jBox3D

jBox3D provides Java bindings for Box3D, Erin Catto's 3D physics engine.

The project uses jParser WebIDL bindings over a small C/C++ wrapper layer, downloads upstream Box3D source into the build directory, generates Java/native glue, and packages runtime modules for desktop, web, and Android targets. It also includes libGDX and libFDX sample applications with Box3D-style sample selection, solver settings, debug rendering, picking, throwing, and camera controls.

The Java API is still evolving, but generated bindings, native builds, runtime packaging, extensions, samples, and a GitHub Pages web deployment workflow are in place.

Targets

Target	Modules	Notes
Core Java API	:box3d:base, :box3d:core	Hand-authored support plus generated Box3D API classes.
Box3D source download	:box3d:download	Downloads upstream Box3D source used by the builder.
Desktop JNI	:box3d:shared:jni, :box3d:desktop:jni	Native library packaging for Windows, Linux, and macOS.
Desktop FFM	:box3d:desktop:ffm	Java 25 FFM runtime for desktop.
Desktop C	:box3d:shared:c, :box3d:desktop:c	TeaVM C generated binding runtime used by the desktop C samples.
WebAssembly	:box3d:web:wasm	Emscripten WebAssembly runtime used by TeaVM browser samples.
Android JNI	:box3d:android:jni	Android JNI runtime packaging.
Android C	:box3d:android:c	Android TeaVM C runtime packaging.
libGDX GL extension	:extensions:gdx:gl	Base libGDX integration with allocation-free math conversions and ModelBatch debug rendering.
libGDX WebGPU extension	:extensions:gdx:wgpu	WebGPU-specific rendering support layered on the libGDX GL extension.
libFDX extension	:extensions:fdx	ModelBatch-based debug renderer support for libFDX samples.

The interop converters write into caller-owned output objects so they can be reused in render loops:

GdxBox3DConverter.toGdx(box3dVector, reusableGdxVector);
GdxBox3DConverter.toBox3D(gdxVector, reusableBox3dVector);

FdxBox3DConverter.toFdx(box3dVector, reusableFdxVector);
FdxBox3DConverter.toBox3D(fdxVector, reusableBox3dVector);

Samples

The shared Box3D sample logic lives in :samples:shared. The shared libGDX app/UI layer lives in :samples:gdx:shared, with renderer-specific cores in :samples:gdx:gl:core and :samples:gdx:wgpu:core.

Web version: https://xpenatan.github.io/jBox3D

libGDX WebGL sample launchers:

• :samples:gdx:gl:platforms:desktop-jni
• :samples:gdx:gl:platforms:desktop-ffm
• :samples:gdx:gl:platforms:desktop-c
• :samples:gdx:gl:platforms:web
• :samples:gdx:gl:platforms:android

libGDX WebGPU sample launchers:

• :samples:gdx:wgpu:platforms:desktop-jni
• :samples:gdx:wgpu:platforms:desktop-ffm
• :samples:gdx:wgpu:platforms:web
• :samples:gdx:wgpu:platforms:android

libFDX sample launchers:

• :samples:fdx:platforms:desktop-jni
• :samples:fdx:platforms:desktop-ffm
• :samples:fdx:platforms:desktop-c
• :samples:fdx:platforms:web
• :samples:fdx:platforms:android

Requirements

• JDK 25 for the full build and FFM/runtime validation.
• Android SDK for Android modules and samples.
• Emscripten for :box3d:builder:jParser_build_web_wasm.
• Platform native toolchains for desktop native builds: MSVC on Windows, clang/gcc on Linux, and Xcode command line tools on macOS.
• jParser, gdx-teavm, gdx-webgpu, and libFDX are consumed with -SNAPSHOT versions from Maven snapshots.

Native Build Driver

The download module downloads Box3D source into box3d/download/build/box3d-source. The builder module consumes that source, generates Java bindings, and builds native outputs through jParser.

.\gradlew.bat :box3d:download:box3d_download_source
.\gradlew.bat :box3d:builder:jParser_generate

Common native build tasks:

.\gradlew.bat :box3d:builder:jParser_build_windows64_jni
.\gradlew.bat :box3d:builder:jParser_build_windows64_ffm
.\gradlew.bat :box3d:builder:jParser_build_windows64_teavm_c
.\gradlew.bat :box3d:builder:jParser_build_web_wasm
.\gradlew.bat :box3d:builder:jParser_build_android_jni
.\gradlew.bat :box3d:builder:jParser_build_android_teavm_c

Equivalent jParser_build_* tasks exist for linux64, mac64, and macArm desktop targets. The builder also exposes the jParser iOS JNI task; settings.gradle.kts does not include an iOS runtime or sample module.

