c++ - CheckMultisampleQualityLevels(...) 表示该卡不支持 MSAA(例如我的 GeForce GTX 780 不支持)？

Question

我使用 CheckMultisampleQualityLevels(...) 在我的硬件上建立 MSAA 支持。我按照这个顺序做:

1. D3D11CreateDevice(...) 给我 device
2. device->CheckMultisampleQualityLevels(...)
3. 将结果传递给 DXGI_SWAP_CHAIN_DESC.SampleDesc
4. CreateSwapChain(...) 给定 DXGI_SWAP_CHAIN_DESC

问题是，对于 pNumQualityLevels，CheckMultisampleQualityLevels(...) 总是给我 0。而且我确定我的显卡支持某些 MSAA(我已经在 GeForce gtx 780 和其他显卡上测试了该程序，结果相同)。

我错过了什么吗？我应该在 CheckMultisampleQualityLevels(...) 之前调用其他东西吗？

代码:

创 build 备:

UINT createDeviceFlags = 0;
#ifdef DEBUG_DIRECTX
 createDeviceFlags |= D3D11_CREATE_DEVICE_DEBUG;
#endif

D3D_DRIVER_TYPE driverTypes[] = {
    D3D_DRIVER_TYPE_HARDWARE,
    D3D_DRIVER_TYPE_WARP,
    D3D_DRIVER_TYPE_REFERENCE,
};
std::string driverTypesNames[] = {
    "D3D_DRIVER_TYPE_HARDWARE",
    "D3D_DRIVER_TYPE_WARP",
    "D3D_DRIVER_TYPE_REFERENCE",
};
UINT numDriverTypes = ARRAYSIZE(driverTypes);

D3D_FEATURE_LEVEL featureLevels[] = {
    D3D_FEATURE_LEVEL_11_0,
    D3D_FEATURE_LEVEL_10_1,
    D3D_FEATURE_LEVEL_10_0,
};
std::string featureLevelsNames[] = {
    "D3D_FEATURE_LEVEL_11_0",
    "D3D_FEATURE_LEVEL_10_1",
    "D3D_FEATURE_LEVEL_10_0",
};
UINT numFeatureLevels = ARRAYSIZE(featureLevels);

D3D_FEATURE_LEVEL g_featureLevel = D3D_FEATURE_LEVEL_11_0;
for(UINT driverTypeIndex = 0; driverTypeIndex < numDriverTypes; driverTypeIndex++){
    driverType = driverTypes[driverTypeIndex];
    result = D3D11CreateDevice(NULL, driverType, NULL, createDeviceFlags, featureLevels, numFeatureLevels, D3D11_SDK_VERSION, &device, &g_featureLevel, &context);
    if(SUCCEEDED(result)){
        LOG(logDEBUG1, "Driver type: " << driverTypesNames[driverTypeIndex] << ".", MOD_GRAPHIC);
        break;
    }
}
ERROR_HANDLE(SUCCEEDED(result), L"Could not create device (DirectX 11).", MOD_GRAPHIC);

检查多样本质量水平(基于 vertexwahn.de article ):

sampleCountOut = 1;
maxQualityLevelOut = 0;
for(UINT sampleCount = 1; sampleCount <= D3D11_MAX_MULTISAMPLE_SAMPLE_COUNT; sampleCount++){
    UINT maxQualityLevel = 0;
    HRESULT hr = device->CheckMultisampleQualityLevels(DXGI_FORMAT_R8G8B8A8_UNORM, sampleCount, &maxQualityLevel);
    if(maxQualityLevel > 0){
        maxQualityLevel--;
    }
    ERROR_HANDLE(hr == S_OK, L"CheckMultisampleQualityLevels failed.", MOD_GRAPHIC);

    if(maxQualityLevel > 0){
        LOG(logDEBUG1, "MSAA " << sampleCount << "X supported with " << maxQualityLevel << " quality levels.", MOD_GRAPHIC);
        sampleCountOut = sampleCount;
        maxQualityLevelOut = maxQualityLevel;
    }
}

