Optimizing Living Cities in Corsairs Legacy for Steam Deck and Low-End PCs

For the Tech-5 UG and Corsairs Legacy team, one of the biggest technical challenges was finding the right balance between:

• visual realism
• CPU performance
• memory usage
• and Steam Deck compatibility

A living Caribbean city needs crowded streets, moving civilians, taverns, markets, sailors, guards, and dynamic interactions. But every NPC comes with a significant technical cost.

Why NPCs Are Expensive

Each dynamic NPC in Corsairs Legacy requires:

• skeletal animation updates
• AI behavior processing
• pathfinding calculations
• navigation mesh interaction
• collision checks
• animation blending
• and CPU updates every frame

Modern character rigs may contain dozens of bones per character, and when multiplied across large cities, performance costs increase very quickly.

On lower-end hardware — especially handheld devices like the Steam Deck — this becomes a major bottleneck.

The Challenge

The goal was not simply reducing NPC counts.

The real challenge was preserving the illusion of a fully alive city while dramatically reducing the amount of simulation happening at the same time.

The system also had to avoid obvious “pop-in” effects or streets suddenly becoming empty when graphics settings changed.

Dynamic NPC Streaming System

To solve this problem, the team developed a custom dynamic NPC streaming system.

Instead of simulating every NPC on the island simultaneously:

• only NPCs near the player are fully active
• while distant NPCs are unloaded or virtualized

This means:

• nearby NPCs continue walking, talking, and reacting
• while distant NPCs stop consuming gameplay-related CPU resources

Outside the active simulation radius:

• animations are paused
• AI updates stop
• movement calculations are disabled
• and NPCs can be dynamically repositioned between city zones

As a result, the world still appears populated and believable from the player’s perspective, while the engine avoids simulating hundreds of unnecessary characters.

Camera-Based Optimization

An interesting side effect of this system can be seen in Photo Mode.

Since the optimization logic is centered around the player position rather than the free camera, flying far away from the player may reveal areas of the island with significantly fewer active NPCs.

This is intentional.

The system prioritizes runtime gameplay performance instead of maintaining full simulation across the entire map simultaneously.

Smart NPC Density Scaling

Another important goal was making graphics settings affect performance — not immersion.

Traditional NPC density systems often make cities feel obviously empty on lower settings.

Instead, Corsairs Legacy scales:

• the amount of actively simulated NPCs
• the update frequency
• and the active AI population around the player

For example:

• High settings may allow around 100 active civilian NPCs nearby
• while Low settings may simulate closer to 40

However, thanks to spawn distribution logic and streaming rules, the city still visually feels alive and populated.

Designed for Steam Deck

These optimizations became especially important for achieving stable performance on Steam Deck.

Handheld hardware has far tighter CPU and power limitations compared to desktop PCs, meaning every unnecessary animation update or AI calculation matters.

By aggressively optimizing NPC simulation while preserving visual density, the team was able to keep large cities believable without sacrificing performance.

Building Living Worlds Efficiently

For the Tech5 team, the challenge was never simply “adding more NPCs.”

The real engineering challenge was deciding:

• which NPCs actually need simulation
• when they should consume resources
• and how to preserve immersion while dynamically reducing CPU load behind the scenes

The final system allows Corsairs Legacy to maintain large, lively Caribbean cities while still remaining scalable across a wide range of hardware configurations.