Running Samples

Desktop libGDX WebGL:

.\gradlew.bat :box3d:builder:jParser_build_windows64_jni
.\gradlew.bat :samples:gdx:gl:platforms:desktop-jni:box3d_gdx_desktop_jni_run

.\gradlew.bat :box3d:builder:jParser_build_windows64_ffm
.\gradlew.bat :samples:gdx:gl:platforms:desktop-ffm:box3d_gdx_desktop_ffm_run

.\gradlew.bat :samples:gdx:gl:platforms:desktop-c:box3d_gdx_desktop_c_run

Desktop libGDX WebGPU:

.\gradlew.bat :box3d:builder:jParser_build_windows64_jni
.\gradlew.bat :samples:gdx:wgpu:platforms:desktop-jni:box3d_gdx_wgpu_desktop_jni_run

.\gradlew.bat :box3d:builder:jParser_build_windows64_ffm
.\gradlew.bat :samples:gdx:wgpu:platforms:desktop-ffm:box3d_gdx_wgpu_desktop_ffm_run

Desktop libFDX:

.\gradlew.bat :box3d:builder:jParser_build_windows64_jni
.\gradlew.bat :samples:fdx:platforms:desktop-jni:box3d_fdx_desktop_gl_jni_run
.\gradlew.bat :samples:fdx:platforms:desktop-jni:box3d_fdx_desktop_wgpu_jni_run
.\gradlew.bat :samples:fdx:platforms:desktop-jni:box3d_fdx_desktop_vulkan_jni_run

.\gradlew.bat :box3d:builder:jParser_build_windows64_ffm
.\gradlew.bat :samples:fdx:platforms:desktop-ffm:box3d_fdx_desktop_gl_ffm_run
.\gradlew.bat :samples:fdx:platforms:desktop-ffm:box3d_fdx_desktop_wgpu_ffm_run
.\gradlew.bat :samples:fdx:platforms:desktop-ffm:box3d_fdx_desktop_vulkan_ffm_run

Desktop C samples use the current host C native target automatically. The default tasks link Box3D statically; the additional tasks exercise operating-system-linked and runtime-loaded shared libraries:

.\gradlew.bat :samples:gdx:gl:platforms:desktop-c:box3d_gdx_desktop_c_build
.\gradlew.bat :samples:gdx:gl:platforms:desktop-c:box3d_gdx_desktop_c_run
.\gradlew.bat :samples:gdx:gl:platforms:desktop-c:box3d_gdx_desktop_c_shared_linked_run
.\gradlew.bat :samples:gdx:gl:platforms:desktop-c:box3d_gdx_desktop_c_runtime_loaded_run
.\gradlew.bat :samples:fdx:platforms:desktop-c:box3d_fdx_desktop_gl_c_build
.\gradlew.bat :samples:fdx:platforms:desktop-c:box3d_fdx_desktop_wgpu_c_build
.\gradlew.bat :samples:fdx:platforms:desktop-c:box3d_fdx_desktop_vulkan_c_build

Web libGDX:

.\gradlew.bat :box3d:builder:jParser_build_web_wasm
.\gradlew.bat :samples:gdx:gl:platforms:web:gdx_teavm_web_js_run
.\gradlew.bat :samples:gdx:gl:platforms:web:gdx_teavm_web_wasm_run
.\gradlew.bat :samples:gdx:wgpu:platforms:web:gdx_teavm_web_js_run
.\gradlew.bat :samples:gdx:wgpu:platforms:web:gdx_teavm_web_wasm_run

Web libFDX:

.\gradlew.bat :box3d:builder:jParser_build_web_wasm
.\gradlew.bat :samples:fdx:platforms:web:box3d_fdx_webgl_js_run
.\gradlew.bat :samples:fdx:platforms:web:box3d_fdx_webgl_wasm_run
.\gradlew.bat :samples:fdx:platforms:web:box3d_fdx_webgpu_js_run
.\gradlew.bat :samples:fdx:platforms:web:box3d_fdx_webgpu_wasm_run

Android:

.\gradlew.bat :box3d:builder:jParser_build_android_jni
.\gradlew.bat :samples:gdx:gl:platforms:android:box3d_gdx_android_jni_run
.\gradlew.bat :samples:gdx:wgpu:platforms:android:box3d_gdx_wgpu_android_jni_run
.\gradlew.bat :samples:fdx:platforms:android:box3d_fdx_android_gles_run
.\gradlew.bat :samples:fdx:platforms:android:box3d_fdx_android_wgpu_jni_run
.\gradlew.bat :samples:fdx:platforms:android:box3d_fdx_android_vulkan_run

Android run tasks require adb from ANDROID_HOME, ANDROID_SDK_ROOT, local.properties, or PATH.

License

jBox3D is licensed under the Apache License 2.0.

Upstream Box3D is developed by Erin Catto and is licensed under the MIT license.