Question

我正在使用directx 11渲染视频。我创建了一个Texture2D并将rgba视频数据复制到其中。它也是像素着色器的资源。这是代码：

void CreateTexture(int nWidth, int nHeight)
{
    D3D11_TEXTURE2D_DESC textureDesc;
    textureDesc.Width = nWidth;//Video width
    textureDesc.Height = nHeight;//Video height
    textureDesc.MipLevels = 1;
    textureDesc.ArraySize = 1;
    textureDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    textureDesc.SampleDesc.Count = 1;
    textureDesc.Usage = D3D11_USAGE_DYNAMIC;
    textureDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
    textureDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
    textureDesc.MiscFlags = 0;
    m_pD3dDevice->CreateTexture2D(&textureDesc, NULL, &m_pRGBATexture);

    D3D11_SHADER_RESOURCE_VIEW_DESC shaderResourceViewDesc;
    ZeroMemory(&shaderResourceViewDesc, 
               sizeof(D3D11_SHADER_RESOURCE_VIEW_DESC));
    shaderResourceViewDesc.Format = textureDesc.Format;
    shaderResourceViewDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
    shaderResourceViewDesc.Texture2D.MostDetailedMip = 0;
    shaderResourceViewDesc.Texture2D.MipLevels = 1;
    m_pD3dDevice->CreateShaderResourceView(m_pRGBATexture, &shaderResourceViewDesc, &m_pRGBAShaderResouceView);

    ID3D11ShaderResourceView* pArrResources[] = {m_pRGBAShaderResouceView};
    m_pD3dDeviceContext->PSSetShaderResources(0, 1, &pArrShaderResourceView[0]);
}

void WriteVideoData(BYTE *pData, DWORD nSize)
{
    D3D11_MAPPED_SUBRESOURCE textureResource;
    ZeroMemory(&textureResource, sizeof(D3D11_MAPPED_SUBRESOURCE));
    hr = m_pD3dDeviceContext->Map(m_pRGBATexture, 0, D3D11_MAP_WRITE_DISCARD, 0, &textureResource);
    FAIL_RETURN_FALSE("Fail to map rgba texture resource.");
    BYTE *pMappedData = reinterpret_cast<BYTE*>(textureResource.pData);
    BYTE *pTmpBuffer = pFrameBuffer;
    for (int i = 0; i < nHeight; ++i)
    {
        CopyMemory(pMappedData, pTmpBuffer, nWidth * 4);
        pMappedData += rgbaTextureResource.RowPitch;
        pTmpBuffer += nWidth * 4;
    }
    m_pD3dDeviceContext->Unmap(m_pRGBATexture, 0);
}

以下是我创建交换链并设置渲染目标的方法：

void InitSwapChain(int nWidth, int nHeight)//Displayed window size
{
    DXGI_SWAP_CHAIN_DESC swapChainDesc;
    ZeroMemory(&swapChainDesc, sizeof(DXGI_SWAP_CHAIN_DESC));
    swapChainDesc.BufferDesc.Width = nWidth;
    swapChainDesc.BufferDesc.Height = nHeight;
    swapChainDesc.BufferDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;

    swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    swapChainDesc.BufferCount = 1;
    swapChainDesc.BufferDesc.Scaling = DXGI_MODE_SCALING_STRETCHED;
    swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
    swapChainDesc.SampleDesc.Count = 1;
    swapChainDesc.OutputWindow = m_hWnd;
    swapChainDesc.Windowed = true;

    IDXGIDevice * dxgiDevice = NULL;
    hr = m_pD3dDevice->QueryInterface(__uuidof(IDXGIDevice), (void **)&dxgiDevice);
    FAIL_RETURN_FALSE("Fail to Query IDXGIDevice");

    IDXGIAdapter * dxgiAdapter = NULL;
    hr = dxgiDevice->GetParent(__uuidof(IDXGIAdapter), (void **)&dxgiAdapter);
    SAFE_RELEASE(dxgiDevice);
    FAIL_RETURN_FALSE("Fail to Query IDXGIAdapter");

