Filament

Filament is a real-time physically based rendering engine for Android, Linux, macOS and Windows. This rendering engine was designed to be as small as possible and as efficient as possible on Android.

Filament is currently used in the Sceneform library both at runtime on Android devices and as the renderer inside the Android Studio plugin.

Documentation

• Filament, an in-depth explanation of real-time physically based rendering, the graphics capabilities and implementation of Filament. This document explains the math and reasoning behind most of our decisions. This document is a good introduction to PBR for graphics programmers.
• Materials, the full reference documentation for our material system. This document explains our different material models, how to use the material compiler matc and how to write custom materials.
• Material Properties, a reference sheet for the standard material model.

Samples

Here are a few sample materials rendered with Filament:

Features

APIs

• Native C++ API for Android, Linux, macOS and Windows
• Java/JNI API for Android, Linux, macOS and Windows
• Python bindings

Backends

• OpenGL 4.1+ for Linux, macOS and Windows
• OpenGL ES 3.0+ for Android
• Vulkan 1.0 for Android, Linux, macOS (with MoltenVk) and Windows

Rendering

• Clustered forward renderer
• Cook-Torrance microfacet specular BRDF
• Lambertian diffuse BRDF
• HDR/linear lighting
• Metallic workflow
• Clear coat
• Anisotropic lighting
• Approximated translucent (subsurface) materials (direct and indirect lighting)
• Cloth shading
• Normal mapping & ambient occlusion mapping
• Image-based lighting
• Physically-based camera (shutter speed, sensitivity and aperture)
• Physical light units
• Point light, spot light and directional light
• ACES-like tone-mapping
• Temporal dithering
• FXAA or MSAA
• Dynamic resolution (on Android)

Future

Many other features have been either prototyped or planned:

• IES light profiles
• Area lights
• Fog
• Color grading
• Bloom
• TAA
• etc.

Directory structure

• filament: Filament engine and its supporting libraries and tools
  • android: Android libraries and projects
  • art: Source for various artworks (logos, PDF manuals, etc.)
  • assets: 3D assets to use with sample applications
  • build: CMake build scripts
  • docs: Documentation
    • math: Mathematica notebooks used to explore BRDFs, equations, etc.
  • filament: Filament engine
  • ide: Configuration files for IDEs (CLion, etc.)
  • java: Java bindings for Filament libraries
  • libs: Libraries
    • bluegl: OpenGL bindings for macOS, Linux and Windows
    • bluevk: Vulkan bindings for macOS, Linux, Windows and Android
    • filabridge: Library shared by the Filament engine and host tools
    • filaflat: Serialization/deserialization library used for materials
    • filagui: Helper library for Dear ImGui
    • filamat: Material generation library
    • image: Image filtering and simple transforms
    • imageio: Image file reading / writing, only intended for internal use
    • math: Math library
    • utils: Utility library (threads, memory, data structures, etc.)
  • samples: Sample desktop applications
  • shaders: Shaders used by filamat and matc
  • third_party: External libraries and assets
  • tools: Host tools
    • cmgen: Image-based lighting asset generator
    • filamesh: Mesh converter
    • matc: Material compiler
    • matinfo Displays information about materials compiled with matc
    • normal-blending: Tool to blend normal maps
    • roughness-prefilter: Pre-filters a roughness map from a normal map to reduce aliasing
    • skygen: Physically-based sky environment texture generator
    • specular-color: Computes the specular color of conductors based on spectral data

Building Filament

Prerequisites

To build Filament, you must first install the following tools:

• CMake 3.4 (or more recent)
• clang 5.0 (or more recent)
• ninja 1.8 (or more recent)

To build the Java based components of the project you can optionally install (recommended):

• OpenJDK 1.8 (or more recent)

Additional dependencies may be required for your operating system. Please refer to the appropriate section below.

To build Filament for Android you must also install the following:

• Android Studio 3.1
• Android SDK
• Android NDK

Environment variables

Make sure the environment variable ANDROID_HOME points to the location of your Android SDK.

