A 2D top-down roguelike shooter — and the game engine underneath it — written from scratch in Java.

Descend floor by floor through a procedurally generated dungeon, kill everything in the room, spend what drops, and get a little further than last run. There is no third-party game engine here — the renderer, the audio, the collision system, the pathfinding, the map generator and the netcode are all part of this repository, sitting directly on top of LWJGL and OpenGL.

It started as a small side project and grew considerably past that.

Showcase

Pre-0.9 — artefacts, boss fights, floor affixes	Pre-0.8 — lighting, particles, shop
0.3 — weapons, minimap, room generation	0.2.2 — the early engine

_{Click any frame to watch the run on YouTube.}

The run

Every floor is generated fresh: a starter room, a handful of combat rooms, a loot room, a shop and a boss room, stitched together with corridors and revealed on the minimap as you clear them. Entering a room locks the doors until the last enemy is down. The ladder appears when the boss dies, and the next floor is harder — enemy health scales by 12 × floor² percent.

Between runs you land in the progress room, where an NPC sells permanent upgrades for the coins you carried out. Those upgrades — and your coin balance — live in a local SQLite database, so they survive death.

Floor affixes

Each floor rolls its own modifiers, shown on the title card as you walk in.

Affix	Effect
Rare potions	Healing potion drops get rerolled — expect to find far fewer
Inflation	Shop prices doubled
Fortified	Enemy health ×1.4, on top of the floor scaling
Raging	Enemies below 20% health speed up by 30%
Regeneration	Enemies heal 2% of their max health every 5 seconds

Arsenal

Nine weapons, two carried slots, each with its own upgrade track in the progress room.

Pistol · Luger · Revolver · Shotgun · Modern shotgun · Uzi · Thompson · M4 · Grenade launcher

Bestiary

Slime · Red slime · King slime (boss) · Rat · Bat · Eyebat · Demoneye · Ghost · Golem · Snake

Enemies pathfind to you around walls and obstacles, and several of them shoot back with their own projectile types.

Artefacts

Active items with charges, found on the floor or bought from the shopkeeper.

Damage	Support	Special
Rage potion	Ammo belt	Lucky coin
Ring of fire	Berserk potion	Revive book
	Shield horn	Trophy
	Armor potion

Rooms also fight back on their own: barrels, pots and crystals that break, spikes, arrow traps and flamethrowers that do not care whose side you are on.

The engine

Area	What it does
Rendering	Modern OpenGL 3.0+ — VBOs, instanced draw calls for bullets and particles, sprite sheet animation, an autotiling tilemap
Shaders	15 GLSL programs: geometry, instancing, lighting, outlines, blur, fade, spawn effects, health bars, text, weapon rotation
Post-processing	Dynamic per-light rendering, gaussian blur, screen fades, vignettes for blind and armor states
Audio	OpenAL through LWJGL — positional effects, music tracks, independent volume for music and effects
Physics	AABB tilemap collision, SAT for rotated hitboxes, knockback and separation between entities
AI	A* over the room grid, with line-of-sight, states and per-enemy attack behaviour
Map generation	Random room graph per floor, room templates loaded from .map files, corridor carving, autotiling, minimap
Persistence	SQLite over JDBC for coins and weapon upgrade levels
Game loop	Frame-rate independent, delta-time driven, with a loading screen that streams textures and audio up front
Extras	Discord Rich Presence, in-game screenshots, remappable controls, resolution and brightness settings

Algorithms

AABB	Tilemap and entity collision
A*	Enemy pathfinding
SAT	Rotated / oriented hitboxes

Multiplayer

Co-op over KryoNet on port 54555, with an authoritative server that owns enemies, drops and map generation. It works, but it is not finished — expect rubber-banding under latency.

	Status
Client interpolation	✅ Done
Client input prediction	🟦 In progress
Client lag compensation	🟦 Planned
Server lag compensation	🟦 Planned

Controls

Action	Default		Action	Default
Move	W A S D		Weapon slots	1 2
Shoot	Left mouse		Drop weapon	Q
Reload	R		Interact	E
Map	Tab		Use artefact	F

All of them are remappable from the in-game settings.

Running it

Requirements

• Windows. Only Windows LWJGL natives are vendored in libraries/, and asset paths across the codebase are written with backslashes, so a Linux or macOS run will not find its textures.
• JRE 1.8+ and a GPU supporting OpenGL 3.0+.
• ~250 MB RAM for singleplayer, 500 MB+ for multiplayer.
• Maven to build from source.

Build

mvn clean package dependency:copy-dependencies

The LWJGL native classifier is picked automatically by the Maven profiles in pom.xml (natives-windows, natives-windows-x86, natives-linux).

Run

java -Djava.library.path=libraries -cp "target/Bane-0.9.jar;target/dependency/*;libraries/*" cz.Empatix.Main.Game

Run it from the repository root. Textures/, Sounds/, shaders/ and resources/ are resolved relative to the working directory, and data.db and settings.cfg are written there.

Project layout

Path	What lives there
src/main/java/cz/Empatix/Main	Entry point, window and GLFW setup, input, settings, Discord RPC
src/main/java/cz/Empatix/Render	Renderer, camera, tilemap, rooms, HUD, minimap, text, post-processing
src/main/java/cz/Empatix/Entity	Player, enemies, item drops, artefacts, room objects, A* pathfinding
src/main/java/cz/Empatix/Guns	Weapons and projectiles
src/main/java/cz/Empatix/Gamestates	Menu, singleplayer and multiplayer states, progress room
src/main/java/cz/Empatix/Multiplayer	KryoNet client and server, packets, interpolation
src/main/java/cz/Empatix/AudioManager	OpenAL wrapper, soundtracks and effects
src/main/java/cz/Empatix/Buffs	Berserk, rage, poison, blindness
src/main/java/cz/Empatix/Database	SQLite persistence
shaders/	GLSL vertex and fragment shaders
Textures/, Sounds/	Sprite sheets, bitmap font, music and effects
resources/Map/	Hand-authored room templates for the generator
libraries/	Vendored LWJGL natives, KryoNet, Discord RPC, SQLite JDBC

License

GNU GPL v3.