Files
CosmicClash/Game/scripts/match_sim.gd
T
Josh Creek 7b150ef72e feat(multiplayer): task 2.8 net_sim.gd, close out Phase 2
New NetSim autoload: seeded, CLI-driven (--net-sim-latency/-jitter/-loss/-dup)
latency/jitter/loss/duplicate decorator, a true no-op passthrough unless a
flag is set. Wraps MatchSim.send_input/send_snapshot per the design doc's
scope, plus NetworkManager's ping/pong so the already-tested RTT/clock
measurement becomes the acceptance signal for "raises observed RTT" without
waiting on Phase 3's per-peer snapshot echo.

Two real bugs found while building and verifying this against Phase 2's own
milestone gate (a real match under --net-sim-latency 80 --net-sim-jitter
20, not just LAN): a timestamp captured inside a delayed RPC closure
silently ate that side's own added delay out of the round-trip
measurement instead of adding to it; and a delayed send whose target
disconnected (or whose own process had already shut down) during the hold
threw RPC errors, since the existing get_peers() filtering only checked
validity at schedule time. Fixed by capturing timestamps before handing
off to NetSim, and by having NetSim re-validate the target at fire time.

Phase 2's milestone gate now passes for real: a full 1v1 under simulated
80ms latency / 20ms jitter still shows clean server-authoritative
movement and zero RPC errors. Full Phase 1 + Phase 2 regression suite
re-verified clean with NetSim present but inactive.
2026-08-20 08:50:47 +01:00

98 lines
4.2 KiB
GDScript

extends Node
# Autoload (project.godot [autoload] MatchSim). Phase 2 simulation RPCs:
# match_config (server assigns arena + deterministic slot order from
# MatchNet.roster), input (client -> server, per-tick action), snapshot
# (server -> client, NetCodec-packed body state), and a small score_update
# for the HUD. Lives on an autoload per §1.3's derived decision ("All
# hot-path RPCs live on autoloads") even though these are scoped to
# whichever match happens to be running — a scene-node RPC target would
# need matching NodePaths across peers, which an autoload sidesteps
# entirely, and it's what lets NetworkedMatch itself stay a plain scene
# node with no networking-identity concerns of its own.
#
# Channel intent per §2.1: 0 reliable (match_config, score_update), 1
# unreliable-ordered (input), 2 unreliable-ordered (snapshot) — not yet
# verified against ENet's own reserved system channel offset (§2.1's own
# "verify empirically" hedge); if that turns out to matter these indices
# will need adjusting, not the RPC design itself.
const NetCodec = preload("res://scripts/net_codec.gd")
signal match_config_received(arena_path: String, peer_ids: PackedInt32Array, teams: PackedInt32Array, spawn_indices: PackedInt32Array)
signal input_received(peer_id: int, decoded: Dictionary) # decoded: see NetCodec.unpack_input
signal snapshot_received(decoded: Dictionary) # decoded: see NetCodec.unpack_snapshot
signal score_update_received(score: Dictionary)
# Server only: the last match_config actually sent, so a client whose own
# scene load (and therefore its match_config_received listener) finishes
# AFTER the server already broadcast can still get it — a one-shot
# broadcast alone is racy against however long the client takes to reach
# the point where it's listening, and Godot signals never buffer for a
# late connection. request_match_config() closes that race by turning
# delivery into "ask until you get it" instead of "hope you were already
# listening." Also covers a late joiner mid-match (Phase 5 will still need
# to add live match *state*, not just this static config, for that case).
var _last_match_config: Dictionary = {}
func send_match_config(arena_path: String, peer_ids: PackedInt32Array, teams: PackedInt32Array, spawn_indices: PackedInt32Array) -> void:
_last_match_config = {
"arena_path": arena_path, "peer_ids": peer_ids, "teams": teams, "spawn_indices": spawn_indices,
}
_match_config.rpc(arena_path, peer_ids, teams, spawn_indices)
func request_match_config() -> void:
_request_match_config.rpc_id(1)
func send_input(bytes: PackedByteArray) -> void:
# bytes is already fully packed (any timestamps it carries are already
# fixed), so wrapping the dispatch itself is enough — task 2.8.
NetSim.send(func() -> void: _recv_input.rpc_id(1, bytes), 1)
func send_snapshot(peer_id: int, bytes: PackedByteArray) -> void:
NetSim.send(func() -> void: _snapshot.rpc_id(peer_id, bytes), peer_id)
func send_score_update(score: Dictionary) -> void:
_score_update.rpc(score)
@rpc("authority", "call_remote", "reliable", 0)
func _match_config(arena_path: String, peer_ids: PackedInt32Array, teams: PackedInt32Array, spawn_indices: PackedInt32Array) -> void:
match_config_received.emit(arena_path, peer_ids, teams, spawn_indices)
@rpc("any_peer", "call_remote", "reliable", 0)
func _request_match_config() -> void:
if not multiplayer.is_server() or _last_match_config.is_empty():
return
var peer_id := multiplayer.get_remote_sender_id()
_match_config.rpc_id(
peer_id, _last_match_config["arena_path"], _last_match_config["peer_ids"],
_last_match_config["teams"], _last_match_config["spawn_indices"]
)
@rpc("any_peer", "call_remote", "unreliable_ordered", 1)
func _recv_input(bytes: PackedByteArray) -> void:
if not multiplayer.is_server():
return
var peer_id := multiplayer.get_remote_sender_id()
var decoded := NetCodec.unpack_input(bytes)
input_received.emit(peer_id, decoded)
@rpc("authority", "call_remote", "unreliable_ordered", 2)
func _snapshot(bytes: PackedByteArray) -> void:
var decoded := NetCodec.unpack_snapshot(bytes)
snapshot_received.emit(decoded)
@rpc("authority", "call_remote", "reliable", 0)
func _score_update(score: Dictionary) -> void:
score_update_received.emit(score)