Optimizing High-Fidelity Physics on Mobile

Achieving 60 FPS on budget hardware while maintaining complex physics interactions requires abandoning standard paradigms and embracing data-oriented design.

01. The Bottleneck

Unity's default PhysX engine is powerful, but computationally expensive when not optimized for mobile architecture. Scaling to 500+ active debris objects in "Cyber Breaker" resulted in a drastic frame rate drop to 15 FPS on our target test hardware (Galaxy A12).

Detailed profiler analysis confirmed that Physics.Simulate was consuming nearly 40% of the entire frame budget. It became clear that a standard optimization approach—simply reducing object counts—would compromise the game's core visual identity.

02. Object Pooling V2

Standard instantiation and destruction cycles cause significant garbage collection spikes, which manifest as micro-stutters during gameplay. We implemented a custom ring-buffer pool. This allows debris entities to be reused without hierarchy reparenting, eliminating costly transform updates and keeping memory allocation completely flat during runtime.

By pre-allocating memory and avoiding the overhead of the Unity hierarchy where possible, we achieved near-zero allocation during intense debris sequences.

03. Visual Simulation vs Physical Accuracy

Heuristic: Not every visual object requires a physical collider. For background explosions and distant effects, we utilize GPU instancing and vertex shaders. The visual fidelity remains consistent with the foreground physics, but the CPU cost for these elements is effectively reduced to zero.

We use local physics for objects immediate to the player's interactable zone, while switching to purely kinematic or shader-based movement for particles outside the immediate gameplay impact area. This "LOD for Physics" approach is critical for mobile scalability.

04. Final Performance Metrics

After implementing these optimizations, "Cyber Breaker" maintained a stable 58-60 FPS even during peak destruction phases on entry-level Android devices. More importantly, thermal throttling was significantly delayed, extending playable session times by 40%.

• [>] AVG FPS: 58-60 (Target Alpha)
• [>] BATTERY DRAIN: Optimized (-15%)
• [>] MEMORY ALLOC: STABLE / ZERO LEAK