Examples: Comments, bits of documentation

examples/imgui_impl_allegro5.cpp

@@ -10,9 +10,8 @@
 //  [ ] Renderer: The renderer is suboptimal as we need to unindex our buffers and convert the format of vertices.
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui, Original Allegro 5 code by @birthggd
-// https://github.com/ocornut/imgui, Original code by @birthggd
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)

examples/imgui_impl_allegro5.h

@@ -9,9 +9,8 @@
 //  [ ] Platform: Missing clipboard support via al_set_clipboard_text/al_clipboard_has_text.
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui, Original Allegro 5 code by @birthggd
-// https://github.com/ocornut/imgui, Original code by @birthggd
 
 #pragma once
 

examples/imgui_impl_dx10.cpp

@@ -5,8 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG 

examples/imgui_impl_dx10.h

@@ -5,8 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 struct ID3D10Device;

examples/imgui_impl_dx11.cpp

@@ -5,8 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG

examples/imgui_impl_dx11.h

@@ -5,8 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 struct ID3D11Device;

examples/imgui_impl_dx12.cpp

@@ -7,8 +7,7 @@
 //  [ ] 64-bit only for now! (Because sizeof(ImTextureId) == sizeof(void*)). See github.com/ocornut/imgui/pull/301
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG

examples/imgui_impl_dx12.h

@@ -7,8 +7,7 @@
 //  [ ] 64-bit only for now! (Because sizeof(ImTextureId) == sizeof(void*)). See github.com/ocornut/imgui/pull/301
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 enum DXGI_FORMAT;

examples/imgui_impl_dx9.cpp

@@ -5,8 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG 

examples/imgui_impl_dx9.h

@@ -5,8 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 struct IDirect3DDevice9;

examples/imgui_impl_freeglut.cpp

@@ -5,8 +5,7 @@
 //  [ ] Platform: GLUT is unable to distinguish e.g. Backspace from CTRL+H or TAB from CTRL+I
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG

examples/imgui_impl_freeglut.h

@@ -5,8 +5,7 @@
 //  [ ] Platform: GLUT is unable to distinguish e.g. Backspace from CTRL+H or TAB from CTRL+I
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 IMGUI_IMPL_API bool     ImGui_ImplFreeGLUT_Init();

examples/imgui_impl_glfw.cpp

@@ -9,8 +9,7 @@
 //  [X] Platform: Keyboard arrays indexed using GLFW_KEY_* codes, e.g. ImGui::IsKeyPressed(GLFW_KEY_SPACE).
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG

examples/imgui_impl_glfw.h

@@ -9,8 +9,7 @@
 //  [X] Platform: Keyboard arrays indexed using GLFW_KEY_* codes, e.g. ImGui::IsKeyPressed(GLFW_KEY_SPACE).
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // About GLSL version:

examples/imgui_impl_marmalade.cpp

@@ -1,16 +1,13 @@
 // ImGui Renderer + Platform Binding for: Marmalade + IwGx
+// Marmalade code: Copyright (C) 2015 by Giovanni Zito (this file is part of ImGui)
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'CIwTexture*' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
-// Copyright (C) 2015 by Giovanni Zito
-// This file is part of ImGui
-
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_Marmalade_RenderDrawData() in the .h file so you can call it yourself.

examples/imgui_impl_marmalade.h

@@ -4,8 +4,7 @@
 //  [X] Renderer: User texture binding. Use 'CIwTexture*' as ImTextureID. 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // Copyright (C) 2015 by Giovanni Zito

examples/imgui_impl_opengl2.cpp

@@ -4,6 +4,10 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. 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 are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
 // **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
 // **Prefer using the code in imgui_impl_opengl3.cpp**
 // This code is mostly provided as a reference to learn how ImGui integration works, because it is shorter to read.

examples/imgui_impl_opengl2.h

@@ -4,6 +4,10 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. 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 are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
 // **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
 // **Prefer using the code in imgui_impl_opengl3.cpp**
 // This code is mostly provided as a reference to learn how ImGui integration works, because it is shorter to read.

examples/imgui_impl_opengl3.cpp

@@ -5,6 +5,10 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. 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 are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
 // CHANGELOG 
 // (minor and older changes stripped away, please see git history for details)
 //  2018-06-08: Misc: Extracted imgui_impl_opengl3.cpp/.h away from the old combined GLFW/SDL+OpenGL3 examples.

examples/imgui_impl_opengl3.h

@@ -5,6 +5,10 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. 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 are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
 // About GLSL version:
 // The 'glsl_version' initialization parameter defaults to "#version 150" if NULL.
 // Only override if your GL version doesn't handle this GLSL version. Keep NULL if unsure!

examples/imgui_impl_sdl.cpp

@@ -10,8 +10,7 @@
 //  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG

examples/imgui_impl_sdl.h

@@ -10,8 +10,7 @@
 //  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
 
 // 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 dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 struct SDL_Window;

examples/imgui_impl_vulkan.cpp

@@ -5,8 +5,7 @@
 //  [ ] Renderer: User texture binding. Changes of ImTextureID aren't supported by this binding! See https://github.com/ocornut/imgui/pull/914
 
 // 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 5 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXX_CreateFontsTexture(), ImGui_ImplXXXX_NewFrame(), ImGui_ImplXXXX_Render() and ImGui_ImplXXXX_Shutdown().
+// If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 // CHANGELOG

examples/imgui_impl_vulkan.h

@@ -5,8 +5,7 @@
 //  [ ] Renderer: User texture binding. Changes of ImTextureID aren't supported by this binding! See https://github.com/ocornut/imgui/pull/914
 
 // 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 5 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXX_CreateFontsTexture(), ImGui_ImplXXXX_NewFrame(), ImGui_ImplXXXX_Render() and ImGui_ImplXXXX_Shutdown().
+// If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
 // https://github.com/ocornut/imgui
 
 #include <vulkan/vulkan.h>

imgui.cpp

@@ -120,34 +120,73 @@
  - Refer to the bindings and demo applications in the examples/ folder for instruction on how to setup your code.
 
