(" - ") + graphicsApiName(graphicsApi));
+    w.show();
+
+    int ret = app.exec();
+
+    // 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 ret;
+}
+
+QString graphicsApiName(QRhi::Implementation graphicsApi)
+{
+    switch (graphicsApi) {
+    case QRhi::Null:
+        return QLatin1String("Null (no output)");
+    case QRhi::OpenGLES2:
+        return QLatin1String("OpenGL 2.x");
+    case QRhi::Vulkan:
+        return QLatin1String("Vulkan");
+    case QRhi::D3D11:
+        return QLatin1String("Direct3D 11");
+    case QRhi::D3D12:
+        return QLatin1String("Direct3D 12");
+    case QRhi::Metal:
+        return QLatin1String("Metal");
+    default:
+        break;
+    }
+    return QString();
+}
+
+QRhi::Implementation graphicsApiFromCmd(const QGuiApplication &app) {
+    QRhi::Implementation graphicsApi;
+#if defined(Q_OS_WIN)
+    graphicsApi = QRhi::D3D11;
+#elif QT_CONFIG(metal)
+    graphicsApi = QRhi::Metal;
+#elif QT_CONFIG(vulkan)
+    graphicsApi = QRhi::Vulkan;
+#else
+    graphicsApi = QRhi::OpenGLES2;
+#endif
+
+    QCommandLineParser cmdLineParser;
+    cmdLineParser.addHelpOption();
+    QCommandLineOption nullOption({ "n", "null" }, QLatin1String("Null"));
+    cmdLineParser.addOption(nullOption);
+    QCommandLineOption glOption({ "g", "opengl" }, QLatin1String("OpenGL (2.x)"));
+    cmdLineParser.addOption(glOption);
+    QCommandLineOption vkOption({ "v", "vulkan" }, QLatin1String("Vulkan"));
+    cmdLineParser.addOption(vkOption);
+    QCommandLineOption d3d11Option({ "d", "d3d11" }, QLatin1String("Direct3D 11"));
+    cmdLineParser.addOption(d3d11Option);
+    QCommandLineOption d3d12Option({ "D", "d3d12" }, QLatin1String("Direct3D 12"));
+    cmdLineParser.addOption(d3d12Option);
+    QCommandLineOption mtlOption({ "m", "metal" }, QLatin1String("Metal"));
+    cmdLineParser.addOption(mtlOption);
+
+    cmdLineParser.process(app);
+    if (cmdLineParser.isSet(nullOption))
+        graphicsApi = QRhi::Null;
+    if (cmdLineParser.isSet(glOption))
+        graphicsApi = QRhi::OpenGLES2;
+    if (cmdLineParser.isSet(vkOption))
+        graphicsApi = QRhi::Vulkan;
+    if (cmdLineParser.isSet(d3d11Option))
+        graphicsApi = QRhi::D3D11;
+    if (cmdLineParser.isSet(d3d12Option))
+        graphicsApi = QRhi::D3D12;
+    if (cmdLineParser.isSet(mtlOption))
+        graphicsApi = QRhi::Metal;
+
+    qDebug("Selected graphics API is %s", qPrintable(graphicsApiName(graphicsApi)));
+    qDebug("This is a multi-api example, use command line arguments to override:\n%s", qPrintable(cmdLineParser.helpText()));
+
+    return graphicsApi;
+}