交换链:

DXGI_SWAP_CHAIN_DESC sd;
ZeroMemory(&sd, sizeof(sd));
sd.BufferCount = 1;
sd.BufferDesc.Width = width;
sd.BufferDesc.Height = height;
sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
sd.BufferDesc.RefreshRate.Numerator = 60;
sd.BufferDesc.RefreshRate.Denominator = 1;
sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
sd.OutputWindow = *hwnd;
sd.SampleDesc.Count = sampleCount;
sd.SampleDesc.Quality = maxQualityLevel;
sd.Windowed = false;
sd.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;     // allow full-screen switchin


//based on http://stackoverflow.com/questions/27270504/directx-creating-the-swapchain
IDXGIDevice * dxgiDevice = 0;
HRESULT hr = device->QueryInterface(__uuidof(IDXGIDevice), (void **)& dxgiDevice);
ERROR_HANDLE(SUCCEEDED(hr), L"Query for IDXGIDevice failed.", MOD_GRAPHIC);

IDXGIAdapter * dxgiAdapter = 0;
hr = dxgiDevice->GetParent(__uuidof(IDXGIAdapter), (void **)& dxgiAdapter);
ERROR_HANDLE(SUCCEEDED(hr), L"Could not get IDXGIAdapter.", MOD_GRAPHIC);

IDXGIFactory * dxgiFactory = 0;
hr = dxgiAdapter->GetParent(__uuidof(IDXGIFactory), (void **)& dxgiFactory);
ERROR_HANDLE(SUCCEEDED(hr), L"Could not get IDXGIFactory.", MOD_GRAPHIC);

// This system only has DirectX 11.0 installed (let's assume it)
result = dxgiFactory->CreateSwapChain(device, &sd, &swapChain);
LOG(logDEBUG1, "This system only has DirectX 11.0 installed. CreateSwapChain(...) used.", MOD_GRAPHIC);

ERROR_HANDLE(result == S_OK, L"Could not swap chain.", MOD_GRAPHIC);

我的 ERROR_HANDLE(...) 宏永远不会触发(第一个参数在所有情况下都为真)。日志显示我使用 D3D_DRIVER_TYPE_HARDWARE 作为驱动程序类型。

DirectX 调试器说(这是一些问题，但我不认为这是 CheckMultisampleQualityLevels(...) 给我错误结果的原因):

DXGI WARNING: IDXGISwapChain::Present: Fullscreen presentation inefficiencies incurred due to application not using IDXGISwapChain::ResizeBuffers appropriately, specifying a DXGI_MODE_DESC not available in IDXGIOutput::GetDisplayModeList, or not using DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH.DXGI_SWAP_CHAIN_DESC::BufferDesc = { 1600, 900, { 60, 1 }, R8G8B8A8_UNORM, 0, 0 }; DXGI_SWAP_CHAIN_DESC::SampleDesc = { 8, 0 }; DXGI_SWAP_CHAIN_DESC::Flags = 0x2; [ MISCELLANEOUS WARNING #98: ]

Answer 1

您的代码先从 maxQualityLevels 中减去 1，然后再检查它是否大于零。初始值为 1 表示以质量级别 0 创建目标是有效的。

假设您希望它适用于所有供应商，您只需要真正检查它是否 > 0，然后创建质量 = 0 的表面即可。

质量级别 > 0 是特定于供应商的，对于不同的 GPU 可能意味着任意数量的东西。 Nvidia 的 CSAA 和 AMD 的 EQAA 都可以通过非零质量级别获得，但您需要查看他们自己的文档才能弄清楚每个质量级别的实际含义。它们在功能上也与传统 MSAA 略有不同。 “质量”有点误导，因为数字越大并不一定意味着质量越高，称其为“模式”更合适

同时查看:

http://www.nvidia.com/object/coverage-sampled-aa.html

和

http://developer.amd.com/wordpress/media/2012/10/EQAA%2520Modes%2520for%2520AMD%2520HD%25206900%2520Series%2520Cards.pdf