如何使用nvdia硬解视频帧后直接显存零拷贝d3d上屏，请给出实例代码

要实现使用 NVIDIA 硬解视频帧后直接显存零拷贝 D3D 上屏，可以使用 NVIDIA 的 CUDA 解码库和 D3D 引擎。以下是一个简单的示例代码，以帮助您更好地了解如何实现此操作。

首先，需要使用 CUDA 解码库解码视频帧，并将解码后的帧存储在 CUDA 设备内存中。然后，需要将帧从 CUDA 设备内存传输到 D3D 纹理中。最后，可以使用 D3D 引擎将纹理渲染到屏幕上。

以下是示例代码：

#include <cuda.h>
#include <nvcuvid.h>
#include <d3d11.h>

// 初始化 CUDA 和 D3D 环境

CUcontext cuContext = NULL;
CUdevice cuDevice = NULL;

ID3D11Device* d3dDevice = NULL;
ID3D11DeviceContext* d3dContext = NULL;
IDXGISwapChain* swapChain = NULL;
ID3D11RenderTargetView* renderTargetView = NULL;

HRESULT InitCUDAAndD3D()
{
    // 初始化 CUDA 上下文
    cuInit(0);
    cuDeviceGet(&cuDevice, 0);
    cuCtxCreate(&cuContext, 0, cuDevice);

    // 初始化 D3D 设备和交换链
    D3D_FEATURE_LEVEL featureLevel;
    HRESULT hr = D3D11CreateDeviceAndSwapChain(
        NULL, D3D_DRIVER_TYPE_HARDWARE, NULL, 0, NULL, 0,
        D3D11_SDK_VERSION, &swapChainDesc, &swapChain, &d3dDevice,
        &featureLevel, &d3dContext);

    // 创建渲染目标视图
    ID3D11Texture2D* backBuffer;
    swapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&backBuffer);
    d3dDevice->CreateRenderTargetView(backBuffer, NULL, &renderTargetView);
    backBuffer->Release();

    // 设置视口
    D3D11_VIEWPORT viewport = { 0, 0, (FLOAT)width, (FLOAT)height, 0.0f, 1.0f };
    d3dContext->RSSetViewports(1, &viewport);

    return hr;
}

// 解码视频帧并将帧传输到 D3D 纹理

CUvideodecoder cuDecoder = NULL;
CUvideoctxlock cuCtxLock = NULL;
CUdeviceptr dptrFrame = 0;

ID3D11Texture2D* d3dTexture = NULL;
ID3D11Texture2D* stagingTexture = NULL;
ID3D11Device* pDevice = NULL;

void HandleVideoFrame(CUVIDPARSERDISPINFO* pDispInfo)
{
    // 锁定 CUDA 上下文
    cuvidCtxLockCreate(&cuCtxLock, cuContext, 0);

    // 解码器处理器
    CUVIDPROCPARAMS params = { 0 };
    params.progressive_frame = pDispInfo->progressive_frame;
    params.second_field = 0;
    params.top_field_first = pDispInfo->top_field_first;
    params.unpaired_field = 0;
    params.output_stream = NULL;
    params.current_frame = pDispInfo->picture_index;

    // 解码视频帧
    cuvidDecodePicture(cuDecoder, pDispInfo->picture_index, &params);

    // 获取解码后的帧
    CUVIDGETDECODESTATUS status = { 0 };
    status.progressive_frame = pDispInfo->progressive_frame;
    cuvidGetDecodeStatus(cuDecoder, pDispInfo->picture_index, &status);
    if (status.decodeStatus == NVDEC_SUCCESS)
    {
        // 锁定 CUDA 上下文
        cuCtxLock(cuCtxLock, 0);

        // 获取 CUDA 设备指针
        cuvidMapVideoFrame(cuDecoder, pDispInfo->picture_index, &dptrFrame, &pitch, &cuvidCtxLock, 0);

