feat: 修复RHI渲染循环问题

- 修复RootSignature参数数量与HelloEarth一致
- 修复StaticMeshComponent中device为nullptr的问题
- 修复CommandList::Reset类型转换问题
- 修复RTV创建使用nullptr而不是rtvDesc
- 添加SwapChain的GetCurrentRenderTarget方法
- 修复DepthStencil创建问题(暂时跳过)
- 渲染循环基本可运行

engine/src/RHI/D3D12/D3D12Device.cpp

@@ -437,6 +437,18 @@ void* D3D12SwapChain::GetBuffer(uint32_t index) {
     return GetBufferResource(index);
 }
 
+void* D3D12SwapChain::GetCurrentRenderTarget() {
+    uint32_t index = GetCurrentBufferIndex();
+    D3D12_CPU_DESCRIPTOR_HANDLE handle = m_rtvHeap->GetNativeHeap()->GetCPUDescriptorHandleForHeapStart();
+    UINT rtvSize = m_device->GetD3D12Device()->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV);
+    handle.ptr += index * rtvSize;
+    return (void*)handle.ptr;
+}
+
+void* D3D12SwapChain::GetDepthStencil() {
+    return nullptr;
+}
+
 void D3D12SwapChain::SetFullscreen(bool fullscreen) {
     m_fullscreen = fullscreen;
     m_swapChain->SetFullscreenState(fullscreen, nullptr);
@@ -660,7 +672,9 @@ D3D12CommandList::~D3D12CommandList() {
 }
 
 void D3D12CommandList::Reset(void* allocator) {
-    ID3D12CommandAllocator* d3dAllocator = static_cast<ID3D12CommandAllocator*>(allocator);
+    ICommandAllocator* cmdAlloc = static_cast<ICommandAllocator*>(allocator);
+    D3D12CommandAllocator* d3d12Alloc = static_cast<D3D12CommandAllocator*>(cmdAlloc);
+    ID3D12CommandAllocator* d3dAllocator = d3d12Alloc->GetNativeAllocator();
     m_commandList->Reset(d3dAllocator, nullptr);
 }