DirectX12 helloworld

以下是使用 DirectX 12 编写的 "Hello World" 示例代码：

#include <windows.h>
#include <d3d12.h>
#include <dxgi1_4.h>

#pragma comment(lib, "d3d12.lib")
#pragma comment(lib, "dxgi.lib")

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // 创建窗口
    HWND hWnd = CreateWindowEx(0, L"static", L"DirectX12 HelloWorld", WS_OVERLAPPEDWINDOW, 0, 0, 640, 480, nullptr, nullptr, hInstance, nullptr);

    // 初始化 DirectX 12
    IDXGIFactory4* dxgiFactory = nullptr;
    HRESULT hr = CreateDXGIFactory1(IID_PPV_ARGS(&dxgiFactory));
    if (FAILED(hr)) return 1;

    IDXGIAdapter1* adapter = nullptr;
    for (UINT adapterIndex = 0; DXGI_ERROR_NOT_FOUND != dxgiFactory->EnumAdapters1(adapterIndex, &adapter); ++adapterIndex)
    {
        DXGI_ADAPTER_DESC1 adapterDesc;
        adapter->GetDesc1(&adapterDesc);

        if (adapterDesc.Flags & DXGI_ADAPTER_FLAG_SOFTWARE)
        {
            continue;
        }

        // 创建设备
        hr = D3D12CreateDevice(adapter, D3D_FEATURE_LEVEL_11_0, IID_PPV_ARGS(&device));
        if (FAILED(hr)) return 1;

        // 退出循环
        break;
    }

    // 创建命令队列
    D3D12_COMMAND_QUEUE_DESC queueDesc = {};
    queueDesc.Type = D3D12_COMMAND_LIST_TYPE_DIRECT;
    hr = device->CreateCommandQueue(&queueDesc, IID_PPV_ARGS(&commandQueue));
    if (FAILED(hr)) return 1;

    // 创建交换链
    DXGI_MODE_DESC backBufferDesc = {};
    backBufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    backBufferDesc.Width = 640;
    backBufferDesc.Height = 480;
    backBufferDesc.RefreshRate.Numerator = 60;
    backBufferDesc.RefreshRate.Denominator = 1;
    backBufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;
    backBufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;

    DXGI_SWAP_CHAIN_DESC swapChainDesc = {};
    swapChainDesc.BufferCount = 2;
    swapChainDesc.BufferDesc = backBufferDesc;
    swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    swapChainDesc.OutputWindow = hWnd;
    swapChainDesc.SampleDesc.Count = 1;
    swapChainDesc.Windowed = TRUE;

    IDXGISwapChain* swapChain = nullptr;
    hr = dxgiFactory->CreateSwapChain(commandQueue, &swapChainDesc, &swapChain);
    if (FAILED(hr)) return 1;

    // 创建渲染目标视图
    ID3D12Resource* backBuffer = nullptr;
    hr = swapChain->GetBuffer(0, IID_PPV_ARGS(&backBuffer));
    if (FAILED(hr)) return 1;

    D3D12_DESCRIPTOR_HEAP_DESC heapDesc = {};
    heapDesc.NumDescriptors = 1;
    heapDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_RTV;
    heapDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;

    ID3D12DescriptorHeap* rtvHeap = nullptr;
    hr = device->CreateDescriptorHeap(&heapDesc, IID_PPV_ARGS(&rtvHeap));
    if (FAILED(hr)) return 1;

    CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(rtvHeap->GetCPUDescriptorHandleForHeapStart());
    device->CreateRenderTargetView(backBuffer, nullptr, rtvHandle);

    // 渲染循环
    MSG msg = {};
    while (msg.message != WM_QUIT)
    {
        if (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        else
        {
            // 清除后台缓冲区
            float clearColor[] = { 0.0f, 0.2f, 0.4f, 1.0f };
            commandList->ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);

            // 切换后台缓冲区
            hr = swapChain->Present(1, 0);
            if (FAILED(hr)) return 1;
        }
    }

    return 0;
}

这段代码创建了一个包含一个后台缓冲区的窗口，并在该缓冲区内清除颜色并显示它。