refactor: 将 tests/D3D12 的 RootSignature 替换为 D3D12RootSignature

- 添加全局变量 gRootSignature
- 使用 D3D12RootSignature::Initialize 替代原生 API
- 测试通过

tests/D3D12/main.cpp

@@ -21,6 +21,7 @@
 #include "XCEngine/RHI/D3D12/D3D12DescriptorHeap.h"
 #include "XCEngine/RHI/D3D12/D3D12Fence.h"
 #include "XCEngine/RHI/D3D12/D3D12SwapChain.h"
+#include "XCEngine/RHI/D3D12/D3D12RootSignature.h"
 #include "XCEngine/RHI/D3D12/D3D12Screenshot.h"
 #include "XCEngine/Debug/Logger.h"
 #include "XCEngine/Debug/ConsoleLogSink.h"
@@ -65,6 +66,7 @@ UINT gDSVDescriptorSize = 0;
 // 命令相关
 XCEngine::RHI::D3D12CommandAllocator gCommandAllocator;
 XCEngine::RHI::D3D12CommandList gCommandList;
+XCEngine::RHI::D3D12RootSignature gRootSignature;
 
 // 同步对象
 XCEngine::RHI::D3D12Fence gFence;
@@ -277,14 +279,9 @@ ID3D12RootSignature* InitRootSignature() {
 	rootSignatureDesc.pStaticSamplers = samplerDesc;
 	rootSignatureDesc.Flags = D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT;
 
-	ID3DBlob* signature;
+	gRootSignature.Initialize(gDevice.GetDevice(), rootSignatureDesc);
-	HRESULT hResult = D3D12SerializeRootSignature(&rootSignatureDesc, D3D_ROOT_SIGNATURE_VERSION_1, &signature, nullptr);
-	ID3D12RootSignature* d3d12RootSignature;
-	gDevice.GetDevice()->CreateRootSignature(
-		0, signature->GetBufferPointer(), signature->GetBufferSize(),
-		IID_PPV_ARGS(&d3d12RootSignature));
 
-	return d3d12RootSignature;
+	return gRootSignature.GetRootSignature();
 }
 
 //=================================================================================