RUDPClient/openspec/specs/client-gameplay-input/spec.md

client-gameplay-input Specification

Purpose

Define how the controlled Unity client captures MVP gameplay intent, preserves immediate local prediction, and sends movement and shooting through split gameplay messages.

Requirements

Requirement: Controlled client movement input preserves immediate prediction and explicit stop signaling

The MVP client SHALL capture movement intent for the controlled player in Unity-side input code, apply local movement prediction immediately, and send MoveInput updates through the networking boundary. When movement input transitions from non-zero to idle, the client MUST send one final zero-vector MoveInput so authoritative movement can stop cleanly.

Scenario: Controlled player moves locally without waiting for the network

• WHEN the controlled player provides non-zero movement input
• THEN the client applies local movement prediction immediately for presentation
• THEN the client submits a MoveInput carrying the current player id, tick, and planar movement vector through the networking send path

Scenario: Releasing movement emits an explicit stop update

• WHEN the controlled player releases movement input after previously providing non-zero movement
• THEN the client sends exactly one final MoveInput whose movement vector is zero
• THEN local predicted movement also stops immediately without waiting for authoritative correction

Requirement: Controlled client captures shooting intent as a dedicated gameplay input

The MVP client SHALL capture local fire intent separately from movement and translate that intent into ShootInput messages rather than overloading movement or generic gameplay-action payloads.

Scenario: Firing produces a shoot input message

• WHEN the controlled player triggers a fire action
• THEN the client constructs a ShootInput containing the current player id, tick, and aim direction used by the MVP client flow
• THEN the message is sent through a dedicated shooting send path instead of a legacy generic gameplay-action message

Requirement: Local shooting presentation remains cosmetic

The MVP client SHALL treat any immediate local shooting feedback as optional cosmetic presentation and MUST NOT use it to finalize authoritative combat outcomes.

Scenario: Cosmetic firing feedback does not decide gameplay truth

• WHEN the client plays local muzzle flash, animation, or similar fire feedback before server confirmation
• THEN that feedback does not apply authoritative damage, hit confirmation, or death resolution locally
• THEN gameplay truth remains dependent on authoritative server messages