main.cpp

// Dear ImGui: standalone example application for DirectX 12
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs

// Important: to compile on 32-bit systems, the DirectX12 backend requires code to be compiled with '#define ImTextureID ImU64'.
// This is because we need ImTextureID to carry a 64-bit value and by default ImTextureID is defined as void*.
// This define is set in the example .vcxproj file and need to be replicated in your app or by adding it to your imconfig.h file.


#include "imgui.h"
#include "imgui_impl_win32.h"
#include "imgui_impl_dx12.h"
#include <d3d12.h>
#include <dxgi1_4.h>
#include <tchar.h>
#include <omp.h>
#include <random>
#include <thread>
#include <future>
#include <iostream>
#include <atomic>
#include <chrono>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <utility>
#include <vector>

#include "src/camera.h"
#include "src/renderer.h"
#include "src/settingLoader.h"
#include "src/sphere.h"

#ifdef _DEBUG
#define DX12_ENABLE_DEBUG_LAYER
#endif

#ifdef DX12_ENABLE_DEBUG_LAYER
#include <dxgidebug.h>
#pragma comment(lib, "dxguid.lib")
#endif


#pragma comment(lib, "dxgi")
#pragma comment(lib,"d3d12.lib")


struct FrameContext
{
    ID3D12CommandAllocator* CommandAllocator;
    UINT64                  FenceValue;
};

// Data
static int const                    NUM_FRAMES_IN_FLIGHT = 3;
static FrameContext                 g_frameContext[NUM_FRAMES_IN_FLIGHT] = {};
static UINT                         g_frameIndex = 0;

static int const                    NUM_BACK_BUFFERS = 3;
static ID3D12Device* g_pd3dDevice = NULL;
static ID3D12DescriptorHeap* g_pd3dRtvDescHeap = NULL;
static ID3D12DescriptorHeap* g_pd3dSrvDescHeap = NULL;
static ID3D12CommandQueue* g_pd3dCommandQueue = NULL;
static ID3D12GraphicsCommandList* g_pd3dCommandList = NULL;
static ID3D12Fence* g_fence = NULL;
static HANDLE                       g_fenceEvent = NULL;
static UINT64                       g_fenceLastSignaledValue = 0;
static IDXGISwapChain3* g_pSwapChain = NULL;
static HANDLE                       g_hSwapChainWaitableObject = NULL;
static ID3D12Resource* g_mainRenderTargetResource[NUM_BACK_BUFFERS] = {};
static D3D12_CPU_DESCRIPTOR_HANDLE  g_mainRenderTargetDescriptor[NUM_BACK_BUFFERS] = {};

// for rendering
// Camera
camera* cam = nullptr;

// World
hittableList world;

// Renderer
renderer* g = nullptr;


// Forward declarations of helper functions
bool CreateDeviceD3D(HWND hWnd);
void CleanupDeviceD3D();
void CreateRenderTarget();
void CleanupRenderTarget();
void WaitForLastSubmittedFrame();
FrameContext* WaitForNextFrameResources();
LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);

// Main code
//int WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR lpCmdLine, INT nCmdShow)
int main()
{
    int parentWindowWidth = 1550;
    int parentWindowHeight = 850;

    // Create application window
    //ImGui_ImplWin32_EnableDpiAwareness();
    WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(NULL), NULL, NULL, NULL, NULL, _T("ImGui Example"), NULL };
    ::RegisterClassEx(&wc);
    HWND hwnd = ::CreateWindow(wc.lpszClassName, _T("Ray Tracing Demo"), WS_OVERLAPPEDWINDOW, 100, 100, parentWindowWidth, parentWindowHeight, NULL, NULL, wc.hInstance, NULL);



    //Initialize Direct3D
    if (!CreateDeviceD3D(hwnd))
    {
        CleanupDeviceD3D();
        ::UnregisterClass(wc.lpszClassName, wc.hInstance);
        return 1;
    }

    // Show the window
    ::ShowWindow(hwnd, SW_SHOWDEFAULT);
    ::UpdateWindow(hwnd);

    // Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO(); (void)io;
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;       // Enable Keyboard Controls
    //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;           // Enable Docking
    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;         // Enable Multi-Viewport / Platform Windows
    //io.ConfigViewportsNoAutoMerge = true;
    //io.ConfigViewportsNoTaskBarIcon = true;

    // Setup Dear ImGui style
    ImGui::StyleColorsDark();
    //ImGui::StyleColorsLight();

    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
    ImGuiStyle& style = ImGui::GetStyle();
    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
    {
        style.WindowRounding = 0.0f;
        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
    }

    // Setup Platform/Renderer backends
    ImGui_ImplWin32_Init(hwnd);
    ImGui_ImplDX12_Init(g_pd3dDevice, NUM_FRAMES_IN_FLIGHT,
        DXGI_FORMAT_R8G8B8A8_UNORM, g_pd3dSrvDescHeap,
        g_pd3dSrvDescHeap->GetCPUDescriptorHandleForHeapStart(),
        g_pd3dSrvDescHeap->GetGPUDescriptorHandleForHeapStart());

    // Our state
    bool show_demo_window = true;
    bool show_another_window = false;
    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

    // rendering
    // data
    int imageWidth;
    int imageHeight;
    double aspectRatio = 16.0 / 9.0;
    int antiAliasingConf = 100;
    string imageName = "out";
    int outputType = 1;

    imageHeight = 720;
    imageWidth = imageHeight * aspectRatio; // 1280

    g = new renderer(imageWidth, imageHeight, antiAliasingConf);
    cam = new camera(imageWidth, imageHeight);

    // Create world
    // left right, down up, out in
    world.add(make_shared<sphere>(point3d(0, 0, -1.5), 0.5)); // mid
    world.add(make_shared<sphere>(point3d(-1, 0, -1), 0.5)); // left
    world.add(make_shared<sphere>(point3d(1, 0, -1), 0.5)); // right

    // rendering with threadCount threads
    std::vector<std::future<bool>> threadPool(g->threadCount);
    for (int threadIndex = 0; threadIndex < g->threadCount; threadIndex++) {
        threadPool[threadIndex] = std::async(&renderer::renderByThread, g, threadIndex);
    }

    // Main loop
    bool done = false;
    while (!done)
    {
        // Poll and handle messages (inputs, window resize, etc.)
        // See the WndProc() function below for our to dispatch events to the Win32 backend.
        MSG msg;
        while (::PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE))
        {
            ::TranslateMessage(&msg);
            ::DispatchMessage(&msg);
            if (msg.message == WM_QUIT)
                done = true;
        }

        if (done)
            break;

        // Start the Dear ImGui frame
        ImGui_ImplDX12_NewFrame();
        ImGui_ImplWin32_NewFrame();
        ImGui::NewFrame();


        ImGui::DockSpaceOverViewport(ImGui::GetMainViewport());

        // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
        /*if (show_demo_window)
            ImGui::ShowDemoWindow(&show_demo_window);*/

            // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
        {
            static float f = 0.0f;
            static int counter = 0;
            bool open = true;
            ImGui::SetNextWindowSize(ImVec2(100, parentWindowHeight));
            ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it.

            ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
            ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
            ImGui::Checkbox("Another Window", &show_another_window);

            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
            ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color

            if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
                counter++;
            ImGui::SameLine();
            ImGui::Text("counter = %d", counter);

            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
            ImGui::End();
        }

        {
            ImGui::Begin("Canvas");
            //bool rendered = (g->imagePixelBuffer.size() * g->imagePixelBuffer[0].size() / 4 == g->imageHeight * g->imageWidth);
            bool is_hovered;
            bool is_active;
            bool is_clicked;
            auto temp = g->imageWidth * g->imageHeight;


            ImGui::Text("Image width: %d, Image height: %d", g->imageWidth, g->imageHeight);
            std::vector<string> returnS = { "Rendering", "Finished Rendering" };
            auto rederStatus = returnS[g->totalProgress == g->threadCount];
            rederStatus = "Render Status: " + rederStatus;
            ImGui::Text(rederStatus.c_str());