By default our build system will attempt to compile the Java bindings. To do so, the environment variable JAVA_HOME should point to the location of your JDK.

IDE

We recommend using CLion to develop for Filament. Simply open the root directory's CMakeList.txt in CLion to obtain a usable project.

Easy build

Once the required OS specific dependencies listed below are installed, you can use the script located in build.sh to build Filament easily on macOS and Linux.

This script can be invoked from anywhere and will produce build artifacts in the out/ directory inside the Filament source tree.

To trigger an incremental debug build:

$ ./build.sh debug

To trigger an incremental release build:

$ ./build.sh release

To trigger both incremental debug and release builds:

$ ./build.sh debug release

To install the libraries and executables in out/debug/ and out/release/, add the -i flag. You can force a clean build by adding the -c flag. The script offers more features described by executing build.sh -h.

Disabling Java builds

By default our build system will attempt to compile the Java bindings. If you wish to skip this compilation step simply pass the -j flag to build.sh:

$ ./build.sh -j release

If you use CMake directly instead of the build script, pass -DENABLE_JAVA=OFF to CMake instead.

Linux

Make sure you've installed the following dependencies:

• libglu1-mesa-dev
• libc++-dev (libcxx-devel on Fedora)
• libc++abi-dev
• ninja-build

In addition your distribution might require:

• libxi-dev

Then invoke cmake:

$ mkdir out/cmake-release
$ cd out/cmake-release
$ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../release/filament ../..

If you experience link errors you must ensure that you are using libc++abi by passing this extra parameter to cmake:

-DFILAMENT_REQUIRES_CXXABI=true

Your Linux distribution might default to gcc instead of clang, if that's the case invoke cmake with the following command:

$ mkdir out/cmake-release
$ cd out/cmake-release
# Or use a specific version of clang, for instance /usr/bin/clang-5.0
$ CC=/usr/bin/clang CXX=/usr/bin/clang++ \
    cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../release/filament ../..

You can also export the CC and CXX environment variables to always point to clang. Another solution is to use update-alternatives to both change the default compiler, and point to a specific version of clang:

$ update-alternatives --install /usr/bin/cc cc /usr/bin/clang 100
$ update-alternatives --install /usr/bin/c++ c++ /usr/bin/clang++ 100
$ update-alternatives --install /usr/bin/clang clang /usr/bin/clang-5.0 100
$ update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-5.0 100

Finally, invoke ninja:

$ ninja

This will build Filament, its tests and samples, and various host tools.

macOS

To compile Filament you must have the most recent version of Xcode installed and you need to make sure the command line tools are setup by running:

$ xcode-select --install

After installing Java 1.8 you must also ensure that your JAVA_HOME environment variable is properly set. If it doesn't already point to the appropriate JDK, you can simply add the following to your .profile:

export JAVA_HOME="$(/usr/libexec/java_home)"

Then run cmake and ninja to trigger a build:

$ mkdir out/cmake-release
$ cd out/cmake-release
$ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../release/filament ../..
$ ninja

Windows

The following instructions have been tested on a machine running Windows 10. They should take you from a machine with only the operating system to a machine able to build and run Filament.

Google employees require additional steps which can be found here go/filawin.

Install the following components:

• Windows 10 SDK
• Visual Studio 2015
• Clang 6
• Python 3.7
• Git 2.16.1 or later
• Cmake 3.11 or later

Open an VS2015 x64 Native Tools terminal (click the start button, type "x64 native tools" and select: "VS2015 x64 Native Tools Command Prompt").

Create a working directory:

> mkdir out/cmake-release
> cd out/cmake-release

Create the msBuild project:

> cmake -T"LLVM-vs2014" -G "Visual Studio 14 2015 Win64" ../..

Check out the output and make sure Clang for Windows frontend was found. You should see a line showing the following ouput.

