将 HLSL 像素着色器应用于 Win32 屏幕捕获

Question

一点背景知识：我正在尝试制作一个 Windows (10) 应用程序，使屏幕看起来像旧的 CRT 显示器、扫描线、模糊等等。我使用这个官方的 Microsoft screen capture demo 作为起点：在这个阶段我可以捕获一个 window，并在新的鼠标移动 window 中显示它，就好像它是原文window。

我正在尝试使用通常被认为是最好的 CRT 着色器的 CRT-Royale CRT shaders；这些以 .cg 格式提供。我使用 cgc 将它们转译为 hlsl，然后使用 fxc 将 hlsl 文件编译为已编译的着色器字节代码。我能够成功加载编译的着色器并创建像素着色器。然后我在 d3d 上下文中设置像素着色器。然后我尝试将捕获表面帧复制到像素着色器资源并设置创建的着色器资源。所有这些都构建并运行，但我没有看到输出图像有任何差异，我不确定如何继续。下面是相关代码。我不是 C++ 开发人员，而是将其作为个人项目，一旦我有了一个原始的工作版本，我计划将其开源。感谢任何建议，谢谢。

SimpleCapture::SimpleCapture(
IDirect3DDevice const& device,
GraphicsCaptureItem const& item)
{
m_item = item;
m_device = device;

// Set up 
auto d3dDevice = GetDXGIInterfaceFromObject<ID3D11Device>(m_device);
d3dDevice->GetImmediateContext(m_d3dContext.put());
auto size = m_item.Size();

m_swapChain = CreateDXGISwapChain(
    d3dDevice, 
    static_cast<uint32_t>(size.Width),
    static_cast<uint32_t>(size.Height),
    static_cast<DXGI_FORMAT>(DirectXPixelFormat::B8G8R8A8UIntNormalized),
    2);

// ADDED THIS
HRESULT hr1 = D3DReadFileToBlob(L"crt-royale-first-pass-ps_4_0.fxc", &ps_1_buffer);
HRESULT hr = d3dDevice->CreatePixelShader(
    ps_1_buffer->GetBufferPointer(),
    ps_1_buffer->GetBufferSize(),
    nullptr,
    &ps_1
);
m_d3dContext->PSSetShader(
    ps_1,
    nullptr,
    0
);
// END OF ADDED CHANGES

// Create framepool, define pixel format (DXGI_FORMAT_B8G8R8A8_UNORM), and frame size. 
m_framePool = Direct3D11CaptureFramePool::Create(
    m_device,
    DirectXPixelFormat::B8G8R8A8UIntNormalized,
    2,
    size);
m_session = m_framePool.CreateCaptureSession(m_item);
m_lastSize = size;
m_frameArrived = m_framePool.FrameArrived(auto_revoke, { this, &SimpleCapture::OnFrameArrived });
}

void SimpleCapture::OnFrameArrived(
Direct3D11CaptureFramePool const& sender,
winrt::Windows::Foundation::IInspectable const&)
{
auto newSize = false;

{
    auto frame = sender.TryGetNextFrame();
    auto frameContentSize = frame.ContentSize();

    if (frameContentSize.Width != m_lastSize.Width ||
        frameContentSize.Height != m_lastSize.Height)
    {
        // The thing we have been capturing has changed size.
        // We need to resize our swap chain first, then blit the pixels.
        // After we do that, retire the frame and then recreate our frame pool.
        newSize = true;
        m_lastSize = frameContentSize;
        m_swapChain->ResizeBuffers(
            2, 
            static_cast<uint32_t>(m_lastSize.Width),
            static_cast<uint32_t>(m_lastSize.Height),
            static_cast<DXGI_FORMAT>(DirectXPixelFormat::B8G8R8A8UIntNormalized), 
            0);
    }

    {
        auto frameSurface = GetDXGIInterfaceFromObject<ID3D11Texture2D>(frame.Surface());

        com_ptr<ID3D11Texture2D> backBuffer;
        check_hresult(m_swapChain->GetBuffer(0, guid_of<ID3D11Texture2D>(), backBuffer.put_void()));

        // ADDED THIS
        D3D11_TEXTURE2D_DESC txtDesc = {};
        txtDesc.MipLevels = txtDesc.ArraySize = 1;
        txtDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
        txtDesc.SampleDesc.Count = 1;
        txtDesc.Usage = D3D11_USAGE_IMMUTABLE;
        txtDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE;

        auto d3dDevice = GetDXGIInterfaceFromObject<ID3D11Device>(m_device);

        ID3D11Texture2D *tex;
        d3dDevice->CreateTexture2D(&txtDesc, NULL,
            &tex);
        frameSurface.copy_to(&tex);

        d3dDevice->CreateShaderResourceView(
            tex,
            nullptr,
            srv_1
        );

        auto texture = srv_1;
        m_d3dContext->PSSetShaderResources(0, 1, texture);
        // END OF ADDED CHANGES

        m_d3dContext->CopyResource(backBuffer.get(), frameSurface.get());
    }
}

DXGI_PRESENT_PARAMETERS presentParameters = { 0 };
m_swapChain->Present1(1, 0, &presentParameters);
... // Truncated

Answer 1

着色器定义事物的绘制方式。但是，您不绘制任何东西 - 您只是复制，这就是着色器不执行任何操作的原因。

你应该做的是删除 CopyResource 调用，而是在后台缓冲区上绘制一个全屏四边形（这需要你创建一个可以绑定的顶点缓冲区，然后将后台缓冲区设置为渲染目标，最后调用 Draw/DrawIndexed 实际渲染一些东西，然后调用着色器）。

另外 - 因为我不确定你是否已经这样做并且只是从显示的代码中删除它 - 像 CreatePixelShader 这样的函数不会 return HRESULTs 只是为了好玩 - 你应该检查什么实际上是 returned，因为 DirectX 会默默地 return 处理大多数错误并希望您处理它们，而不是让您的程序崩溃。

将 HLSL 像素着色器应用于 Win32 屏幕捕获

Applying HLSL Pixel Shaders to Win32 Screen Capture

c++

shader

directx

hlsl

direct3d