            //ImGui::Checkbox("Clicked: ", &is_clicked);
            //ImGui::Checkbox("Active: ", &is_active);

            ImVec2 canvas_p0 = ImGui::GetCursorScreenPos();      // ImDrawList API uses screen coordinates!
            ImVec2 canvas_sz = ImGui::GetContentRegionAvail();   // Resize canvas to what's available
            // if smaller than 50, stay at 50
            //if (canvas_sz.x < 50.0f) canvas_sz.x = 50.0f;
            //if (canvas_sz.y < 50.0f) canvas_sz.y = 50.0f;

            canvas_sz = ImVec2(g->imageWidth, g->imageHeight);
            ImVec2 canvas_p1 = ImVec2(canvas_p0.x + canvas_sz.x, canvas_p0.y + canvas_sz.y);

            is_clicked = ImGui::InvisibleButton("canvas", canvas_sz, ImGuiButtonFlags_MouseButtonLeft | ImGuiButtonFlags_MouseButtonRight);
            is_hovered = ImGui::IsItemHovered(); // Hovered
            is_active = ImGui::IsItemActive();   // Held

            // Draw border and background color
            ImGuiIO& io = ImGui::GetIO();
            ImDrawList* draw_list = ImGui::GetWindowDrawList();
            draw_list->AddRectFilled(canvas_p0, canvas_p1, IM_COL32(50, 50, 50, 255));
            draw_list->AddRect(canvas_p0, canvas_p1, IM_COL32(255, 255, 255, 255));

            if (is_clicked) {

            }


            for (int thId = 0; thId < g->imagePixelBuffer.size(); thId++) {
                for (int i = 0; i < g->imagePixelBuffer[thId].size() / 4; i++) {
                    /*if (i == 20) {
                        std::cout << " ? " << std::endl;
                    }*/
                    int rC, gC, bC, aC;
                    rC = g->imagePixelBuffer[thId][i * 4 + 0];
                    gC = g->imagePixelBuffer[thId][i * 4 + 1];
                    bC = g->imagePixelBuffer[thId][i * 4 + 2];
                    aC = g->imagePixelBuffer[thId][i * 4 + 3];
                    int row;
                    int col;

                    row = i / (int)canvas_sz.x + (thId) * (g->imageHeight / g->threadCount);
                    col = i % (int)canvas_sz.x;

                    draw_list->AddRectFilled(ImVec2(canvas_p0.x + col, canvas_p0.y + row), ImVec2(canvas_p0.x + col + 1, canvas_p0.y + row + 1), IM_COL32(rC, gC, bC, aC));
                }
            }

            ImGui::End();
        }

        // 3. Show another simple window.
        if (show_another_window)
        {
            ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
            ImGui::Text("Hello from another window!");
            if (ImGui::Button("Close Me"))
                show_another_window = false;
            ImGui::End();
        }

        // Rendering
        ImGui::Render();

        FrameContext* frameCtx = WaitForNextFrameResources();
        UINT backBufferIdx = g_pSwapChain->GetCurrentBackBufferIndex();
        frameCtx->CommandAllocator->Reset();

        D3D12_RESOURCE_BARRIER barrier = {};
        barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
        barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
        barrier.Transition.pResource = g_mainRenderTargetResource[backBufferIdx];
        barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
        barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_PRESENT;
        barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_RENDER_TARGET;
        g_pd3dCommandList->Reset(frameCtx->CommandAllocator, NULL);
        g_pd3dCommandList->ResourceBarrier(1, &barrier);