Clang:C:/Program Files/LLVM/msbuild-bin/cl.exe

You are now ready to build:

> msbuild  TNT.sln /t:material_sandbox /m /p:configuration=Debug

Run it:

> samples\material_sandbox.exe ..\..\assets\models\monkey\monkey.obj

Tips

• To troubleshoot an issue, use verbose mode via /v:d flag.
• To build a specific project, use /t:NAME flag (e.g: /t:material_sandbox).
• To build using more than one core, use parallel build flag: /m.
• To build a specific profile, used /p:configuration= (e.g: /p:configuration=Debug, /p:configuration=Release, and /p:configuration=RelWithDebInfo).
• The msBuild project is what is used by Visual Studio behind the scene to build. Building from VS or from the command-line is the same thing.

Building with Ninja on Windows

Alternatively, you can use Ninja to build for Windows. An MSVC installation is still necessary.

First, install the dependencies listed under Windows as well as Ninja. Then open up a VS2015 x64 Native Tools terminal as before. Create a build directory inside Filament and run the following CMake command:

cmake .. -G Ninja ^
-DCMAKE_CXX_COMPILER:PATH="C:\Program Files\LLVM\bin\clang-cl.exe" ^
-DCMAKE_C_COMPILER:PATH="C:\Program Files\LLVM\bin\clang-cl.exe" ^
-DCMAKE_LINKER:PATH="C:\Program Files\LLVM\bin\lld-link.exe" ^
-DCMAKE_BUILD_TYPE=Release

You should then be able to build by invoking Ninja:

ninja

Development tips

• Before shipping a binary, make sure you used Release profile and make sure you have no libc/libc++ dependencies with Dependency Walker.
• Application Verifier and gflags.exe can be of great help to trackdown heap corruption. Application Verifier is easy to setup with a GUI. For gflags, use: gflags /p /enable pheap-buggy.exe.

Running a simple test

To confirm Filament was properly built, run the following command from the build directory:

./samples/material_sandbox --ibl=../../samples/envs/office ../../assets/models/sphere/sphere.obj

Android

Before building Filament for Android, make sure to build Filament for your host. Some of the host tools are required to successfully build for Android.

Filament can be built for the following architectures:

• ARM 64-bit (arm64-v8a)
• ARM 32-bit (armeabi-v7a)
• Intel 64-bit (x86_64)
• Intel 32-bit (x86)

Note that the main target is the ARM 64-bit target. Our implementation is optimized first and foremost for arm64-v8a.

Easy build

The easiest way to build Filament for Android is to use build.sh and the -p android flag. For instance to build the release target:

$ ./build.sh -p android release

Run build.sh -h for more information.

ARM 64-bit target (arm64-v8a)

Linux toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch arm64 --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Linux/aarch64-linux-android-4.9

Darwin toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch arm64 --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Darwin/aarch64-linux-android-4.9

Compiling

Then invoke CMake in a build directory of your choice, inside of filament's directory:

$ mkdir out/android-build-release-aarch64
$ cd out/android-build-release-aarch64
$ cmake -G Ninja -DCMAKE_TOOLCHAIN_FILE=../../build/toolchain-aarch64-linux-android.cmake \
        -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../android-release/filament ../..

And then invoke ninja:

$ ninja install

or

$ ninja install/strip

This will generate Filament's Android binaries in out/android-release. This location is important to build the Android Studio projects located in filament/android. After install, the library binaries should be found in out/android-release/filament/lib/arm64-v8a.

ARM 32-bit target (armeabi-v7a)

Linux toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch arm --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Linux/arm-linux-androideabi-4.9

Darwin toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch arm --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Darwin/arm-linux-androideabi-4.9

Compiling

Then invoke CMake in a build directory of your choice, inside of filament's directory:

$ mkdir out/android-build-release-arm
$ cd out/android-build-release-arm
$ cmake -G Ninja -DCMAKE_TOOLCHAIN_FILE=../../build/toolchain-arm7-linux-android.cmake \
        -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../android-release/filament ../..

And then invoke ninja:

$ ninja install

or

$ ninja install/strip

This will generate Filament's Android binaries in out/android-release. This location is important to build the Android Studio projects located in filament/android. After install, the library binaries should be found in out/android-release/filament/lib/armeabi-v7a.

