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-----------------------------------------------------------------------
dear imgui, v1.80 WIP
Backends
-----------------------------------------------------------------------
(See docs/ and examples/ for more documentation)
-----------------------------------------------------------------------
This folder contains backends for popular platforms/graphics API, which you can use in
your application or engine to easily integrate Dear ImGui.
- The 'Platform' backends are in charge of: mouse/keyboard/gamepad inputs, cursor shape, timing, windowing.
e.g. Windows (imgui_impl_win32.cpp), GLFW (imgui_impl_glfw.cpp), SDL2 (imgui_impl_sdl.cpp), etc.
- The 'Renderer' backends are in charge of: creating atlas texture, rendering imgui draw data.
e.g. DirectX11 (imgui_impl_dx11.cpp), OpenGL/WebGL (imgui_impl_opengl3.cpp), Vulkan (imgui_impl_vulkan.cpp), etc.
- For some high-level frameworks, a single backend usually handle both 'Platform' and 'Renderer' parts.
e.g. Allegro 5 (imgui_impl_allegro5.cpp), Marmalade (imgui_impl_marmalade5.cpp).
An application usually combines 1 Platform backend + 1 Renderer backend + main ImGui sources.
For example, the example_win32_directx11/ application combines imgui_impl_win32.cpp + imgui_impl_dx11.cpp.
See examples/README.txt for details.
---------------------------------------
WHAT ARE BACKENDS?
---------------------------------------
Dear ImGui is highly portable and only requires a few things to run and render, typically:
- Required: providing mouse/keyboard inputs.
- Required: uploading the font atlas texture into graphics memory.
- Required: rendering indexed textured triangles with a clipping rectangle.
Extra features are opt-in, our backends try to support as many as possible:
- Optional: custom texture binding support.
- Optional: clipboard support.
- Optional: gamepad support.
- Optional: mouse cursor shape support.
- Optional: IME support.
- Optional: multi-viewports support.
etc.
This is essentially what the backends in this folder are providing + obligatory portability cruft.
It is important to understand the difference between the core Dear ImGui library (files in the root folder)
and backends which we are describing here (backends/ folder).
- Some issues may only be backend or platform specific.
- You should be able to write backends for pretty much any platform and any 3D graphics API.
e.g. get creative and have your backend perform rendering remotely, on a different machine
than the one running Dear ImGui, etc.
-----------------------------------------------------------------------
USING A CUSTOM ENGINE?
-----------------------------------------------------------------------
You will likely be tempted to start by rewrite your own backend using your own custom/high-level facilities...
Think twice!
If you are new to Dear ImGui, first try using the existing backends as-is.
You will save lots of time integrating the library.
You can LATER decide to rewrite yourself a custom backend if you really need to.
In most situations, custom backends have less features and more bugs than the standard backends we provide.
If you want portability, you can use multiple backends and choose between them either at compile time
or at runtime.
Example A: your engine is built over Windows + DirectX11 but you have your own high-level rendering
system layered over DirectX11.
- Suggestion: try using imgui_impl_win32.cpp + imgui_impl_dx11.cpp first.
Once it works, if you really need it you can replace the imgui_impl_dx11.cpp code with a
custom renderer using your own rendering functions, and keep using the standard Win32 code etc.
Example B: your engine runs on Windows, Mac, Linux and uses DirectX11, Metal, Vulkan respectively.
- Suggestion: use multiple generic backends!
Once it works, if you really need it you can replace parts of backends with your own abstractions.
Example C: your engine runs on platforms we can't provide public backends for (e.g. PS4/PS5, Switch),
and you have high-level systems everywhere.
- Suggestion: try using a non-portable backend first (e.g. win32 + underlying graphics API) to get
your desktop builds working first. This will get you running faster and get your acquainted with
how Dear ImGui works and is setup. You can then rewrite a custom backend using your own engine API.
Also:
The multi-viewports feature of the 'docking' branch allows Dear ImGui windows to be seamlessly detached
from the main application window. This is achieved using an extra layer to the Platform and Renderer
backends, which allows Dear ImGui to communicate platform-specific requests.
Supporting the multi-viewports feature correctly using 100% of your own abstractions is more difficult
than supporting single-viewport.
If you decide to use unmodified imgui_impl_xxxx.cpp files, you can automatically benefit from
improvements and fixes related to viewports and platform windows without extra work on your side.