        // Render Dear ImGui graphics
        const float clear_color_with_alpha[4] = { clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w };
        g_pd3dCommandList->ClearRenderTargetView(g_mainRenderTargetDescriptor[backBufferIdx], clear_color_with_alpha, 0, NULL);
        g_pd3dCommandList->OMSetRenderTargets(1, &g_mainRenderTargetDescriptor[backBufferIdx], FALSE, NULL);
        g_pd3dCommandList->SetDescriptorHeaps(1, &g_pd3dSrvDescHeap);
        ImGui_ImplDX12_RenderDrawData(ImGui::GetDrawData(), g_pd3dCommandList);
        barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_RENDER_TARGET;
        barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_PRESENT;
        g_pd3dCommandList->ResourceBarrier(1, &barrier);
        g_pd3dCommandList->Close();

        g_pd3dCommandQueue->ExecuteCommandLists(1, (ID3D12CommandList* const*)&g_pd3dCommandList);

        // Update and Render additional Platform Windows
        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
        {
            ImGui::UpdatePlatformWindows();
            ImGui::RenderPlatformWindowsDefault(NULL, (void*)g_pd3dCommandList);
        }

        g_pSwapChain->Present(1, 0); // Present with vsync
        g_pSwapChain->Present(0, 0); // Present without vsync

        UINT64 fenceValue = g_fenceLastSignaledValue + 1;
        g_pd3dCommandQueue->Signal(g_fence, fenceValue);
        g_fenceLastSignaledValue = fenceValue;
        frameCtx->FenceValue = fenceValue;
    }

    WaitForLastSubmittedFrame();

    // Cleanup
    ImGui_ImplDX12_Shutdown();
    ImGui_ImplWin32_Shutdown();
    ImGui::DestroyContext();

    CleanupDeviceD3D();
    ::DestroyWindow(hwnd);
    ::UnregisterClass(wc.lpszClassName, wc.hInstance);

    return 0;
}

// Helper functions

bool CreateDeviceD3D(HWND hWnd)
{
    // Setup swap chain
    DXGI_SWAP_CHAIN_DESC1 sd;
    {
        ZeroMemory(&sd, sizeof(sd));
        sd.BufferCount = NUM_BACK_BUFFERS;
        sd.Width = 0;
        sd.Height = 0;
        sd.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
        sd.Flags = DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT;
        sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
        sd.SampleDesc.Count = 1;
        sd.SampleDesc.Quality = 0;
        sd.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;
        sd.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED;
        sd.Scaling = DXGI_SCALING_STRETCH;
        sd.Stereo = FALSE;
    }

    // [DEBUG] Enable debug interface
#ifdef DX12_ENABLE_DEBUG_LAYER
    ID3D12Debug* pdx12Debug = NULL;
    if (SUCCEEDED(D3D12GetDebugInterface(IID_PPV_ARGS(&pdx12Debug))))
        pdx12Debug->EnableDebugLayer();
#endif

    // Create device
    D3D_FEATURE_LEVEL featureLevel = D3D_FEATURE_LEVEL_11_0;
    if (D3D12CreateDevice(NULL, featureLevel, IID_PPV_ARGS(&g_pd3dDevice)) != S_OK)
        return false;

    // [DEBUG] Setup debug interface to break on any warnings/errors
#ifdef DX12_ENABLE_DEBUG_LAYER
    if (pdx12Debug != NULL)
    {
        ID3D12InfoQueue* pInfoQueue = NULL;
        g_pd3dDevice->QueryInterface(IID_PPV_ARGS(&pInfoQueue));
        pInfoQueue->SetBreakOnSeverity(D3D12_MESSAGE_SEVERITY_ERROR, true);
        pInfoQueue->SetBreakOnSeverity(D3D12_MESSAGE_SEVERITY_CORRUPTION, true);
        pInfoQueue->SetBreakOnSeverity(D3D12_MESSAGE_SEVERITY_WARNING, true);
        pInfoQueue->Release();
        pdx12Debug->Release();
    }
#endif

    {
        D3D12_DESCRIPTOR_HEAP_DESC desc = {};
        desc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_RTV;
        desc.NumDescriptors = NUM_BACK_BUFFERS;
        desc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
        desc.NodeMask = 1;
        if (g_pd3dDevice->CreateDescriptorHeap(&desc, IID_PPV_ARGS(&g_pd3dRtvDescHeap)) != S_OK)
            return false;