        // 创建 D3D 纹理
        D3D11_TEXTURE2D_DESC desc;
        ZeroMemory(&desc, sizeof(desc));
        desc.Width = width;
        desc.Height = height;
        desc.MipLevels = 1;
        desc.ArraySize = 1;
        desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
        desc.SampleDesc.Count = 1;
        desc.Usage = D3D11_USAGE_DEFAULT;
        desc.BindFlags = D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_RENDER_TARGET;
        desc.CPUAccessFlags = 0;
        pDevice->CreateTexture2D(&desc, NULL, &d3dTexture);

        // 创建 D3D 纹理副本
        ZeroMemory(&desc, sizeof(desc));
        desc.Width = width;
        desc.Height = height;
        desc.MipLevels = 1;
        desc.ArraySize = 1;
        desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
        desc.SampleDesc.Count = 1;
        desc.Usage = D3D11_USAGE_STAGING;
        desc.BindFlags = 0;
        desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
        pDevice->CreateTexture2D(&desc, NULL, &stagingTexture);

        // 将 CUDA 设备指针复制到 D3D 纹理
        d3dContext->CopyResource(stagingTexture, d3dTexture);
        d3dContext->CopySubresourceRegion(d3dTexture, 0, 0, 0, 0, stagingTexture, 0, NULL);

        // 解锁 CUDA 上下文
        cuvidUnmapVideoFrame(cuDecoder, dptrFrame);
        cuCtxUnlock(cuCtxLock, 0);
    }

    // 解锁 CUDA 上下文
    cuvidCtxUnlock(cuCtxLock, 0);
}

// 渲染 D3D 纹理到屏幕上

void Render()
{
    // 清除渲染目标视图
    FLOAT clearColor[4] = { 0.0f, 0.0f, 0.0f, 0.0f };
    d3dContext->ClearRenderTargetView(renderTargetView, clearColor);

    // 设置渲染目标视图
    d3dContext->OMSetRenderTargets(1, &renderTargetView, NULL);

    // 绘制 D3D 纹理
    D3D11_VIEWPORT viewport = { 0, 0, (FLOAT)width, (FLOAT)height, 0.0f, 1.0f };
    d3dContext->RSSetViewports(1, &viewport);
    d3dContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLESTRIP);
    d3dContext->IASetInputLayout(NULL);
    d3dContext->VSSetShader(NULL, NULL, 0);
    d3dContext->PSSetShader(NULL, NULL, 0);
    d3dContext->PSSetShaderResources(0, 1, &d3dTexture);
    d3dContext->Draw(4, 0);

    // 切换缓冲区
    swapChain->Present(1, 0);
}

// 主函数

int main()
{
    // 初始化 CUDA 和 D3D 环境
    InitCUDAAndD3D();

    // 创建解码器
    CUVIDDECODECREATEINFO createInfo = { 0 };
    createInfo.ulWidth = width;
    createInfo.ulHeight = height;
    createInfo.ulNumDecodeSurfaces = 16;
    createInfo.CodecType = cudaVideoCodec_H264;
    createInfo.ulMaxNumDecodeSurfaces = 16;
    createInfo.ulCreationFlags = cudaVideoCreate_PreferCUVID;
    cuvidCreateDecoder(&cuDecoder, &createInfo);

    // 处理视频帧
    while (true)
    {
        // 获取视频帧并解码
        CUVIDPARSERDISPINFO dispInfo;
        cuvidParseVideoData(cuParser, pData, nDataSize, 0);
        cuvidParseVideoData(cuParser, NULL, 0, -1);
        while (cuvidDequeueVideoFrame(cuDecoder, &dispInfo) == NVDEC_SUCCESS)
        {
            HandleVideoFrame(&dispInfo);
        }

        // 渲染 D3D 纹理到屏幕上
        Render();
    }

    // 释放资源
    cuvidDestroyDecoder(cuDecoder);
    cuvidDestroyVideoParser(cuParser);
    cuCtxDestroy(cuContext);
    swapChain->Release();
    d3dContext->Release();
    d3dDevice->Release();
    renderTargetView->Release();
    d3dTexture->Release();
    stagingTexture->Release();
    return 0;
}

需要注意的是，上面的代码仅作为示例，实际实现可能会有所不同。具体的实现取决于您的应用程序需求和硬件环境。此外，您还需要了解 CUDA 和 D3D 编程的基础知识，以便更好地理解代码和进行调试。