Intel 64-bit target (x86_64)

Linux toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch x86_64 --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Linux/x86_64-linux-android-4.9

Darwin toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch x86_64 --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Darwin/x86_64-linux-android-4.9

Compiling

Then invoke CMake in a build directory of your choice, sibling of filament's directory:

$ mkdir out/android-build-release-x86_64
$ cd out/android-build-release-x86_64
$ cmake -G Ninja -DCMAKE_TOOLCHAIN_FILE=../../filament/build/toolchain-x86_64-linux-android.cmake \
        -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../out/android-release/filament ../..

And then invoke ninja:

$ ninja install

or

$ ninja install/strip

This will generate Filament's Android binaries in out/android-release. This location is important to build the Android Studio projects located in filament/android. After install, the library binaries should be found in out/android-release/filament/lib/x86_64.

Intel 32-bit target (x86)

Linux toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch x86 --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Linux/i686-linux-android-4.9

Darwin toolchain

$ $SDK/ndk-bundle/build/tools/make_standalone_toolchain.py --arch x86 --api 24 \
        --stl libc++ --force \
        --install-dir toolchains/Darwin/i686-linux-android-4.9

Compiling

Then invoke CMake in a build directory of your choice, sibling of filament's directory:

$ mkdir out/android-build-release-x86
$ cd out/android-build-release-x86
$ cmake -G Ninja -DCMAKE_TOOLCHAIN_FILE=../../filament/build/toolchain-x86-linux-android.cmake \
        -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../out/android-release/filament ../..

And then invoke ninja:

$ ninja install

or

$ ninja install/strip

This will generate Filament's Android binaries in out/android-release. This location is important to build the Android Studio projects located in filament/android. After install, the library binaries should be found in out/android-release/filament/lib/x86.

AAR

Before you attempt to build the AAR, make sure you've compiled and installed the native libraries as explained in the sections above. You must have the following ABIs built in out/android-release/filament/lib/:

• arm64-v8a
• armeabi-v7a
• x86_64
• x86

To build Filament's AAR simply open the Android Studio project in android/filament-android. The AAR is a universal AAR that contains all supported build targets:

• arm64-v8a
• armeabi-v7a
• x86_64
• x86

To filter out unneeded ABIs, rely on the abiFilters of the project that links against Filament's AAR.

Alternatively you can build the AAR from the command line by executing the following the android/filament-android directory:

$ ./gradlew -Pfilament_dist_dir=../../out/android-release/filament assembleRelease

The -Pfilament_dist_dir can be used to specify a different installation directory (it must match the CMake install prefix used in the previous steps).

Using Filament's AAR

Create a new module in your project and select Import .JAR or .AAR Package when prompted. Make sure to add the newly created module as a dependency to your application.

If you do not wish to include all supported ABIs, make sure to create the appropriate flavors in your Gradle build file. For example:

flavorDimensions 'cpuArch'
productFlavors {
    arm8 {
        dimension 'cpuArch'
        ndk {
            abiFilters 'arm64-v8a'
        }
    }
    arm7 {
        dimension 'cpuArch'
        ndk {
            abiFilters 'armeabi-v7a'
        }
    }
    x86_64 {
        dimension 'cpuArch'
        ndk {
            abiFilters 'x86_64'
        }
    }
    x86 {
        dimension 'cpuArch'
        ndk {
            abiFilters 'x86'
        }
    }
    universal {
        dimension 'cpuArch'
    }
}

Running the samples

The samples/ directory contains several examples of how to use Filament with SDL2.

Some of the samples accept FBX/OBJ meshes while others rely on the filamesh file format. To generate a filamesh file from an FBX/OBJ asset, run the filamesh tool (./tools/filamesh/filamesh in your build directory):

filamesh ./assets/models/monkey/monkey.obj monkey.filamesh

Most samples accept an IBL that must be generated using the cmgen tool (./tools/filamesh/cmgen in your build directory). These sample apps expect a path to a directory containing the RGBM files for the IBL. To generate an IBL simply use this command:

cmgen -x ./ibls/ my_ibl.exr 

The source environment map can be a PNG (8 or 16 bit), a PSD (16 or 32 bit), an HDR or an OpenEXR file. The environment map can be an equirectangular projection, a horizontal cross, a vertical cross, or a list of cubemap faces (horizontal or vertical).

cmgen will automatically create a directory based on the name of the source environment map. In the example above, the final directory will be ./ibls/my_ibl/. This directory should contain the pre-filtered environment map (one file per cubemap face and per mip level), the environment map texture for the skybox and a text file containing the spherical harmonics for indirect diffuse lighting.