    IDXGIFactory * dxgiFactory = NULL;
    hr = dxgiAdapter->GetParent(__uuidof(IDXGIFactory), (void **)&dxgiFactory);
    SAFE_RELEASE(dxgiAdapter);
    FAIL_RETURN_FALSE("Fail to Query IDXGIFactory");

    hr = dxgiFactory->CreateSwapChain(m_pD3dDevice, &swapChainDesc, &m_pSwapChain);
    FAIL_RETURN_FALSE("Fail to create swap chain");
    ID3D11Texture2D *pBackBuffer = NULL;
    m_pSwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);
    hr = m_pD3dDevice->CreateRenderTargetView(pBackBuffer, NULL, &m_pBackBufferTargetView);
    m_pD3dDeviceContext->OMSetRenderTargets(1, &m_pBackBufferTargetView, m_pDepthStencilView);
}

我为设备上下文设置了样本状态：

void SetSampleState()
{
    D3D11_SAMPLER_DESC samplerDesc;
    ZeroMemory(&samplerDesc, sizeof(D3D11_SAMPLER_DESC));

    samplerDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;
    samplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;
    samplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;
    samplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;
    samplerDesc.MipLODBias = 0.0f;
    samplerDesc.MaxAnisotropy = 16;
    samplerDesc.ComparisonFunc = D3D11_COMPARISON_ALWAYS;
    samplerDesc.BorderColor[0] = 0;
    samplerDesc.BorderColor[1] = 0;
    samplerDesc.BorderColor[2] = 0;
    samplerDesc.BorderColor[3] = 0;
    samplerDesc.MinLOD = 0;
    samplerDesc.MaxLOD = D3D11_FLOAT32_MAX;

    HRESULT hr = m_pD3dDevice->CreateSamplerState(&samplerDesc, &m_pSamplerState);
    FAIL_RETURN_FALSE("Fail to create sampler state");

    m_pD3dDeviceContext->PSSetSamplers(0, 1, &m_pSamplerState);
}

我的像素着色器非常简单：

Texture2D shaderTexture;
SamplerState SampleType;

struct PixelInputType
{
    float4 position : SV_POSITION;
    float4 blendingColor : COLOR;
    float2 tex : TEXCOORD0;
};

struct PiXelOutput
{
    float4 color : SV_TARGET;
};

PiXelOutput main(PixelInputType input)
{
    PiXelOutput output;
    float4 color = shaderTexture.Sample(SampleType, input.tex);
    output.color.x = color.z;
    output.color.y = color.y;
    output.color.z = color.x;
    output.color.w = 1.0;
    return output;
}

我的问题是当显示视频的窗口大小小于视频大小时如何提高渲染质量。此时，像素着色器中的 shaderTexture.Sample 是关键点。但是我不知道如何获得更好的样本结果。我已经尝试更改样本状态的参数而且它不起作用。我对DirectX不熟悉。所以我错过了什么？ PS：我有两张图片用于对比。这个是d3d方式： DirectX render 这个是gdi方式和缩放图像自己： gdi render 我们可以看到特别是文本是模糊的。

Answer 1

您可能想要研究的一件事是为所讨论的纹理生成一个mip链，因为您的D3D11_FILTER_MIN_MAG_MIP_LINEAR过滤状态（这是您使用的最佳选项）将利用纹理的mip级别。

mip计数应该与1 + log2(max(width, height))一致，但根据最小显示尺寸，您可以使用更少的mips。然后设置textureDesc.MiscFlags以包含D3D11_RESOURCE_MISC_GENERATE_MIPS标记，并确保BindFlags成员包含D3D11_BIND_SHADER_RESOURCE和D3D11_BIND_RENDER_TARGET。然后，一旦你填充了纹理内容（在Unmap之后），你可以在直接上下文中调用ID3D11DeviceContext::GenerateMips()。

请注意，绑定和生成mip标志不会对动态资源起作用，因此您需要按原样保留原始动态纹理，并添加第二个纹理。 s标记为D3D11_USAGE_DEFAULT，其中＆gt; 1 mip级别和上面指定的其他标志。然后，一旦您完成了分段（动态）纹理的填充，请调用ID3D11DeviceContext::CopyResource以复制到新纹理。您还要将着色器资源视图指向这个新人。

这可能会有所帮助，但它仍然不如真正高质量的低档过滤器好。

提高Direct3D中纹理样本的质量

1 个答案: