Develop Gameplay Systems

Implement modular, testable gameplay systems and character controllers that maintain deterministic simulation, clean component boundaries, and strict frame-rate independence.

Core Rules

• Fixed Timestep Determinism: Always update physics, collision detection, and spatial queries inside fixed tick loops (_physics_process in Godot, FixedUpdate in Unity, sub-stepped ticks in Unreal/custom engines). Never bind movement speed directly to variable render delta times.
• Hierarchical State Isolation: Model player states (Idle, Run, Jump, Fall, Attack, Stunned) via explicit state machines. Transitions must be driven by verified inputs and conditions, never by ambient variable mutations.
• Zero GC in Hot Loops: Pre-allocate collision queries, raycast hit buffers, and vectors. Do not instantiate heap objects, closures, or temporary arrays inside update loops.
• Contract Adherence: Emit contracts/schemas/implementation-result.json when completing gameplay system slices.

Suggested Process

1. Frame Budget & Timestep Setup

Define target fixed tick rate ($60\text{Hz}$ or $120\text{Hz}$). Ensure kinematic velocity integration follows: $$\vec{x}_{t+1} = \vec{x}_t + \vec{v}t \cdot \Delta t{\text{fixed}}$$ Apply gravity and terminal velocity limits consistently.