Dev on charalambous.uk

Teaching Terra to speak Lua

Mon, 13 Apr 2026 00:00:00 +0000

The game code has moved from C to Lua. Terra (the C engine) now exposes functions that Lua scripts call to spawn entities, move cameras, play sounds, and draw UI. The game itself is now a Lua script that the engine loads and runs.

The bridge

The Lua bridge is a single C file that wraps every engine system (renderer, input, audio, etc.) and exposes them as terra.* functions. I’ve got about 50 functions in here for now but I’m sure it will grow quite quickly as I start building larger games.

Vim inside a custom game engine

Mon, 13 Apr 2026 00:00:00 +0000

I embedded Neovim as a subprocess inside Terra. Neovim runs as nvim --embed --headless (no terminal or window).

First import

The first version was a bit rough but I have vim working inside the terra editor. You may also notice in this screenshot we have a ‘fake’ vim bar at the bottom which i was also experimenting with before importing vim, later we use the real one natively.

First Demo

Fri, 03 Apr 2026 00:00:00 +0000

This demo requires a keyboard and mouse.

Come back on a PC to play!

WASD move · Q cast
Scroll zoom · Esc pause

Pause to equip abilities
and adjust their values

From desktop to browser

Fri, 03 Apr 2026 00:00:00 +0000

Quite a few changes since the last post. It actually plays like a game and I have also configured a pipeline so that I can provide demos to play in a web browser.

Running in the browser

The entire engine compiles to WebAssembly via Emscripten using the same source code, same OpenGL calls. Emscripten translates them to WebGL 2.0 automatically. The total download is under 1MB, for comparison the google homepage is about 1.5MB total size.

Building a game and engine from scratch

Tue, 31 Mar 2026 00:00:00 +0000

Building a game from scratch. No Unity, no Unreal, no Godot. Just C, C++, and OpenGL. The project is codenamed Coopla, and the custom engine powering it is called Terra.

Game, engine & libraries

The engine is written in C17 with OpenGL 3.3. No massive framework with a load of stuff we will never need. Just enough to get pixels on screen and a player moving through 3D space.