---------------------------------------
LIST OF BACKENDS
---------------------------------------
List of Platforms Backends in this repository:
imgui_impl_glfw.cpp ; GLFW (Windows, macOS, Linux, etc.) http://www.glfw.org/
imgui_impl_osx.mm ; macOS native API (not as feature complete as glfw/sdl backends)
imgui_impl_sdl.cpp ; SDL2 (Windows, macOS, Linux, iOS, Android) https://www.libsdl.org
imgui_impl_win32.cpp ; Win32 native API (Windows)
imgui_impl_glut.cpp ; GLUT/FreeGLUT (absolutely not recommended in 2020!)
List of Renderer Backends in this repository:
imgui_impl_dx9.cpp ; DirectX9
imgui_impl_dx10.cpp ; DirectX10
imgui_impl_dx11.cpp ; DirectX11
imgui_impl_dx12.cpp ; DirectX12
imgui_impl_metal.mm ; Metal (with ObjC)
imgui_impl_opengl2.cpp ; OpenGL 2 (legacy, fixed pipeline <- don't use with modern OpenGL context)
imgui_impl_opengl3.cpp ; OpenGL 3/4, OpenGL ES 2, OpenGL ES 3 (modern programmable pipeline)
imgui_impl_vulkan.cpp ; Vulkan
Emscripten is also supported.
The example_emscripten/ app uses imgui_impl_sdl.cpp + imgui_impl_opengl3.cpp, but other combos are possible.
List of high-level Frameworks Backends in this repository: (combine Platform + Renderer)
imgui_impl_allegro5.cpp
imgui_impl_marmalade.cpp
Backends for third-party frameworks, graphics API or other programming languages:
https://github.com/ocornut/imgui/wiki/Bindings
(AGS/Adventure Game Studio, Amethyst, bsf, Cinder, Cocos2d-x, Diligent Engine, Flexium,
GML/Game Maker Studio2, GTK3+OpenGL3, Irrlicht Engine, LÖVE+LUA, Magnum, NanoRT, Nim Game Lib,
Ogre, openFrameworks, OSG/OpenSceneGraph, Orx, px_render, Qt/QtDirect3D, SFML, Sokol,
Unreal Engine 4, vtk, Win32 GDI, etc.)
---------------------------------------
RECOMMENDED BACKENDS
---------------------------------------
Recommended platform/frameworks for portable applications:
Library: GLFW
Webpage: https://github.com/glfw/glfw
Backend: imgui_impl_glfw.cpp
Library: SDL2
Webpage: https://www.libsdl.org
Backend: imgui_impl_sdl.cpp
Library: Sokol (lower-level than GLFW/SDL)
Webpage: https://github.com/floooh/sokol
Backend: Use util/sokol_imgui.h in Sokol repository.

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-----------------------------------------------------------------------
dear imgui, v1.80 WIP
Examples applications
-----------------------------------------------------------------------
(See docs/ and backends/ for more documentation)
-----------------------------------------------------------------------
This folder contains example applications (standalone, ready-to-build) for variety of
platforms and graphics APIs. They all use standard backends from the backends/ folder.
You can find Windows binaries for some of those example applications at:
http://www.dearimgui.org/binaries
---------------------------------------
GETTING STARTED
---------------------------------------
Integration in a typical existing application, should take <20 lines when using standard backends.
At initialization:
call ImGui::CreateContext()
call ImGui_ImplXXXX_Init() for each backend.
At the beginning of your frame:
call ImGui_ImplXXXX_NewFrame() for each backend.
call ImGui::NewFrame()
At the end of your frame:
call ImGui::Render()
call ImGui_ImplXXXX_RenderDrawData() for your Renderer backend.
At shutdown:
call ImGui_ImplXXXX_Shutdown() for each backend.
call ImGui::DestroyContext()
Example (using backends/imgui_impl_win32.cpp + backends/imgui_impl_dx11.cpp):
// Create a Dear ImGui context, setup some options
ImGui::CreateContext();
ImGuiIO& io = ImGui::GetIO();
io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable some options
// Initialize Platform + Renderer backends (here: using imgui_impl_win32.cpp + imgui_impl_dx11.cpp)
ImGui_ImplWin32_Init(my_hwnd);
ImGui_ImplDX11_Init(my_d3d_device, my_d3d_device_context);
// Application main loop
while (true)
{
// Beginning of frame: update Renderer + Platform backend, start Dear ImGui frame
ImGui_ImplDX11_NewFrame();
ImGui_ImplWin32_NewFrame();
ImGui::NewFrame();
// Any application code here
ImGui::Text("Hello, world!");
// End of frame: render Dear ImGui
ImGui::Render();
ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
// Swap
g_pSwapChain->Present(1, 0);
}
// Shutdown
ImGui_ImplDX11_Shutdown();
ImGui_ImplWin32_Shutdown();
ImGui::DestroyContext();
Please read 'PROGRAMMER GUIDE' in imgui.cpp for notes on how to setup Dear ImGui in your codebase.
