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++ // Copyright (C) 2020 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include "engine.h"
++ #include <QLibrary>
++ #include <comdef.h>
++
++ #define ENABLE_DEBUG_LAYER
++
++ Engine::~Engine()
++ {
++ RELEASE(m_context);
++ RELEASE(m_device);
++ RELEASE(m_dxgiFactory);
++ }
++
++ QString comErrorMessage(HRESULT hr)
++ {
++ const _com_error comError(hr);
++ QString result = QLatin1String("Error 0x") + QString::number(ulong(hr), 16);
++ if (const wchar_t *msg = comError.ErrorMessage())
++ result += QLatin1String(": ") + QString::fromWCharArray(msg);
++ return result;
++ }
++
++ bool Engine::create()
++ {
++ using PtrCreateDXGIFactory2 = HRESULT (WINAPI *)(UINT, REFIID, void **);
++ QLibrary dxgilib(QStringLiteral("dxgi"));
++ if (auto createDXGIFactory2 = reinterpret_cast<PtrCreateDXGIFactory2>(dxgilib.resolve("CreateDXGIFactory2"))) {
++ const HRESULT hr = createDXGIFactory2(0, IID_IDXGIFactory2, reinterpret_cast<void **>(&m_dxgiFactory));
++ if (FAILED(hr)) {
++ qWarning("CreateDXGIFactory2() failed to create DXGI factory: %s", qPrintable(comErrorMessage(hr)));
++ return false;
++ }
++ } else {
++ qWarning("Unable to resolve CreateDXGIFactory2()");
++ return false;
++ }
++
++ uint flags = 0;
++ #ifdef ENABLE_DEBUG_LAYER
++ flags |= D3D11_CREATE_DEVICE_DEBUG;
++ #endif
++ // use the default hardware adapter
++ HRESULT hr = D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, flags,
++ nullptr, 0, D3D11_SDK_VERSION,
++ &m_device, &m_featureLevel, &m_context);
++ if (FAILED(hr)) {
++ qWarning("Failed to create D3D11 device and context: %s", qPrintable(comErrorMessage(hr)));
++ return false;
++ }
++
++ return true;
++ }
++
++ QSize Engine::swapchainSizeForWindow(QWindow *window) const
++ {
++ const QSize size = window->size() * window->devicePixelRatio();
++ return QSize(qMax(8, size.width()), qMax(8, size.height()));
++ }
++
++ Swapchain Engine::createSwapchain(QWindow *window)
++ {
++ Swapchain sc = {};
++ const HWND hwnd = reinterpret_cast<HWND>(window->winId());
++ const QSize pixelSize = swapchainSizeForWindow(window);
++
++ // only care about flip discard swapchains here; the old stuff (discard) is
++ // not supported in this example
++
++ DXGI_SWAP_CHAIN_DESC1 desc = {};
++ desc.Width = UINT(pixelSize.width());
++ desc.Height = UINT(pixelSize.height());
++ desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
++ desc.SampleDesc.Count = 1;
++ desc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
++ desc.BufferCount = 2;
++ desc.Scaling = DXGI_SCALING_STRETCH;
++ desc.SwapEffect = DXGI_SWAP_EFFECT(4); // DXGI_SWAP_EFFECT_FLIP_DISCARD
++
++ IDXGISwapChain1 *swapchain = nullptr;
++ HRESULT hr = static_cast<IDXGIFactory2 *>(m_dxgiFactory)->CreateSwapChainForHwnd(m_device, hwnd, &desc,
++ nullptr, nullptr, &swapchain);
++ if (FAILED(hr)) {
++ qWarning("Failed to create D3D11 swapchain: %s", qPrintable(comErrorMessage(hr)));
++ return sc;
++ }
++
++ sc.swapchain = swapchain;
++ sc.pixelSize = pixelSize;
++ createSwapchainBuffers(&sc);
++ return sc;
++ }
++
++ void Engine::createSwapchainBuffers(Swapchain *sc)
++ {
++ ID3D11Texture2D *tex = nullptr;
++ HRESULT hr = sc->swapchain->GetBuffer(0, IID_ID3D11Texture2D, reinterpret_cast<void **>(&tex));
++ if (FAILED(hr)) {
++ qWarning("Failed to query swapchain backbuffer: %s", qPrintable(comErrorMessage(hr)));
++ return;
++ }
++
++ ID3D11RenderTargetView *rtv = nullptr;
++ D3D11_RENDER_TARGET_VIEW_DESC rtvDesc = {};
++ rtvDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
++ rtvDesc.ViewDimension = D3D11_RTV_DIMENSION_TEXTURE2D;
++ hr = m_device->CreateRenderTargetView(tex, &rtvDesc, &rtv);
++ if (FAILED(hr)) {
++ qWarning("Failed to create rtv for swapchain backbuffer: %s", qPrintable(comErrorMessage(hr)));
++ tex->Release();
++ return;
++ }
++
++ D3D11_TEXTURE2D_DESC texDesc = {};
++ texDesc.Width = UINT(sc->pixelSize.width());
++ texDesc.Height = UINT(sc->pixelSize.height());
++ texDesc.MipLevels = 1;
++ texDesc.ArraySize = 1;
++ texDesc.SampleDesc.Count = 1;
++ texDesc.Usage = D3D11_USAGE_DEFAULT;
++ texDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
++ texDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
++
++ ID3D11Texture2D *ds = nullptr;
++ hr = m_device->CreateTexture2D(&texDesc, nullptr, &ds);
++ if (FAILED(hr)) {
++ qWarning("Failed to create depth-stencil buffer: %s", qPrintable(comErrorMessage(hr)));
++ tex->Release();
++ rtv->Release();
++ return;
++ }
++
++ ID3D11DepthStencilView *dsv = nullptr;
++ D3D11_DEPTH_STENCIL_VIEW_DESC dsvDesc = {};
++ dsvDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
++ dsvDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
++ hr = m_device->CreateDepthStencilView(ds, &dsvDesc, &dsv);
++ if (FAILED(hr)) {
++ qWarning("Failed to create dsv: %s", qPrintable(comErrorMessage(hr)));
++ tex->Release();
++ rtv->Release();
++ ds->Release();
++ return;
++ }
++
++ sc->tex = tex;
++ sc->rtv = rtv;
++ sc->ds = ds;
++ sc->dsv = dsv;
++ }
++
++ void Engine::resizeSwapchain(Swapchain *sc, QWindow *window)
++ {
++ const QSize pixelSize = swapchainSizeForWindow(window);
++
++ RELEASE(sc->dsv);
++ RELEASE(sc->ds);
++ RELEASE(sc->rtv);
++ RELEASE(sc->tex);
++
++ HRESULT hr = sc->swapchain->ResizeBuffers(2, UINT(pixelSize.width()), UINT(pixelSize.height()),
++ DXGI_FORMAT_R8G8B8A8_UNORM, 0);
++ if (FAILED(hr)) {
++ qWarning("Failed to resize D3D11 swapchain: %s", qPrintable(comErrorMessage(hr)));
++ return;
++ }
++
++ sc->pixelSize = pixelSize;
++ createSwapchainBuffers(sc);
++ }
++
++ void Swapchain::destroy()
++ {
++ RELEASE(dsv);
++ RELEASE(ds);
++ RELEASE(rtv);
++ RELEASE(tex);
++ RELEASE(swapchain);
++ pixelSize = QSize();
++ }