setupDearIMGUI

# Using Dear ImGui to Show FPS Overlay in OpenGL

This guide outlines the steps to integrate Dear ImGui into your OpenGL project and display the FPS in the top right corner.

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## 1. Add Dear ImGui to Your Project

- Download ImGui from [https://github.com/ocornut/imgui](https://github.com/ocornut/imgui).
- Add the following files to your build:
  - `imgui.cpp`, `imgui_draw.cpp`, `imgui_tables.cpp`, `imgui_widgets.cpp`, `imgui_demo.cpp`
  - Backends: `imgui_impl_glfw.cpp`, `imgui_impl_opengl3.cpp`
- Include the headers in your project.

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## 2. Initialize ImGui

In your initialization code (after creating your OpenGL context and window):

```cpp
IMGUI_CHECKVERSION();
ImGui::CreateContext();
ImGuiIO& io = ImGui::GetIO(); (void)io;
ImGui::StyleColorsDark();
ImGui_ImplGlfw_InitForOpenGL(window, true);
ImGui_ImplOpenGL3_Init("#version 330");
```

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## 3. Start a New ImGui Frame in Your Render Loop

At the beginning of each frame:

```cpp
ImGui_ImplOpenGL3_NewFrame();
ImGui_ImplGlfw_NewFrame();
ImGui::NewFrame();
```

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## 4. Show the FPS Overlay

Add this code in your render loop to display the FPS in the top right corner:

```cpp
ImGui::SetNextWindowPos(ImVec2(W_width - 110, 10), ImGuiCond_Always);
ImGui::SetNextWindowBgAlpha(0.35f); // Transparent background
ImGui::Begin("FPS", nullptr, ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_AlwaysAutoResize |
                           ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoSavedSettings |
                           ImGuiWindowFlags_NoFocusOnAppearing | ImGuiWindowFlags_NoNav);
ImGui::Text("FPS: %.1f", ImGui::GetIO().Framerate);
ImGui::End();
```

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## 5. Render ImGui

After your normal OpenGL rendering:

```cpp
ImGui::Render();
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
```

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## 6. Cleanup ImGui on Exit

Before exiting your application:

```cpp
ImGui_ImplOpenGL3_Shutdown();
ImGui_ImplGlfw_Shutdown();
ImGui::DestroyContext();
```

---

## Notes

- Make sure to link against ImGui and its backends in your build system.
- You may need to adjust the window position (`W_width - 110`) depending on your window size variable.
- For more details, see the [ImGui examples](https://github.com/ocornut/imgui/tree/master/examples).