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ImGui-SFML

Library which allows you to use Dear ImGui with SFML

screenshot

Based on this repository with big improvements and changes.

State of Development

Dependencies

Contributing

How-to

Building and integrating into your CMake project

It's highly recommended to use FetchContent or git submodules to get SFML and Dear ImGui into your build.

See this file - if you do something similar, you can then just link to ImGui-SFML as simply as:

target_link_libraries(game
  PUBLIC
    ImGui-SFML::ImGui-SFML
)

Integrating into your project manually

Other ways to add to your project

Not recommended, as they're not maintained officially. Tend to lag behind and stay on older versions.

Using ImGui-SFML in your code

If you only draw ImGui widgets without any SFML stuff, then you'll might need to call window.resetGLStates() before rendering anything. You only need to do it once.

Example code

See example file here

#include "imgui.h"
#include "imgui-SFML.h"

#include <SFML/Graphics/CircleShape.hpp>
#include <SFML/Graphics/RenderWindow.hpp>
#include <SFML/System/Clock.hpp>
#include <SFML/Window/Event.hpp>

int main() {
    sf::RenderWindow window(sf::VideoMode({640, 480}), "ImGui + SFML = <3");
    window.setFramerateLimit(60);
    ImGui::SFML::Init(window);

    sf::CircleShape shape(100.f);
    shape.setFillColor(sf::Color::Green);

    sf::Clock deltaClock;
    while (window.isOpen()) {
        while (const auto event = window.pollEvent()) {
            ImGui::SFML::ProcessEvent(window, *event);

            if (event->is<sf::Event::Closed>()) {
                window.close();
            }
        }

        ImGui::SFML::Update(window, deltaClock.restart());

        ImGui::ShowDemoWindow();

        ImGui::Begin("Hello, world!");
        ImGui::Button("Look at this pretty button");
        ImGui::End();

        window.clear();
        window.draw(shape);
        ImGui::SFML::Render(window);
        window.display();
    }

    ImGui::SFML::Shutdown();
}

Fonts how-to

Default font is loaded if you don't pass false in ImGui::SFML::Init. Call ImGui::SFML::Init(window, false); if you don't want default font to be loaded.

IO.Fonts->Clear(); // clear fonts if you loaded some before (even if only default one was loaded)
// IO.Fonts->AddFontDefault(); // this will load default font as well
IO.Fonts->AddFontFromFileTTF("font1.ttf", 8.f);
IO.Fonts->AddFontFromFileTTF("font2.ttf", 12.f);

ImGui::SFML::UpdateFontTexture(); // important call: updates font texture

ImGui::PushFont(ImGui::GetIO().Fonts->Fonts[0]);
ImGui::Button("Look at this pretty button");
ImGui::PopFont();

ImGui::PushFont(ImGui::GetIO().Fonts->Fonts[1]);
ImGui::TextUnformatted("IT WORKS!");
ImGui::PopFont();

The first loaded font is treated as the default one and doesn't need to be pushed with ImGui::PushFont.

Multiple windows

See examples/multiple_windows to see how you can create multiple SFML and run different ImGui contexts in them.

SFML related ImGui overloads / new widgets

There are some useful overloads implemented for SFML objects (see imgui-SFML.h for other overloads):

ImGui::Image(const sf::Sprite& sprite);
ImGui::Image(const sf::Texture& texture);
ImGui::Image(const sf::RenderTexture& texture);

ImGui::ImageButton(const sf::Sprite& sprite);
ImGui::ImageButton(const sf::Texture& texture);
ImGui::ImageButton(const sf::RenderTexture& texture);

A note about sf::RenderTexture

sf::RenderTexture's texture is stored with pixels flipped upside down. To display it properly when drawing ImGui::Image or ImGui::ImageButton, use overloads for sf::RenderTexture:

sf::RenderTexture texture;
sf::Sprite sprite(texture.getTexture());
ImGui::Image(texture);              // OK
ImGui::Image(sprite);               // NOT OK
ImGui::Image(texture.getTexture()); // NOT OK

If you want to draw only a part of sf::RenderTexture and you're trying to use sf::Sprite the texture will be displayed upside-down. To prevent this, you can do this:

// make a normal sf::Texture from sf::RenderTexture's flipped texture
sf::Texture texture(renderTexture.getTexture());

sf::Sprite sprite(texture);
ImGui::Image(sprite); // the texture is displayed properly

For more notes see this issue.

Mouse cursors

You can change your cursors in ImGui like this:

ImGui::SetMouseCursor(ImGuiMouseCursor_TextInput);

By default, your system cursor will change and will be rendered by your system. If you want SFML to draw your cursor with default ImGui cursors (the system cursor will be hidden), do this:

ImGuiIO& io = ImGui::GetIO();
io.MouseDrawCursor = true;

Keyboard/Gamepad navigation

Starting with ImGui 1.60, there's a feature to control ImGui with keyboard and gamepad. To use keyboard navigation, you just need to do this:

ImGuiIO& io = ImGui::GetIO();
io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;

Gamepad navigation requires more work, unless you have XInput gamepad, in which case the mapping is automatically set for you. But you can still set it up for your own gamepad easily, just take a look how it's done for the default mapping here. And then you need to do this:

ImGuiIO& io = ImGui::GetIO();
io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;

By default, the first active joystick is used for navigation, but you can set joystick id explicitly like this:

ImGui::SFML::SetActiveJoystickId(5);

High DPI screens

As SFML is not currently DPI aware, your GUI may show at the incorrect scale. This is particularly noticeable on systems with "Retina" / "4K" / "UHD" displays.

To work around this on macOS, you can create an app bundle (as opposed to just the exe) then modify the info.plist so that "High Resolution Capable" is set to "NO".

Another option to help ameliorate this, at least for getting started and for the common ImGui use-case of "developer/debug/building UI", is to explore FontGlobalScale:

ImGuiIO& io = ImGui::GetIO();
io.FontGlobalScale = 2.0; // or any other value hardcoded or loaded from your config logic

License

This library is licensed under the MIT License, see LICENSE for more information.