This is a header-only library and sample code for using Filament with GLFW and ImGui.

Building and Running

git clone https://github.com/google/filament.git && \
  (cd filament && git checkout tags/v1.32.4)
git clone https://github.com/glfw/glfw.git && \
  (cd glfw && git checkout tags/3.3.8)
git clone https://github.com/ambrusc/filament-glfw-imgui.git && \
  cd filament-glfw-imgui && \
  ./build.sh deps && \
  ./build.sh resources && \
  ./build.sh demo && \
    (cd build && ./demo)

Tested Platforms

• MacOS, x86-64, Filament backend Metal
• Linux: Manjaro, x86-64, Filament backend OpenGL and Vulkan, X11

NOTE: I think this code should build with MSYS2/mingw64 on Windows, but I haven't tested yet.

Principles

The code strives to be concise and readable (reading the code, including build.sh is encouraged).

Everything in filament_glfw_imgui strives to be as modular as possible. It's header-only, and use should be able to pick and choose which parts work well in your app. In addition, we try to expose a fairly granular set of APIs. If the easy-mode "App" doesn't work for you, you can of course modify it, or just use its consituent components any way you'd like.

Folder Structure

• 3p: "third party" stuff
• build: the output folder for builds
• filament_native: thin platform-specific library to help initialze the native window for Filament
• filament_glfw_imgui: main header-only library for this repo
• demo: a working sample app (take the fs_* files with a grain of salt; they probably don't follow Filament best practices.)

Rationale

• Why make this library, and not just use FilamentApp, etc?
  • They're not intended for production use, and not considered part of the supported library.
    • #6154 "These are not libraries we wish to support as public APIs. Maybe filagui but definitely not filament app. At least not in its current form."
• Why not SDL like the filament samples?
  • I couldn't get it to run on Linux without horrendous screen tearing that would appear after a few minutes of seemingly vsync'd rendering. It seemed to be platform-specific, and would cause Plasma desktop to flicker, corrupting windows of other apps. It was probably user error on my part, but I eventually gave up.
  • #5242 I'm not the only one with issues on linux.
  • GLFW also claims to be lighter weight than SDL and I've had good luck with it in the past.
• But [such-and-such] already did this. Why not use theirs?
  • Here are some alternatives I found, which may be useful to you. If you know of any more, I'm open to linking those as well.
• Because it was a challenge and I felt like doing it :-)

Known (or Suspected) Issues

• Vsync is not well supported in Filament
  • But if Vsync is enabled, Filament seems to let you know when a frame is already rendered (or currently rendering) for the next screen refresh.
  • The app/code doesn't seem to have access to enabling or disabling vsync - it can be toggled in your video driver though.
  • #6675: "The sample schedules frames badly using a fixed timestep of ~16ms, it doesn't try to use vsync at all."
  • #4337: You can force Vsync on/off in your video driver.
  • #636: Claims that Vsync callbacks were added but newer issues (above) seem to indicate otherwise.
• Few platforms tested: see Tested Platforms above
• I haven't tested Wayland and it probably would require a new implementation of filament_native_...cpp.
• filament_imgui only supports 65535 vertices total. This is fixable, I just haven't done it yet.

Alternatives

• prideout/glfw_filament.cpp
• roxlu/filament-with-glfw