If you prefer a blurred background, run cmgen with this flag: --extract-blur=0.5. The numerical value is the desired roughness between 0 and 1.

Rendering with Filament

Native Linux, macOS and Windows

You must create an Engine, a Renderer and a SwapChain. The SwapChain is created from a native window pointer (an NSView on macOS or a HDC on Windows for instance):

Engine* engine = Engine::create();
SwapChain* swapChain = engine->createSwapChain(nativeWindow);
Renderer* renderer = engine->createRenderer();

To render a frame you must then create a View, a Scene and a Camera:

Camera* camera = engine->createCamera();
View* view = engine->createView();
Scene* scene = engine->createScene();

view->setCamera(camera);
view->setScene(scene);

Renderables are added to the scene:

Entity renderable = EntityManager::get().create();
// build a quad
RenderableManager::Builder(1)
        .boundingBox({{ -1, -1, -1 }, { 1, 1, 1 }})
        .material(0, materialInstance)
        .geometry(0, RenderableManager::PrimitiveType::TRIANGLES, vertexBuffer, indexBuffer, 0, 6)
        .culling(false)
        .build(*engine, renderable);
scene->addEntity(renderable);

The material instance is obtained from a material, itself loaded from a binary blob generated by matc:

Material* material = Material::Builder()
        .package((void*) BAKED_MATERIAL_PACKAGE, sizeof(BAKED_MATERIAL_PACKAGE))
        .build(*engine);
MaterialInstance* materialInstance = material->createInstance();

To learn more about materials and matc, please refer to the materials documentation.

To render, simply pass the View to the Renderer:

// beginFrame() returns false if we need to skip a frame
if (renderer->beginFrame(swapChain)) {
    // for each View
    renderer->render(view);
    renderer->endFrame();
}

For complete examples of Linux, macOS and Windows Filament applications, look at the source files in the samples/ directory. These samples are all based on samples/app/ which contains the code that creates a native window with SDL2 and initializes the Filament engine, renderer and views.

Java on Linux, macOS and Windows

After building Filament, you can use filament-java.jar and its companion filament-jni native library to use Filament in desktop Java applications. You can use Filament either with AWT or Swing, using respectively a FilamentCanvas or a FilamentPanel.

Following the steps above (how to use Filament from native code), create an Engine and a Renderer, but instead of calling beginFrame and endFrame on the renderer itself, call these methods on FilamentCanvas or FilamentPanel.

Android

Rendering with Filament on Android is similar to rendering from native code (the APIs are largely the same across languages). You can render into a Surface by passing a Surface to the createSwapChain method. This allows you to render to a SurfaceTexture, a TextureView or a SurfaceView. To make things easier we provide an Android specific API called UiHelper in the package com.google.android.filament.android. All you need to do is set a render callback on the helper and attach your SurfaceView or TextureView to it. You are still responsible for creating the swap chain in the onNativeWindowChanged() callback.

Generating C++ documentation

To generate the documentation you must first install doxygen, then run the following commands:

$ cd filament/filament
$ doxygen docs/doxygen/filament.doxygen

Finally simply open docs/html/index.html in your web browser.

Dependencies

One of our design goals is that Filament itself should have no dependencies or as few dependencies as possible. The current external dependencies of the runtime library include:

• STL
• robin-map (header only library)

Host tools (such as matc or cmgen) can use external dependencies freely.

How to make contributions

Please read and follow the steps in CONTRIBUTING.md. Make sure you are familiar with the code style.

License

Please see LICENSE.

Disclaimer

This is not an officially supported Google product.