class XD3DApplication; class XD3D12Device; class XD3D12Dynamic { public: static void GetBestSupportedMSAASetting(DXGI_FORMAT format, UINT MSAACount, UINT& OutMSAACount, UINT& OutMSAALevels) { for (int sampleCount = MSAACount; sampleCount > 0; sampleCount--) { D3D12_FEATURE_DATA_MULTISAMPLE_QUALITY_LEVELS msQualityLevels = {}; msQualityLevels.Format = BackBufferFormat; msQualityLevels.SampleCount = sampleCount; ID3D12Device* device = XD3DApplication::GD3DApplicationPtr->GetD3D12Device(); if(SUCCEEDED(device->CheckFeatureSupport(D3D12_FEATURE_MULTISAMPLE_QUALITY_LEVELS, &msQualityLevels, sizeof(msQualityLevels)))) { OutMSAALevels = msQualityLevels.NumQualityLevels; OutMSAACount = sampleCount; break; } } } }; XD3D12Dynamic.h(24, 53): [C2027] 使用了未定义类型“XD3DApplication”

这段代码中的问题是XD3DApplication类的定义未被包含。可能是因为XD3DApplication类定义在另一个头文件中，而该头文件未被正确地包含。可以尝试在XD3D12Dynamic.h文件中添加XD3DApplication类的头文件包含语句来解决这个问题。例如，如果XD3DApplication类定义在"XD3DApplication.h"文件中，则可以添加以下语句来包含该文件：

#include "XD3DApplication.h"