imgui/examples/directx12_example/imgui_impl_dx12.h

// ImGui Win32 + DirectX12 binding
// In this binding, ImTextureID is used to store a 'D3D12_GPU_DESCRIPTOR_HANDLE' texture identifier. Read the FAQ about ImTextureID in imgui.cpp.

// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
// https://github.com/ocornut/imgui

struct ID3D12Device;
struct ID3D12GraphicsCommandList;
struct D3D12_CPU_DESCRIPTOR_HANDLE;
struct D3D12_GPU_DESCRIPTOR_HANDLE;

// cmdList is the command list that the implementation will use to render the
// GUI.
//
// Before calling ImGui::Render(), caller must prepare cmdList by resetting it
// and setting the appropriate render target and descriptor heap that contains
// fontSrvCpuDescHandle/fontSrvGpuDescHandle.
//
// fontSrvCpuDescHandle and fontSrvGpuDescHandle are handles to a single SRV
// descriptor to use for the internal font texture.
IMGUI_API bool        ImGui_ImplDX12_Init(void* hwnd, int numFramesInFlight,
                                          ID3D12Device* device, ID3D12GraphicsCommandList* cmdList,
                                          D3D12_CPU_DESCRIPTOR_HANDLE fontSrvCpuDescHandle,
                                          D3D12_GPU_DESCRIPTOR_HANDLE fontSrvGpuDescHandle);
IMGUI_API void        ImGui_ImplDX12_Shutdown();
IMGUI_API void        ImGui_ImplDX12_NewFrame();

// Use if you want to reset your rendering device without losing ImGui state.
IMGUI_API void        ImGui_ImplDX12_InvalidateDeviceObjects();
IMGUI_API bool        ImGui_ImplDX12_CreateDeviceObjects();

// Handler for Win32 messages, update mouse/keyboard data.
// You may or not need this for your implementation, but it can serve as reference for handling inputs.
// Commented out to avoid dragging dependencies on <windows.h> types. You can copy the extern declaration in your code.
/*
IMGUI_API LRESULT   ImGui_ImplDX12_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
*/