text: // ImGui Win32 + DirectX9 binding
  // In this binding, ImTextureID is used to store a 'LPDIRECT3DTEXTURE9' 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
  
  #include <imgui.h>
  #include "imgui_impl_dx9.h"
  
  // DirectX
  #include <d3d9.h>
  #define DIRECTINPUT_VERSION 0x0800
  #include <dinput.h>
  
  // Data
  static HWND                     g_hWnd = 0;
  static INT64                    g_Time = 0;
  static INT64                    g_TicksPerSecond = 0;
  static LPDIRECT3DDEVICE9        g_pd3dDevice = NULL;
  static LPDIRECT3DVERTEXBUFFER9  g_pVB = NULL;
  static LPDIRECT3DINDEXBUFFER9   g_pIB = NULL;
  static LPDIRECT3DTEXTURE9       g_FontTexture = NULL;
  static int                      g_VertexBufferSize = 5000, g_IndexBufferSize = 10000;
  
  struct CUSTOMVERTEX
  {
      float    pos[3];
      D3DCOLOR col;
      float    uv[2];
  };
  #define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ|D3DFVF_DIFFUSE|D3DFVF_TEX1)
  
  // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
  // If text or lines are blurry when integrating ImGui in your engine:
  // - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
  void ImGui_ImplDX9_RenderDrawLists(ImDrawData* draw_data)
  {
      // Avoid rendering when minimized
      ImGuiIO& io = ImGui::GetIO();
      if (io.DisplaySize.x <= 0.0f || io.DisplaySize.y <= 0.0f)
          return;
  
      // Create and grow buffers if needed
      if (!g_pVB || g_VertexBufferSize < draw_data->TotalVtxCount)
      {
          if (g_pVB) { g_pVB->Release(); g_pVB = NULL; }
          g_VertexBufferSize = draw_data->TotalVtxCount + 5000;
          if (g_pd3dDevice->CreateVertexBuffer(g_VertexBufferSize * sizeof(CUSTOMVERTEX), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &g_pVB, NULL) < 0)
              return;
      }
      if (!g_pIB || g_IndexBufferSize < draw_data->TotalIdxCount)
      {
          if (g_pIB) { g_pIB->Release(); g_pIB = NULL; }
          g_IndexBufferSize = draw_data->TotalIdxCount + 10000;
          if (g_pd3dDevice->CreateIndexBuffer(g_IndexBufferSize * sizeof(ImDrawIdx), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, sizeof(ImDrawIdx) == 2 ? D3DFMT_INDEX16 : D3DFMT_INDEX32, D3DPOOL_DEFAULT, &g_pIB, NULL) < 0)
              return;
      }
  
      // Backup the DX9 state
      IDirect3DStateBlock9* d3d9_state_block = NULL;
      if (g_pd3dDevice->CreateStateBlock(D3DSBT_ALL, &d3d9_state_block) < 0)
          return;
  
      // Copy and convert all vertices into a single contiguous buffer
      CUSTOMVERTEX* vtx_dst;
      ImDrawIdx* idx_dst;
      if (g_pVB->Lock(0, (UINT)(draw_data->TotalVtxCount * sizeof(CUSTOMVERTEX)), (void**)&vtx_dst, D3DLOCK_DISCARD) < 0)
          return;
      if (g_pIB->Lock(0, (UINT)(draw_data->TotalIdxCount * sizeof(ImDrawIdx)), (void**)&idx_dst, D3DLOCK_DISCARD) < 0)
          return;
      for (int n = 0; n < draw_data->CmdListsCount; n++)
      {
          const ImDrawList* cmd_list = draw_data->CmdLists[n];
          const ImDrawVert* vtx_src = cmd_list->VtxBuffer.Data;
          for (int i = 0; i < cmd_list->VtxBuffer.Size; i++)
          {
              vtx_dst->pos[0] = vtx_src->pos.x;
              vtx_dst->pos[1] = vtx_src->pos.y;
              vtx_dst->pos[2] = 0.0f;
              vtx_dst->col = (vtx_src->col & 0xFF00FF00) | ((vtx_src->col & 0xFF0000)>>16) | ((vtx_src->col & 0xFF) << 16);     // RGBA --> ARGB for DirectX9
              vtx_dst->uv[0] = vtx_src->uv.x;
              vtx_dst->uv[1] = vtx_src->uv.y;
              vtx_dst++;
              vtx_src++;
          }
          memcpy(idx_dst, cmd_list->IdxBuffer.Data, cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx));
          idx_dst += cmd_list->IdxBuffer.Size;
      }
      g_pVB->Unlock();
      g_pIB->Unlock();
      g_pd3dDevice->SetStreamSource(0, g_pVB, 0, sizeof(CUSTOMVERTEX));
      g_pd3dDevice->SetIndices(g_pIB);
      g_pd3dDevice->SetFVF(D3DFVF_CUSTOMVERTEX);
  