Please read the comments and instruction at the top of each file.
Please read FAQ at http://www.dearimgui.org/faq
If you are using of the backend provided here, you can add the backends/imgui_impl_xxxx(.cpp,.h)
files to your project and use as-in. Each imgui_impl_xxxx.cpp file comes with its own individual
Changelog, so if you want to update them later it will be easier to catch up with what changed.
---------------------------------------
EXAMPLE APPLICATIONS
---------------------------------------
example_allegro5/
Allegro 5 example.
= main.cpp + imgui_impl_allegro5.cpp
example_apple_metal/
OSX & iOS + Metal.
= main.m + imgui_impl_osx.mm + imgui_impl_metal.mm
It is based on the "cross-platform" game template provided with Xcode as of Xcode 9.
(NB: imgui_impl_osx.mm is currently not as feature complete as other platforms backends.
You may prefer to use the GLFW Or SDL backends, which will also support Windows and Linux.)
example_apple_opengl2/
OSX + OpenGL2.
= main.mm + imgui_impl_osx.mm + imgui_impl_opengl2.cpp
(NB: imgui_impl_osx.mm is currently not as feature complete as other platforms backends.
You may prefer to use the GLFW Or SDL backends, which will also support Windows and Linux.)
example_empscripten:
Emcripten + SDL2 + OpenGL3+/ES2/ES3 example.
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_opengl3.cpp
Note that other examples based on SDL or GLFW + OpenGL could easily be modified to work with Emscripten.
We provide this to make the Emscripten differences obvious, and have them not pollute all other examples.
example_glfw_metal/
GLFW (Mac) + Metal example.
= main.mm + imgui_impl_glfw.cpp + imgui_impl_metal.mm
example_glfw_opengl2/
GLFW + OpenGL2 example (legacy, fixed pipeline).
= main.cpp + imgui_impl_glfw.cpp + imgui_impl_opengl2.cpp
**DO NOT USE OPENGL2 CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
**Prefer using OPENGL3 code (with gl3w/glew/glad/glad2/glbinding, you can replace the OpenGL function loader)**
This code is mostly provided as a reference to learn about Dear ImGui integration, because it is shorter.
If your code is using GL3+ context or any semi modern OpenGL calls, using this renderer is likely to
make things more complicated, will require your code to reset many OpenGL attributes to their initial
state, and might confuse your GPU driver. One star, not recommended.
example_glfw_opengl3/
GLFW (Win32, Mac, Linux) + OpenGL3+/ES2/ES3 example (programmable pipeline).
= main.cpp + imgui_impl_glfw.cpp + imgui_impl_opengl3.cpp
This uses more modern OpenGL calls and custom shaders.
Prefer using that if you are using modern OpenGL in your application (anything with shaders).
(Please be mindful that accessing OpenGL3+ functions requires a function loader, which are a frequent
source for confusion for new users. We use a loader in imgui_impl_opengl3.cpp which may be different
from the one your app normally use. Read imgui_impl_opengl3.h for details and how to change it.)
example_glfw_vulkan/
GLFW (Win32, Mac, Linux) + Vulkan example.
= main.cpp + imgui_impl_glfw.cpp + imgui_impl_vulkan.cpp
This is quite long and tedious, because: Vulkan.
For this example, the main.cpp file exceptionally use helpers function from imgui_impl_vulkan.h/cpp.
example_glut_opengl2/
GLUT (e.g., FreeGLUT on Linux/Windows, GLUT framework on OSX) + OpenGL2.
= main.cpp + imgui_impl_glut.cpp + imgui_impl_opengl2.cpp
Note that GLUT/FreeGLUT is largely obsolete software, prefer using GLFW or SDL.
example_marmalade/
Marmalade example using IwGx.
= main.cpp + imgui_impl_marmalade.cpp
example_null
Null example, compile and link imgui, create context, run headless with no inputs and no graphics output.
= main.cpp
This is used to quickly test compilation of core imgui files in as many setups as possible.
