Building a Browser FPS from Scratch: Sicar.io and the Lumina.pw Engine

Hoodgail Benjamin — Fri, 10 Oct 2025 06:24:58 +0000

I've been heads‑down on Sicar.io, a fast, skill‑forward FPS that runs entirely in the browser. This devlog is a look behind the curtain: how the game came together and how I've been building Lumina.pw, the custom web engine powering it.

Creating a real‑time 3D multiplayer shooter for the web has been equal parts thrilling and stubborn. Browsers were not born for this, but with the right tricks they can sprint.

Foundations: the Lumina.pw Engine

The goal from day one was simple to say and hard to do: prove a high‑performance FPS can live natively in the browser. That meant building Lumina.pw from scratch with WebGL for rendering and JavaScript for game logic. Every feature in Sicar.io pulled a matching feature into the engine, and vice‑versa.

Watch: Procedural Cycle, Dynamic Lighting, Outdoor Lighting, Pre-generated Particles

Core Mechanics: Recoil & Shooting

July 7, 2024 — Recoil system (WIP)

I started with recoil because it defines how the game feels under pressure. Competitive shooters need predictable‑enough patterns that skilled players can learn, without turning the gun into a metronome. A pure sinusoid was too readable; the current design blends a learnable base pattern with bounded variance so it stays manageable and still feels alive.

Watch: Recoil video

August 20, 2024 — Movement + early shooting preview

Hooking up movement to the first pass at shooting exposed the usual gremlins:

IK limits were clamping arm/hand reach beyond what the pose needed.
Animation swapping from fire → idle snapped instead of easing.

Catching those early saved a lot of downstream tuning.

Watch the clip: FPS Movement & Shooting Mechanics Preview (unlisted)

Making the World Breathe: AI Systems

September 12, 2024 — Bot pass

To keep play meaningful without a full lobby, I built a lightweight bot layer: navigate, acquire, engage. It runs entirely on engine primitives so I can profile pathing and targeting costs in the same environment as players.

Watch: AI Bot System in Action

First‑Person Polish: Inverse Kinematics

January 10, 2025 — Right‑arm IK

Convincing first‑person hands are 90% of perceived quality. I implemented a right‑arm IK chain that keeps the weapon aligned while allowing separate reload and fire animations to play concurrently. The target was fluidity in the vein of DOOM/Tarkov: responsive, but not floaty.

Watch: IK Testing in engine with character rig

Smarter NPCs: Movement & Navigation

August 31, 2025 — Point‑and‑click navigation

Building on the bot work, I added a simple point‑and‑click navigation showcase to stress test pathfinding, steering, and obstacle handling under engine timing.

Demo: Simple NPC Movement System Showcase

Latest Build: Alpha Gameplay

October 10, 2025 — Alpha snapshot

Here's a current slice with recoil, refined animations, and base AI all running on Lumina.pw in‑browser.

Watch: Sicar.io Alpha Gameplay — Fast‑paced, precise

What's Next

Tighten recoil tuning and expose per‑weapon curves.
Expand animation state machine (partial‑body blends, better transitions).
Broaden bot behaviors and map interaction.
Keep pushing frame time down on mid‑tier hardware.

Feedback is fuel. If you're curious about any part of Lumina.pw or Sicar.io—rendering, IK, networking, or AI—tell me what you'd like to see next.

Forem: Hoodgail Benjamin

Building a Browser FPS from Scratch: Sicar.io and the Lumina.pw Engine (Devlog)