        SIZE_T rtvDescriptorSize = g_pd3dDevice->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV);
        D3D12_CPU_DESCRIPTOR_HANDLE rtvHandle = g_pd3dRtvDescHeap->GetCPUDescriptorHandleForHeapStart();
        for (UINT i = 0; i < NUM_BACK_BUFFERS; i++)
        {
            g_mainRenderTargetDescriptor[i] = rtvHandle;
            rtvHandle.ptr += rtvDescriptorSize;
        }
    }

    {
        D3D12_DESCRIPTOR_HEAP_DESC desc = {};
        desc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV;
        desc.NumDescriptors = 1;
        desc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE;
        if (g_pd3dDevice->CreateDescriptorHeap(&desc, IID_PPV_ARGS(&g_pd3dSrvDescHeap)) != S_OK)
            return false;
    }

    {
        D3D12_COMMAND_QUEUE_DESC desc = {};
        desc.Type = D3D12_COMMAND_LIST_TYPE_DIRECT;
        desc.Flags = D3D12_COMMAND_QUEUE_FLAG_NONE;
        desc.NodeMask = 1;
        if (g_pd3dDevice->CreateCommandQueue(&desc, IID_PPV_ARGS(&g_pd3dCommandQueue)) != S_OK)
            return false;
    }

    for (UINT i = 0; i < NUM_FRAMES_IN_FLIGHT; i++)
        if (g_pd3dDevice->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&g_frameContext[i].CommandAllocator)) != S_OK)
            return false;

    if (g_pd3dDevice->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, g_frameContext[0].CommandAllocator, NULL, IID_PPV_ARGS(&g_pd3dCommandList)) != S_OK ||
        g_pd3dCommandList->Close() != S_OK)
        return false;

    if (g_pd3dDevice->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&g_fence)) != S_OK)
        return false;

    g_fenceEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
    if (g_fenceEvent == NULL)
        return false;

    {
        IDXGIFactory4* dxgiFactory = NULL;
        IDXGISwapChain1* swapChain1 = NULL;
        if (CreateDXGIFactory1(IID_PPV_ARGS(&dxgiFactory)) != S_OK)
            return false;
        if (dxgiFactory->CreateSwapChainForHwnd(g_pd3dCommandQueue, hWnd, &sd, NULL, NULL, &swapChain1) != S_OK)
            return false;
        if (swapChain1->QueryInterface(IID_PPV_ARGS(&g_pSwapChain)) != S_OK)
            return false;
        swapChain1->Release();
        dxgiFactory->Release();
        g_pSwapChain->SetMaximumFrameLatency(NUM_BACK_BUFFERS);
        g_hSwapChainWaitableObject = g_pSwapChain->GetFrameLatencyWaitableObject();
    }

    CreateRenderTarget();
    return true;
}

void CleanupDeviceD3D()
{
    CleanupRenderTarget();
    if (g_pSwapChain) { g_pSwapChain->SetFullscreenState(false, NULL); g_pSwapChain->Release(); g_pSwapChain = NULL; }
    if (g_hSwapChainWaitableObject != NULL) { CloseHandle(g_hSwapChainWaitableObject); }
    for (UINT i = 0; i < NUM_FRAMES_IN_FLIGHT; i++)
        if (g_frameContext[i].CommandAllocator) { g_frameContext[i].CommandAllocator->Release(); g_frameContext[i].CommandAllocator = NULL; }
    if (g_pd3dCommandQueue) { g_pd3dCommandQueue->Release(); g_pd3dCommandQueue = NULL; }
    if (g_pd3dCommandList) { g_pd3dCommandList->Release(); g_pd3dCommandList = NULL; }
    if (g_pd3dRtvDescHeap) { g_pd3dRtvDescHeap->Release(); g_pd3dRtvDescHeap = NULL; }
    if (g_pd3dSrvDescHeap) { g_pd3dSrvDescHeap->Release(); g_pd3dSrvDescHeap = NULL; }
    if (g_fence) { g_fence->Release(); g_fence = NULL; }
    if (g_fenceEvent) { CloseHandle(g_fenceEvent); g_fenceEvent = NULL; }
    if (g_pd3dDevice) { g_pd3dDevice->Release(); g_pd3dDevice = NULL; }

