ZTD

Zig Tower Defense

Status: Technological demo

About

This game was written by me during fall 2022 holidays to learn Zig and Data Oriented Design approach. It contains a highly optimized 2D sprite engine with custom OpenGL-based renderer.

To let the DOD shine, this project's goal was to push performance boundaries of the number of units present in the simulation. Currently on Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz the engine achieves up to 10*10^6 units/sec of single-threaded performance.

Runtime Requirements

• Linux with following packages: libglfw3-dev
• Windows 64

Usage

Start: ./ztd or ./ztd <level>. Available levels: level1, level2, level3, stress1

Keys:

• PgUp/PgDn, Mouse Wheel - zoom
• B - build mode
• ESC - exit build mode, clear selection
• q - quit

Development

Requirements:

• linux, libglfw3-dev package
• Zig 0.11 (I use zigup to fetch master version)

Commands:

• zig build
• zig build run
• zig build run -Drelease-fast=true -- [<level>]

Docker multiplatform build

./dev.sh dist will build linux and win64 release .zip archives.

Code Organization

Underlying data structures:

• src/geom.zig - 2d geometry primitives
• src/sparse_set.zig - sparse set implementation
• src/denset_set.zig - denset set implementation
• src/r_tree.zig - R Tree
• src/table.zig - fast table of records and table of bounds
• src/rects.zig - SIMD-friendly columnar []Rect

Game engine:

• src/gl.zig - OpenGL interface code
• src/imgui.zig - imgui interface code
• src/shaders.zig - opengl shaders utilities
• src/rendering.zig - different shader renderers
• src/sprites.zig - sprite atlas building and rendering
• src/viewport.zig - viewport calculations and update
• src/engine.zig - game engine
• src/engine_testbed.zig - simple testbed to debug the engine

Game:

• src/model.zig - model objects stored in table
• src/game.zig - game logic
• src/resources.zig - game resources
• src/levels.zig - game levels
• src/ui.zig - game UI and user interaction
• src/data.zig - units and buildings data (hp, damage, etc)
• src/main.zig - main entry poitn and game loop

License

• code in src/ is licensed under GPL3.
• code in lib/ is licensed under respective original licenses.
• mini world sprites are licensed under CC0
• rubik font is licensed under Open Font License

Screenshot