jJolt

jJolt is a Java binding for the C++ library Jolt Physics, utilizing JNI/FFM for desktop, JNI for Android, and Emscripten for web platforms. It provides a one-to-one correspondence with the C++ code, meaning it mirrors the exact same class and method names. Its libfdx samples consume the jolt_ext adapter owned and published by libFDX.

The binding leverages jParser, a custom C/C++ build tool and WebIDL Java code generator, which automatically generates 99% of all classes. Only a small number of essential classes are coded manually, making updates to new Jolt Physics versions quick and efficient.

• Jolt-Samples-GL

• Yes: Have a working build.
• No: Build not ready.

// Use -SNAPSHOT or any released git-tag version.

// Add repository to root Gradle.
repositories {
    mavenLocal()
    mavenCentral()
    maven { url "https://central.sonatype.com/repository/maven-snapshots/" }
}

// Core module
implementation("com.github.xpenatan.jJolt:core:-SNAPSHOT")
implementation("io.github.libfdx:jolt_ext:-SNAPSHOT")
implementation("io.github.libfdx:application:-SNAPSHOT")
implementation("io.github.libfdx:g3d:-SNAPSHOT")

// Desktop module
dependencies {
   implementation("com.github.xpenatan.jJolt:desktop-jni:-SNAPSHOT")
   implementation("com.github.xpenatan.jJolt:desktop-ffm:-SNAPSHOT")
   implementation("io.github.libfdx:backend_desktop:-SNAPSHOT")
   implementation("io.github.libfdx:gl_desktop:-SNAPSHOT")
   implementation("io.github.libfdx:vulkan_desktop:-SNAPSHOT")
   implementation("io.github.libfdx:wgpu_desktop_jni:-SNAPSHOT")
   implementation("io.github.libfdx:wgpu_desktop_ffm:-SNAPSHOT")
}

// TeaVM module
dependencies {
   implementation("com.github.xpenatan.jJolt:web-wasm:-SNAPSHOT")
   implementation("io.github.libfdx:backend_web:-SNAPSHOT")
   implementation("io.github.libfdx:gl_web:-SNAPSHOT")
   implementation("io.github.libfdx:wgpu_web:-SNAPSHOT")
}

// Android module
dependencies {
   implementation("com.github.xpenatan.jJolt:android-jni:-SNAPSHOT")
   implementation("io.github.libfdx:backend_android:-SNAPSHOT")
   implementation("io.github.libfdx:wgpu_android_jni:-SNAPSHOT")
   implementation("io.github.libfdx:vulkan_android_jni:-SNAPSHOT")
}

• Use JoltSettings and JoltInterface for lifecycle management. JoltInterface initializes Jolt, owns the physics system, allocator, job system, and the three collision-filter objects supplied through settings, and shuts them down in the correct order. Objects returned by its getters are borrowed.
• In most classes, new instances are created using JoltNew.[TYPE] instead of standard Java constructors. This approach is necessary due to limitations in constructor overloading within WebIDL when targeting Emscripten.
• Methods that return an object typically return a temporary object. You should not retain a reference to it, as calling the method again with another instance will overwrite the previously returned object.
• Classes are not disposed automatically; the dispose method must be called when they are no longer in use. However, classes in a WebIDL file marked with NoDelete do not require disposal.

• Java 17 or later
• Gradle
• Android NDK (only needed for Android native artifacts)
• Mingw64 or Visual Studio C++ (only needed for desktop native artifacts)
• Emscripten (only needed for WebAssembly native artifacts)

The samples use the local jJolt projects by default. To run either the libGDX or libfdx samples with published artifacts instead, enable the global switch:

# Use the snapshot version configured by exampleVersion in gradle/libs.versions.toml.
./gradlew -PuseRepoLibs=true :samples:gdx:gl:platforms:desktop-jni:jolt_samples_run_desktop

# Test a release without editing the version catalog.
./gradlew -PuseRepoLibs=true -PexampleVersion=RELEASE_VERSION :samples:fdx:platforms:desktop-jni:jolt_sample_desktop_gl_jni_run

You can also set useRepoLibs = "true" and change exampleVersion in gradle/libs.versions.toml. Published mode uses Maven artifacts for Jolt core and platform natives. The libfdx samples always consume the separately published io.github.libfdx:jolt_ext snapshot.

• Desktop JNI: ./gradlew :samples:gdx:gl:platforms:desktop-jni:jolt_samples_run_desktop
• Desktop TeaVM/C: ./gradlew :samples:gdx:gl:platforms:desktop-c:jolt_gdx_desktop_c_run
• Web: ./gradlew :samples:gdx:gl:platforms:web:jolt_samples_run_teavm
• Android: ./gradlew :samples:gdx:gl:platforms:android:assembleDebug

• Desktop OpenGL/JNI: ./gradlew :samples:fdx:platforms:desktop-jni:jolt_sample_desktop_gl_jni_run
• Desktop WGPU/JNI: ./gradlew :samples:fdx:platforms:desktop-jni:jolt_sample_desktop_wgpu_jni_run
• Desktop WGPU/FFM: ./gradlew :samples:fdx:platforms:desktop-jni:jolt_sample_desktop_wgpu_ffm_run
• Desktop Vulkan/JNI: ./gradlew :samples:fdx:platforms:desktop-jni:jolt_sample_desktop_vulkan_jni_run
• Desktop Vulkan/FFM: ./gradlew :samples:fdx:platforms:desktop-jni:jolt_sample_desktop_vulkan_ffm_run
• WebGL JS/Wasm: ./gradlew :samples:fdx:platforms:web:jolt_sample_webgl_js_build :samples:fdx:platforms:web:jolt_sample_webgl_wasm_build
• WebGPU JS: ./gradlew :samples:fdx:platforms:web:jolt_sample_webgpu_js_build
• Android GLES/WGPU/Vulkan: ./gradlew :samples:fdx:platforms:android:jolt_sample_android_gles_build :samples:fdx:platforms:android:jolt_sample_android_wgpu_jni_build :samples:fdx:platforms:android:jolt_sample_android_vulkan_build

./gradlew :jolt:download:jolt_download_source

# Generate binding sources for JNI, FFM, and web.
./gradlew :jolt:builder:jParser_generate

# Generate and build native platform targets.
./gradlew :jolt:builder:jParser_build_windows64_jni :jolt:builder:jParser_build_windows64_ffm :jolt:builder:jParser_build_windows64_teavm_c
./gradlew :jolt:builder:jParser_build_linux64_jni :jolt:builder:jParser_build_linux64_ffm :jolt:builder:jParser_build_linux64_teavm_c
./gradlew :jolt:builder:jParser_build_mac64_jni :jolt:builder:jParser_build_mac64_ffm :jolt:builder:jParser_build_mac64_teavm_c
./gradlew :jolt:builder:jParser_build_macArm_jni :jolt:builder:jParser_build_macArm_ffm :jolt:builder:jParser_build_macArm_teavm_c
./gradlew :jolt:builder:jParser_build_android_jni
./gradlew :jolt:builder:jParser_build_web_wasm