ImGuiContext.cpp

#include "ImGuiContext.h"

#include "imgui_impl_dx11.h"
#include "imgui_impl_win32.h"

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <tchar.h>

#include <d3d.h>
#include <d3d11.h>
#include <d3dcompiler.h>
#include <dxgi.h>

#include <stdio.h>

#include "imgui.h"
#include "imgui_internal.h"

#pragma comment(lib, "d3d11.lib")
#pragma comment(lib, "d3dcompiler.lib")
#pragma comment(lib, "dxgi.lib")
#pragma comment(lib, "imm32.lib")

extern HWND g_hWnd;
extern ID3D11DeviceContext* g_pd3dDeviceContext;
extern ID3D11Device* g_pd3dDevice;
extern IDXGIFactory1* g_pFactory;
static ID3D11RenderTargetView* g_mainRenderTargetView;

//extern LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
extern void ImGui_ImplWin32_InitPlatformInterface();
extern void ImGui_ImplDX11_InitPlatformInterface();

namespace ImGuiCLI
{
    ImGuiContext::ImGuiContext(System::IntPtr hwnd, System::IntPtr devicePtr, System::IntPtr mainDeviceContext, System::IntPtr renderTarget)
    {
        g_hWnd = (HWND)hwnd.ToInt64();
        g_pd3dDeviceContext = (ID3D11DeviceContext*)mainDeviceContext.ToPointer();
        g_pd3dDevice = (ID3D11Device*)devicePtr.ToPointer();

        ImGui::CreateContext();

        ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);

        g_mainRenderTargetView = (ID3D11RenderTargetView*)renderTarget.ToPointer();

        // Setup ImGui binding
        ImGuiIO& io = ImGui::GetIO(); (void)io;
        io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;
        io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoTaskBarIcons;
        io.ConfigFlags |= ImGuiConfigFlags_DpiEnableScaleFonts;
        io.ConfigFlags |= ImGuiConfigFlags_DpiEnableScaleViewports;
        io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls

        // Setup back-end capabilities flags
        io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
        io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;    // We can create multi-viewports on the Platform side (optional)
        io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can set io.MouseHoveredViewport correctly (optional, not easy)
        
        ImGuiViewport* main_viewport = ImGui::GetMainViewport();
        main_viewport->PlatformHandle = (void*)g_hWnd;
        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
            ImGui_ImplWin32_InitPlatformInterface();
        //ImGui::GetIO().ImeWindowHandle = g_hWnd;

        // Keyboard mapping. ImGui will use those indices to peek into the io.KeysDown[] array that we will update during the application lifetime.
        io.KeyMap[ImGuiKey_Tab] = VK_TAB;
        io.KeyMap[ImGuiKey_LeftArrow] = VK_LEFT;
        io.KeyMap[ImGuiKey_RightArrow] = VK_RIGHT;
        io.KeyMap[ImGuiKey_UpArrow] = VK_UP;
        io.KeyMap[ImGuiKey_DownArrow] = VK_DOWN;
        io.KeyMap[ImGuiKey_PageUp] = VK_PRIOR;
        io.KeyMap[ImGuiKey_PageDown] = VK_NEXT;
        io.KeyMap[ImGuiKey_Home] = VK_HOME;
        io.KeyMap[ImGuiKey_End] = VK_END;
        io.KeyMap[ImGuiKey_Insert] = VK_INSERT;
        io.KeyMap[ImGuiKey_Delete] = VK_DELETE;
        io.KeyMap[ImGuiKey_Backspace] = VK_BACK;
        io.KeyMap[ImGuiKey_Space] = VK_SPACE;
        io.KeyMap[ImGuiKey_Enter] = VK_RETURN;
        io.KeyMap[ImGuiKey_Escape] = VK_ESCAPE;
        io.KeyMap[ImGuiKey_A] = 'A';
        io.KeyMap[ImGuiKey_C] = 'C';
        io.KeyMap[ImGuiKey_V] = 'V';
        io.KeyMap[ImGuiKey_X] = 'X';
        io.KeyMap[ImGuiKey_Y] = 'Y';
        io.KeyMap[ImGuiKey_Z] = 'Z';

        io.Fonts->AddFontDefault();

