Kool vs LibGDX for Kotlin game development?

Kool offers modern graphics APIs like Vulkan and WebGPU, plus a built-in UI framework, while LibGDX is more established with a larger community but relies on older OpenGL. Choose Kool for cutting-edge rendering and web support, but expect a steeper learning curve due to less documentation.

How to load a 3D model in Kool?

Use Assets.loadGltfModel() with a GltfLoadConfig for customization. The engine fully supports glTF 2.0 with animations and skins, as demonstrated in the web demos featuring models like the Flight Helmet.

Does Kool work on iOS devices?

No, Kool does not natively support iOS. It targets desktop JVM, Android, and browsers via JavaScript/WebAssembly, so iOS would only be possible through a browser with limited functionality.

What browsers support Kool WebGPU demos?

Chrome is recommended for full WebGPU support; other browsers may fall back to WebGL, which doesn't support features like bloom or certain physics demos, as noted in the demo descriptions.

How to create a custom shader in Kool using KSL?

Use the KslShader DSL to define vertex and fragment stages in Kotlin, with examples like HelloKsl showing how to generate geometry and handle lighting. The code auto-compiles to backend-specific shader languages.

Is Kool's physics engine accurate for simulation games?

Yes, it uses Nvidia PhysX for 3D and Box2D for 2D, which are industry-standard libraries. The demos showcase realistic vehicle and ragdoll physics, but performance may vary on web targets due to JavaScript bindings.

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Kool

Apache-2.0Kotlinv0.19.0

A Kotlin multiplatform graphics engine supporting Vulkan, WebGPU, and OpenGL for desktop, Android, and web.

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What is Kool?

Kool is a multiplatform graphics engine written in Kotlin that provides a unified API for rendering 2D and 3D graphics across desktop, Android, and web. It abstracts underlying graphics APIs like Vulkan, WebGPU, and OpenGL, allowing developers to build games, simulations, and interactive applications with modern features such as PBR, physics, and a built-in UI framework.

Target Audience

Kotlin developers and game creators who need a high-performance, cross-platform graphics solution without managing low-level API differences. It's ideal for those building desktop games, Android apps, or browser-based demos with advanced rendering needs.

Value Proposition

Developers choose Kool for its seamless multiplatform support, expressive Kotlin DSL for shaders and UI, and integrated physics engine—all while maintaining high performance across Vulkan, WebGPU, and OpenGL backends.

Overview

A Vulkan / WebGPU / OpenGL engine for Desktop JVM, Android and Javascript written in Kotlin

Use Cases

Best For

Building cross-platform games with Kotlin
Creating browser-based 3D demos with WebGPU or WebGL
Developing Android apps with advanced graphics
Prototyping interactive simulations with physics
Writing shaders that work across multiple graphics APIs
Designing scenes with a built-in graphical editor

Not Ideal For

iOS or native macOS applications requiring Swift/Objective-C integration
Projects that demand extensive, beginner-friendly documentation and tutorials
Teams seeking a drag-and-drop game engine with a mature, full-featured scene editor
Applications heavily reliant on server-side rendering or non-graphical backend logic

Pros & Cons

Pros

Cross-Platform Graphics Abstraction

Supports Vulkan, WebGPU, and OpenGL backends, enabling deployment on desktop JVM, Android, and browsers with a single codebase, as highlighted in the platform support table.

Integrated Physics Simulation

Provides 3D physics via Nvidia PhysX and 2D via Box2D with consistent bindings for JVM and JavaScript, demonstrated in web demos like vehicle and ragdoll simulations.

Kotlin DSL for Shaders

KSL allows writing shaders in Kotlin that automatically compile to GLSL or WGSL, ensuring cross-backend compatibility without platform-specific code, as shown in the HelloKsl example.

Built-In UI Framework

Features a Compose-inspired UI system that runs within the engine, enabling rich interfaces without external dependencies, evidenced by the embedded UI demo and editor.

Cons

Sparse Documentation

The README admits documentation is a weak spot, which can hinder onboarding and troubleshooting for developers new to the engine.

WebGPU-Only Features

Advanced demos like bloom, pathtracing, and vehicle physics require WebGPU, limiting functionality on browsers without support and creating fragmentation.

Immature Scene Editor

The built-in graphical editor is in an early state and lacks essential features, making it unsuitable for complex production-level scene design.

Complex IDE Setup

Running demos in IntelliJ requires manual build steps and gradle re-syncs, adding friction to the development workflow compared to plug-and-play engines.

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