      // Setup render state: fixed-pipeline, alpha-blending, no face culling, no depth testing
      g_pd3dDevice->SetPixelShader(NULL);
      g_pd3dDevice->SetVertexShader(NULL);
      g_pd3dDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
      g_pd3dDevice->SetRenderState(D3DRS_LIGHTING, false);
      g_pd3dDevice->SetRenderState(D3DRS_ZENABLE, false);
      g_pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
      g_pd3dDevice->SetRenderState(D3DRS_ALPHATESTENABLE, false);
      g_pd3dDevice->SetRenderState(D3DRS_BLENDOP, D3DBLENDOP_ADD);
      g_pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
      g_pd3dDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
      g_pd3dDevice->SetRenderState(D3DRS_SCISSORTESTENABLE, true);
      g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE);
      g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
      g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE);
      g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE);
      g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
      g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE);
      g_pd3dDevice->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
      g_pd3dDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
  
      // Setup orthographic projection matrix
      // Being agnostic of whether <d3dx9.h> or <DirectXMath.h> can be used, we aren't relying on D3DXMatrixIdentity()/D3DXMatrixOrthoOffCenterLH() or DirectX::XMMatrixIdentity()/DirectX::XMMatrixOrthographicOffCenterLH()
      {
          const float L = 0.5f, R = io.DisplaySize.x+0.5f, T = 0.5f, B = io.DisplaySize.y+0.5f;
          D3DMATRIX mat_identity = { { 1.0f, 0.0f, 0.0f, 0.0f,  0.0f, 1.0f, 0.0f, 0.0f,  0.0f, 0.0f, 1.0f, 0.0f,  0.0f, 0.0f, 0.0f, 1.0f } };
          D3DMATRIX mat_projection =
          {
              2.0f/(R-L),   0.0f,         0.0f,  0.0f,
              0.0f,         2.0f/(T-B),   0.0f,  0.0f,
              0.0f,         0.0f,         0.5f,  0.0f,
              (L+R)/(L-R),  (T+B)/(B-T),  0.5f,  1.0f,
          };
          g_pd3dDevice->SetTransform(D3DTS_WORLD, &mat_identity);
          g_pd3dDevice->SetTransform(D3DTS_VIEW, &mat_identity);
          g_pd3dDevice->SetTransform(D3DTS_PROJECTION, &mat_projection);
      }
  
      // Render command lists
      int vtx_offset = 0;
      int idx_offset = 0;
      for (int n = 0; n < draw_data->CmdListsCount; n++)
      {
          const ImDrawList* cmd_list = draw_data->CmdLists[n];
          for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
          {
              const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
              if (pcmd->UserCallback)
              {
                  pcmd->UserCallback(cmd_list, pcmd);
              }
              else
              {
                  const RECT r = { (LONG)pcmd->ClipRect.x, (LONG)pcmd->ClipRect.y, (LONG)pcmd->ClipRect.z, (LONG)pcmd->ClipRect.w };
                  g_pd3dDevice->SetTexture(0, (LPDIRECT3DTEXTURE9)pcmd->TextureId);
                  g_pd3dDevice->SetScissorRect(&r);
                  g_pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, vtx_offset, 0, (UINT)cmd_list->VtxBuffer.Size, idx_offset, pcmd->ElemCount/3);
              }
              idx_offset += pcmd->ElemCount;
          }
          vtx_offset += cmd_list->VtxBuffer.Size;
      }
  
      // Restore the DX9 state
      d3d9_state_block->Apply();
      d3d9_state_block->Release();
  }
  
  IMGUI_API LRESULT ImGui_ImplDX9_WndProcHandler(HWND, UINT msg, WPARAM wParam, LPARAM lParam)
  {
      ImGuiIO& io = ImGui::GetIO();
      switch (msg)
      {
      case WM_LBUTTONDOWN:
          io.MouseDown[0] = true;
          return true;
      case WM_LBUTTONUP:
          io.MouseDown[0] = false;
          return true;
      case WM_RBUTTONDOWN:
          io.MouseDown[1] = true;
          return true;
      case WM_RBUTTONUP:
          io.MouseDown[1] = false;
          return true;
      case WM_MBUTTONDOWN:
          io.MouseDown[2] = true;
          return true;
      case WM_MBUTTONUP:
          io.MouseDown[2] = false;
          return true;
      case WM_MOUSEWHEEL:
          io.MouseWheel += GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
          return true;
      case WM_MOUSEMOVE:
          io.MousePos.x = (signed short)(lParam);
          io.MousePos.y = (signed short)(lParam >> 16);
          return true;
      case WM_KEYDOWN:
          if (wParam < 256)
              io.KeysDown[wParam] = 1;
          return true;
      case WM_KEYUP:
          if (wParam < 256)
              io.KeysDown[wParam] = 0;
          return true;
      case WM_CHAR:
          // You can also use ToAscii()+GetKeyboardState() to retrieve characters.
          if (wParam > 0 && wParam < 0x10000)
              io.AddInputCharacter((unsigned short)wParam);
          return true;
      }
      return 0;
  }
  
  bool    ImGui_ImplDX9_Init(void* hwnd, IDirect3DDevice9* device)
  {
      g_hWnd = (HWND)hwnd;
      g_pd3dDevice = device;
  
      if (!QueryPerformanceFrequency((LARGE_INTEGER *)&g_TicksPerSecond))
          return false;
      if (!QueryPerformanceCounter((LARGE_INTEGER *)&g_Time))
          return false;
  
