Hydro engine and Oxygen editor

Overview

Hydro is where I learn engine technology by building it. It is a static library with three programs on top: Oxygen, the editor; Runtime, the standalone player that packaged games run on; and Game, the game's own code as native C++ scripts.

Rendering

A native Vulkan backend with explicit control over resources and synchronisation. The 2D path is the most mature; the 3D path is being built alongside it so both can share a scene.

2D

• Batched sprite and quad rendering, sprite animation, materials and textures
• Global and point lights with basic 2D shadows
• Multiple render views per frame, with separate editor and game views
• Shader hot reloading and GPU timing

3D

• Dynamic rendering, depth, GPU vertex and index buffers, perspective and orthographic cameras
• Directional, point and spot lights, emissive materials, ambient light and fog
• glTF and GLB import
• Sprites drawn inside 3D scenes as upright cut-out cards with depth, for mixed 2D and 3D scenes
• Entity-ID rendering for picking in the editor

Next: physically based materials and more post-processing.

Oxygen editor

A lightweight editor in the spirit of Unity and Godot, running directly on the engine.

• Scene and game viewports, hierarchy, inspector, project and asset browser, console
• Scenes, prefabs, saving and loading, project and render settings
• Play, pause, step one frame, and stop back to edit mode
• Engine and render statistics, debug drawing, entity picking
• Building a standalone game package from the File menu

Architecture

• ECS: EnTT, with components as plain data and systems that act on them
• Scripting: native C++ scripts with a reflection generator, so script fields show in the inspector and save with the scene
• Data: game content (dialogue, items, quests, enemies, abilities) as reflected definition files and tables, edited in the inspector
• Physics: Box2D for 2D; Jolt for 3D, with a capsule character controller, stairs, mesh colliders, ray and overlap queries, and triggers
• Subsystems: a fixed start-up and shutdown order, Init/Shutdown for subsystems and RAII for resources
• Build: premake, MSBuild scripts and a GitHub Actions pipeline that builds Debug and Release on every push

Eonlore: the game that proves it

Engine features are easy to demo and hard to prove. So Hydro has a real game to carry them: Eonlore, a tactical turn-based RPG with pixel-art characters in lit 3D scenes. Since November 2026 it lives in its own repository and builds against a pinned Hydro commit.

• Field scenes: the Shrine Glade, a temple and a town street, with NPCs, signs, chests and quests
• Turn-based battles built on turn order, elemental weaknesses, shields and Break
• In-game menus for inventory, character and quests, built on the runtime UI
• Every new engine system lands as a gameplay element in these scenes, not as a separate demo

Tooling and AI

Hydro is also where I develop my way of working with coding agents. The repository carries its own instructions, architecture skill and checks, so an agent can find its way around 500+ source files and verify its work before handing it back. Read about the AI workflow.

Status

Area	Status
2D engine and renderer	Working, used for gameplay
Scene, ECS, native scripting	Working
Oxygen editor	Working, expanding
Editor and game projects as separate projects	In progress now
Asset pipeline	Working foundation
3D rendering and import	In active development
3D physics (Jolt)	In active development
Audio, advanced post-processing	Planned