        // Setup back-end capabilities flags
        io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;    // We can create multi-viewports on the Renderer side (optional)
        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
            ImGui_ImplDX11_InitPlatformInterface();

        // Setup style
        ImGui::StyleColorsDark();
        //ImGui::StyleColorsClassic();
        ImGuiStyle& style = ImGui::GetStyle();
        style.WindowRounding = 0.0f;

        ImGui_ImplDX11_CreateDeviceObjects();
    }

    ImGuiContext::~ImGuiContext()
    {
    }

    void ImGuiContext::NewFrame(int w, int h)
    {
        extern ID3D11SamplerState* g_pFontSampler;
        if (!g_pFontSampler)
            ImGui_ImplDX11_CreateDeviceObjects();
        auto& io = ImGui::GetIO();
        io.DisplaySize.x = w;
        io.DisplaySize.y = h;
        extern void ImGui_ImplDX11_NewFrame();
        extern void ImGui_ImplWin32_NewFrame();
        ImGui_ImplDX11_NewFrame();
        ImGui_ImplWin32_NewFrame();
    }

    void ImGuiContext::Shutdown()
    {
        extern void ImGui_ImplDX11_ShutdownPlatformInterface();
        extern void ImGui_ImplDX11_InvalidateDeviceObjects();
        ImGui_ImplDX11_ShutdownPlatformInterface();
        ImGui_ImplDX11_InvalidateDeviceObjects();

        extern void ImGui_ImplWin32_ShutdownPlatformInterface();
        ImGui_ImplWin32_ShutdownPlatformInterface();

        ImGui::DestroyContext();
    }

    void ImGuiContext::RenderNoDraw()
    {
        auto& io = ImGui::GetIO();
        ImGui::Render();
        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
            ImGui::UpdatePlatformWindows();
    }

    void ImGuiContext::RenderAndDraw(System::IntPtr renderTarget)
    {
        auto& io = ImGui::GetIO();
        g_mainRenderTargetView = (ID3D11RenderTargetView*)renderTarget.ToPointer();
        extern void ImGui_ImplDX11_RenderDrawData(ImDrawData*);
        // Rendering
        ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
        
        RecordState();
        
        ImGui::Render();
        ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());

        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
        {
            ImGui::UpdatePlatformWindows();
            ImGui::RenderPlatformWindowsDefault();
        }

        RestoreState();
    }

    void ImGuiContext::Draw(System::IntPtr renderTarget)
    {
        g_mainRenderTargetView = (ID3D11RenderTargetView*)renderTarget.ToPointer();
        extern void ImGui_ImplDX11_RenderDrawData(ImDrawData*);

        RecordState();

        ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
        if (ImGui::GetIO().ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
            ImGui::RenderPlatformWindowsDefault();
        
        RestoreState();
    }

    void ImGuiContext::ResizeMain(int width, int height, System::IntPtr mainRenderTarget)
    {

    }
    
    static ID3D11RenderTargetView* previousTargets[4];
    static ID3D11DepthStencilView* previousDepth;
    static unsigned previousNumViewports = 0;
    static D3D11_VIEWPORT previousViewports[4];
    //static ID3DD
    void ImGuiContext::RecordState()
    {
        g_pd3dDeviceContext->OMGetRenderTargets(4, previousTargets, &previousDepth);
        g_pd3dDeviceContext->RSGetViewports(&previousNumViewports, nullptr);
        g_pd3dDeviceContext->RSGetViewports(&previousNumViewports, previousViewports);
    }
    void ImGuiContext::RestoreState()
    {
        // count number of non null views, passing a bad count will mess stuff up
        int targetCt = 0;
        for (int i = 0; i < 4; ++i)
            if (previousTargets[i] != nullptr)
                ++targetCt;
        g_pd3dDeviceContext->OMSetRenderTargets(targetCt, previousTargets, previousDepth);
        for (int i = 0; i < 4; ++i)
        {
            if (previousTargets[i] != nullptr)
                previousTargets[i]->Release();
            previousTargets[i] = nullptr;
        }
        if (previousNumViewports)
            g_pd3dDeviceContext->RSSetViewports(previousNumViewports, previousViewports);
    }
}