      ImGuiIO& io = ImGui::GetIO();
      io.KeyMap[ImGuiKey_Tab] = VK_TAB;                       // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array that we will update during the application lifetime.
      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_Delete] = VK_DELETE;
      io.KeyMap[ImGuiKey_Backspace] = VK_BACK;
      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.RenderDrawListsFn = ImGui_ImplDX9_RenderDrawLists;   // Alternatively you can set this to NULL and call ImGui::GetDrawData() after ImGui::Render() to get the same ImDrawData pointer.
      io.ImeWindowHandle = g_hWnd;
  
      return true;
  }
  
  void ImGui_ImplDX9_Shutdown()
  {
      ImGui_ImplDX9_InvalidateDeviceObjects();
      ImGui::Shutdown();
      g_pd3dDevice = NULL;
      g_hWnd = 0;
  }
  
  static bool ImGui_ImplDX9_CreateFontsTexture()
  {
      // Build texture atlas
      ImGuiIO& io = ImGui::GetIO();
      unsigned char* pixels;
      int width, height, bytes_per_pixel;
      io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height, &bytes_per_pixel);
  
      // Upload texture to graphics system
      g_FontTexture = NULL;
      if (g_pd3dDevice->CreateTexture(width, height, 1, D3DUSAGE_DYNAMIC, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &g_FontTexture, NULL) < 0)
          return false;
      D3DLOCKED_RECT tex_locked_rect;
      if (g_FontTexture->LockRect(0, &tex_locked_rect, NULL, 0) != D3D_OK)
          return false;
      for (int y = 0; y < height; y++)
          memcpy((unsigned char *)tex_locked_rect.pBits + tex_locked_rect.Pitch * y, pixels + (width * bytes_per_pixel) * y, (width * bytes_per_pixel));
      g_FontTexture->UnlockRect(0);
  
      // Store our identifier
      io.Fonts->TexID = (void *)g_FontTexture;
  
      return true;
  }
  
  bool ImGui_ImplDX9_CreateDeviceObjects()
  {
      if (!g_pd3dDevice)
          return false;
      if (!ImGui_ImplDX9_CreateFontsTexture())
          return false;
      return true;
  }
  
  void ImGui_ImplDX9_InvalidateDeviceObjects()
  {
      if (!g_pd3dDevice)
          return;
      if (g_pVB)
      {
          g_pVB->Release();
          g_pVB = NULL;
      }
      if (g_pIB)
      {
          g_pIB->Release();
          g_pIB = NULL;
      }
      if (LPDIRECT3DTEXTURE9 tex = (LPDIRECT3DTEXTURE9)ImGui::GetIO().Fonts->TexID)
      {
          tex->Release();
          ImGui::GetIO().Fonts->TexID = 0;
      }
      g_FontTexture = NULL;
  }
  
  void ImGui_ImplDX9_NewFrame()
  {
      if (!g_FontTexture)
          ImGui_ImplDX9_CreateDeviceObjects();
  
      ImGuiIO& io = ImGui::GetIO();
  
      // Setup display size (every frame to accommodate for window resizing)
      RECT rect;
      GetClientRect(g_hWnd, &rect);
      io.DisplaySize = ImVec2((float)(rect.right - rect.left), (float)(rect.bottom - rect.top));
  
      // Setup time step
      INT64 current_time;
      QueryPerformanceCounter((LARGE_INTEGER *)&current_time);
      io.DeltaTime = (float)(current_time - g_Time) / g_TicksPerSecond;
      g_Time = current_time;
  
      // Read keyboard modifiers inputs
      io.KeyCtrl = (GetKeyState(VK_CONTROL) & 0x8000) != 0;
      io.KeyShift = (GetKeyState(VK_SHIFT) & 0x8000) != 0;
      io.KeyAlt = (GetKeyState(VK_MENU) & 0x8000) != 0;
      io.KeySuper = false;
      // io.KeysDown : filled by WM_KEYDOWN/WM_KEYUP events
      // io.MousePos : filled by WM_MOUSEMOVE events
      // io.MouseDown : filled by WM_*BUTTON* events
      // io.MouseWheel : filled by WM_MOUSEWHEEL events
  
      // Hide OS mouse cursor if ImGui is drawing it
      if (io.MouseDrawCursor)
          SetCursor(NULL);
  
      // Start the frame
      ImGui::NewFrame();
  }
  