PlayerInputComponent

Location: shared/include/components/PlayerInputComponent.hpp (planned)

The PlayerInputComponent stores the latest validated input state for a player entity. The server remains authoritative; these values are used for reconciliation and orientation.

Structure

struct PlayerInputComponent {
    float x = 0.0F;                // Client-reported position X (center)
    float y = 0.0F;                // Client-reported position Y (center)
    float angle = 0.0F;            // Client aim/ship angle (radians, 0 along +X, CCW)
    std::uint16_t sequenceId = 0;  // Last processed input sequence number
};

Fields

Field	Type	Default	Description
`x`	`float`	`0.0F`	Client-reported position estimate (for reconciliation)
`y`	`float`	`0.0F`	Client-reported position estimate (for reconciliation)
`angle`	`float`	`0.0F`	Client aim/ship angle in radians
`sequenceId`	`uint16_t`	`0`	Sequence number for input ordering

Invariants

Finite values for x, y, angle
sequenceId monotonically increases per client

Usage

Server Receiving Input

// Network thread receives UDP packet with input
PlayerInput incomingInput = deserializeInput(packet);

auto& input = registry.get<PlayerInputComponent>(playerId);

// Validate and apply
if (incomingInput.sequenceId > input.sequenceId) {
    input.x = incomingInput.x;
    input.y = incomingInput.y;
    input.angle = incomingInput.angle;
    input.sequenceId = incomingInput.sequenceId;
}

PlayerSystem Processing

for (EntityId id : registry.view<TransformComponent, PlayerInputComponent>()) {
    auto& transform = registry.get<TransformComponent>(id);
    auto& input = registry.get<PlayerInputComponent>(id);

    // Server-authoritative movement
    transform.rotation = input.angle;  // Apply client's aim direction

    // Validate and apply position (with server checks)
    if (isValidPosition(input.x, input.y)) {
        transform.x = input.x;
        transform.y = input.y;
    }
}

Networking

Inbound only — Received from owning client, never broadcast to others
Server validates — All inputs checked for cheating/invalid values
Sequence IDs — Prevent replay attacks and ensure ordering

Client-Server Reconciliation

Client sends: Position + input + sequence ID
Server validates: Checks bounds, speed limits
Server applies: Updates authoritative position
Server responds: Sends confirmed position back
Client reconciles: Adjusts local simulation if mismatch

Systems

NetworkSystem — Receives and deserializes inputs
PlayerSystem — Consumes inputs to update player state
MovementSystem — May consult for movement validation