Because this application doesn't create a window nor a graphic context, there's no graphics output.
example_sdl_directx11/
SDL2 + DirectX11 example, Windows only.
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_dx11.cpp
This to demonstrate usage of DirectX with SDL.
example_sdl_metal/
SDL2 (Mac) + Metal example.
= main.mm + imgui_impl_sdl.cpp + imgui_impl_metal.mm
example_sdl_opengl2/
SDL2 (Win32, Mac, Linux etc.) + OpenGL example (legacy, fixed pipeline).
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_opengl2.cpp
**DO NOT USE OPENGL2 CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
**Prefer using OPENGL3 code (with gl3w/glew/glad/glad2/glbinding, you can replace the OpenGL function loader)**
This code is mostly provided as a reference to learn about Dear ImGui integration, because it is shorter.
If your code is using GL3+ context or any semi modern OpenGL calls, using this renderer is likely to
make things more complicated, will require your code to reset many OpenGL attributes to their initial
state, and might confuse your GPU driver. One star, not recommended.
example_sdl_opengl3/
SDL2 (Win32, Mac, Linux, etc.) + OpenGL3+/ES2/ES3 example.
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_opengl3.cpp
This uses more modern OpenGL calls and custom shaders.
Prefer using that if you are using modern OpenGL in your application (anything with shaders).
(Please be mindful that accessing OpenGL3+ functions requires a function loader, which are a frequent
source for confusion for new users. We use a loader in imgui_impl_opengl3.cpp which may be different
from the one your app normally use. Read imgui_impl_opengl3.h for details and how to change it.)
example_sdl_vulkan/
SDL2 (Win32, Mac, Linux, etc.) + Vulkan example.
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_vulkan.cpp
This is quite long and tedious, because: Vulkan.
For this example, the main.cpp file exceptionally use helpers function from imgui_impl_vulkan.h/cpp.
example_win32_directx9/
DirectX9 example, Windows only.
= main.cpp + imgui_impl_win32.cpp + imgui_impl_dx9.cpp
example_win32_directx10/
DirectX10 example, Windows only.
= main.cpp + imgui_impl_win32.cpp + imgui_impl_dx10.cpp
example_win32_directx11/
DirectX11 example, Windows only.
= main.cpp + imgui_impl_win32.cpp + imgui_impl_dx11.cpp
example_win32_directx12/
DirectX12 example, Windows only.
= main.cpp + imgui_impl_win32.cpp + imgui_impl_dx12.cpp
This is quite long and tedious, because: DirectX12.
---------------------------------------
MISCELLANEOUS
---------------------------------------
Building:
Unfortunately in 2020 it is still tedious to create and maintain portable build files using external
libraries (the kind we're using here to create a window and render 3D triangles) without relying on
third party software. For most examples here we choose to provide:
- Makefiles for Linux/OSX
- Batch files for Visual Studio 2008+
- A .sln project file for Visual Studio 2012+
- Xcode project files for the Apple examples
Please let us know if they don't work with your setup!
You can probably just import the imgui_impl_xxx.cpp/.h files into your own codebase or compile those
directly with a command-line compiler.
If you are interested in using Cmake to build and links examples, see:
https://github.com/ocornut/imgui/pull/1713 and https://github.com/ocornut/imgui/pull/3027
Things feeling laggy?
Dear ImGui has no particular extra lag for most behaviors,
e.g. the value of 'io.MousePos' provided at the time of NewFrame() will result in windows being moved
to the right spot at the time of EndFrame()/Render(). At 60 FPS your experience should be pleasant.
However, consider that OS mouse cursors are typically drawn through a very specific hardware accelerated
path and will feel smoother than the majority of contents rendered via regular graphics API (including,
but not limited to Dear ImGui windows). Because UI rendering and interaction happens on the same plane
as the mouse, that disconnect may be jarring to particularly sensitive users.
You may experiment with enabling the io.MouseDrawCursor flag to request Dear ImGui to draw a mouse cursor
using the regular graphics API, to help you visualize the difference between a "hardware" cursor and a
regularly rendered software cursor.
However, rendering a mouse cursor at 60 FPS will feel sluggish so you likely won't want to enable that at
all times. It might be beneficial for the user experience to switch to a software rendered cursor _only_
when an interactive drag is in progress.
Note that some setup or GPU drivers are likely to be causing extra display lag depending on their settings.
If you feel that dragging windows feels laggy and you are not sure what the cause is: try to build a simple
drawing a flat 2D shape directly under the mouse cursor!