🧵 Object Pooling vs. Instantiate/Destroy

About this simulation

Real-time simulations and games spawn and remove huge numbers of short-lived objects — bullets, particles, enemies, floating combat text. The naive approach calls new (allocate geometry, material, buffers) every time an object appears and throws it away when it disappears, leaving the job of reclaiming that memory to the garbage collector. The object pool pattern instead pre-allocates a fixed set of objects once, and "spawning" just means pulling an idle one out of the pool and resetting its state — no allocation, no garbage, ever.

How it works

• The left scene creates a brand-new mesh (geometry + material) on every spawn and disposes it on despawn — real allocation and deallocation work each cycle.
• The right scene draws from a fixed-size pool created once at startup; spawning only toggles visibility and resets a transform — zero allocations after warm-up.
• The graph plots the actual JavaScript time spent inside each side's per-frame update function, measured with performance.now().
• As spawn rate and "GC pressure" rise, the naive line grows taller and spikier while the pooled line stays low and flat — the same shape you'd see in a Unity or Unreal profiler comparing raw Instantiate/Destroy against a pooling system.

Controls

• Spawn rate — objects launched per second on both sides.
• Object lifetime — how long each projectile lives before despawning.
• GC pressure — extra throwaway data the naive side allocates per spawn, simulating heavier per-object state.
• Pool capacity — maximum concurrent objects the pooled side can hold before it starts recycling the oldest.
• ↺ Reset both scenes — clears all active objects. Drag to rotate, scroll to zoom (applies to both halves).

Did you know?

This is also why data-driven engines pair pooling with something like Unity's ScriptableObject — shared, read-only configuration data (colors, speeds, stats) lives once in memory and is referenced by every pooled instance instead of being copied and re-copied on every spawn.