#ifdef DX12_ENABLE_DEBUG_LAYER
    IDXGIDebug1* pDebug = NULL;
    if (SUCCEEDED(DXGIGetDebugInterface1(0, IID_PPV_ARGS(&pDebug))))
    {
        pDebug->ReportLiveObjects(DXGI_DEBUG_ALL, DXGI_DEBUG_RLO_SUMMARY);
        pDebug->Release();
    }
#endif
}

void CreateRenderTarget()
{
    for (UINT i = 0; i < NUM_BACK_BUFFERS; i++)
    {
        ID3D12Resource* pBackBuffer = NULL;
        g_pSwapChain->GetBuffer(i, IID_PPV_ARGS(&pBackBuffer));
        g_pd3dDevice->CreateRenderTargetView(pBackBuffer, NULL, g_mainRenderTargetDescriptor[i]);
        g_mainRenderTargetResource[i] = pBackBuffer;
    }
}

void CleanupRenderTarget()
{
    WaitForLastSubmittedFrame();

    for (UINT i = 0; i < NUM_BACK_BUFFERS; i++)
        if (g_mainRenderTargetResource[i]) { g_mainRenderTargetResource[i]->Release(); g_mainRenderTargetResource[i] = NULL; }
}

void WaitForLastSubmittedFrame()
{
    FrameContext* frameCtx = &g_frameContext[g_frameIndex % NUM_FRAMES_IN_FLIGHT];

    UINT64 fenceValue = frameCtx->FenceValue;
    if (fenceValue == 0)
        return; // No fence was signaled

    frameCtx->FenceValue = 0;
    if (g_fence->GetCompletedValue() >= fenceValue)
        return;

    g_fence->SetEventOnCompletion(fenceValue, g_fenceEvent);
    WaitForSingleObject(g_fenceEvent, INFINITE);
}

FrameContext* WaitForNextFrameResources()
{
    UINT nextFrameIndex = g_frameIndex + 1;
    g_frameIndex = nextFrameIndex;

    HANDLE waitableObjects[] = { g_hSwapChainWaitableObject, NULL };
    DWORD numWaitableObjects = 1;

    FrameContext* frameCtx = &g_frameContext[nextFrameIndex % NUM_FRAMES_IN_FLIGHT];
    UINT64 fenceValue = frameCtx->FenceValue;
    if (fenceValue != 0) // means no fence was signaled
    {
        frameCtx->FenceValue = 0;
        g_fence->SetEventOnCompletion(fenceValue, g_fenceEvent);
        waitableObjects[1] = g_fenceEvent;
        numWaitableObjects = 2;
    }

    WaitForMultipleObjects(numWaitableObjects, waitableObjects, TRUE, INFINITE);

    return frameCtx;
}

// Forward declare message handler from imgui_impl_win32.cpp
extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);

// Win32 message handler
// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
// Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam))
        return true;

    switch (msg)
    {
    case WM_SIZE:
        if (g_pd3dDevice != NULL && wParam != SIZE_MINIMIZED)
        {
            WaitForLastSubmittedFrame();
            CleanupRenderTarget();
            HRESULT result = g_pSwapChain->ResizeBuffers(0, (UINT)LOWORD(lParam), (UINT)HIWORD(lParam), DXGI_FORMAT_UNKNOWN, DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT);
            assert(SUCCEEDED(result) && "Failed to resize swapchain.");
            CreateRenderTarget();
        }
        return 0;
    case WM_SYSCOMMAND:
        if ((wParam & 0xfff0) == SC_KEYMENU) // Disable ALT application menu
            return 0;
        break;
    case WM_DESTROY:
        ::PostQuitMessage(0);
        return 0;
    }
    return ::DefWindowProc(hWnd, msg, wParam, lParam);
}