  THIS IS HOW A SIMPLE APPLICATION MAY LOOK LIKE
+ EXHIBIT 1: USING THE EXAMPLE BINDINGS (imgui_impl_XXX.cpp files from the examples/ folder)
 
-     // Application init
+     // Application init: create a dear imgui context, setup some options, load fonts
-     // Create a context
      ImGui::CreateContext();
      ImGuiIO& io = ImGui::GetIO();
+     // TODO: Set optional io.ConfigFlags values, e.g. 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard' to enable keyboard controls
      // TODO: Fill optional settings of the io structure later.
-     // TODO: Load fonts if you don't want to use the default font.
+     // TODO: Load TTF/OTF fonts if you don't want to use the default font.
+
+     // Initialize helper Platform and Renderer bindings (here we are using imgui_impl_win32 and imgui_impl_dx11)
+     ImGui_ImplWin32_Init(hwnd);
+     ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);
+
+     // Application main loop
+     while (true)
+     {
+         // Feed inputs to dear imgui, start new frame
+         ImGui_ImplDX11_NewFrame();
+         ImGui_ImplWin32_NewFrame();
+         ImGui::NewFrame();
+
+         // Any application code here
+         ImGui::Text("Hello, world!");
+
+         // Render dear imgui into screen
+         ImGui::Render();
+         ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
+         g_pSwapChain->Present(1, 0);
+     }
+     
+     // Shutdown
+     ImGui_ImplDX11_Shutdown();
+     ImGui_ImplWin32_Shutdown();
+     ImGui::DestroyContext();
+
+ THIS IS HOW A SIMPLE APPLICATION MAY LOOK LIKE
+ EXHIBIT 2: IMPLEMENTING CUSTOM BINDING / CUSTOM ENGINE
+
+     // Application init: create a dear imgui context, setup some options, load fonts
+     ImGui::CreateContext();
+     ImGuiIO& io = ImGui::GetIO();
+     // TODO: Set optional io.ConfigFlags values, e.g. 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard' to enable keyboard controls
+     // TODO: Fill optional settings of the io structure later.
+     // TODO: Load TTF/OTF fonts if you don't want to use the default font.
 
      // Build and load the texture atlas into a texture
-     unsigned char* pixels = NULL;
+     // (In the examples/ app this is usually done within the ImGui_ImplXXX_Init() function from one of the demo Renderer)
      int width, height;
+     unsigned char* pixels = NULL;
      io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
+
      // At this point you've got the texture data and you need to upload that your your graphic system:
+     // After we have created the texture, store its pointer/identifier (_in whichever format your engine uses_) in 'io.Fonts->TexID'.
+     // This will be passed back to your via the renderer. Basically ImTextureID == void*. Read FAQ below for details about ImTextureID.
      MyTexture* texture = MyEngine::CreateTextureFromMemoryPixels(pixels, width, height, TEXTURE_TYPE_RGBA32)
-     // Store your texture pointer/identifier (in whatever formatyour engine uses) in 'io.Fonts->TexID'. 
-     // This will be passed back to your via the renderer. Read FAQ for details about ImTextureID.
      io.Fonts->TexID = (void*)texture;
 
      // Application main loop
      while (true)
      {
-        // Setup low-level inputs (e.g. on Win32, GetKeyboardState(), or write to those fields from your Windows message loop handlers, etc.)
+        // Setup low-level inputs, e.g. on Win32: calling GetKeyboardState(), or write to those fields from your Windows message handlers, etc.
-        ImGuiIO& io = ImGui::GetIO();
+        // (In the examples/ app this is usually done within the ImGui_ImplXXX_NewFrame() function from one of the demo Platform bindings)
-        io.DeltaTime = 1.0f/60.0f;
+        io.DeltaTime = 1.0f/60.0f;              // set the time elapsed since the previous frame (in seconds)
-        io.DisplaySize.x = 1920.0f;
+        io.DisplaySize.x = 1920.0f;             // set the current display width
-        io.DisplaySize.y = 1280.0f;
+        io.DisplaySize.y = 1280.0f;             // set the current display height here
-        io.MousePos = my_mouse_pos;
+        io.MousePos = my_mouse_pos;             // set the mouse position
-        io.MouseDown[0] = my_mouse_buttons[0];
+        io.MouseDown[0] = my_mouse_buttons[0];  // set the mouse button states
         io.MouseDown[1] = my_mouse_buttons[1];
 
         // Call NewFrame(), after this point you can use ImGui::* functions anytime
@@ -163,7 +202,8 @@
         // (You want to try calling EndFrame/Render as late as you can, to be able to use imgui in your own game rendering code)
         ImGui::EndFrame();
         ImGui::Render();
-        MyImGuiRenderFunction(ImGui::GetDrawData());
+        ImDrawData* draw_data = ImGui::GetDrawData();
+        MyImGuiRenderFunction(draw_data);
         SwapBuffers();
      }