提高 Direct3D 中纹理样本的质量

Question

我正在使用 directx 11 渲染 video.I 创建一个 Texture2D 并将 rgba 视频数据复制到 it.Also 它是像素的资源 shader.Here 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和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);
}

我已经为设备上下文设置了示例状态：

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;
}

我的问题是这次window显示的视频尺寸小于video.At尺寸时如何提高渲染质量，shaderTexture.Sample 在像素着色器中是关键 point.But 我不知道如何获得更好的样本 result.I 我尝试更改样本状态的参数但没有 work.I'不熟悉 DirectX.So 我是不是漏掉了什么？ PS:I 有两张对比图。这是 d3d 方式： DirectX render 这是 gdi 方式和自己缩放图像： gdi render 我们可以看到，尤其是文本是模糊的。

Answer 1

您可能需要研究的一件事是为相关纹理生成一个 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择）将利用纹理的 mip 级别纹理。

mip 计数应与 1 + log2(max(width, height)) 一致，但根据最小显示尺寸，您可以使用更少的 mip。然后设置 textureDesc.MiscFlags 以包含 D3D11_RESOURCE_MISC_GENERATE_MIPS 标志，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），你就可以在即时上下文中调用 ID3D11DeviceContext::GenerateMips()。

请注意，绑定和生成 mip 标志不适用于动态资源，因此您需要保持原始动态纹理不变，并添加标记为 [=18 的第二个纹理=] 与 >1 mip 级别和上面指定的其他标志。然后，一旦您完成了暂存（动态）纹理的填充，调用 ID3D11DeviceContext::CopyResource 复制到新纹理。你也会让你的着色器资源视图指向这个新人。

这可能会有一点帮助，但它仍然不如真正高质量的缩小滤波器好。

提高 Direct3D 中纹理样本的质量

Improve the quality of texture sample in Direct3D

textures

direct3d

render

scale