Made the multiplayer core actually work (it had never run a real sim):
- project.godot: physics pinned to 30 Hz -- the shared sim/snapshot/prediction rate.
- server.gd: loads the world's level (real ground + collision), spawns a
server Player per peer at the level's PlayerSpawn, broadcasts a full
snapshot every physics frame with each peer's state AND last_seq (the last
input seq applied for that peer). Accepts `--port/--world/--status-file`
args (status file = player count for a future idle reaper); defaults keep
`godot res://scenes/server.tscn` working standalone.
- player_spawner.gd (server Player): rewrote -- drains its whole input queue
each physics frame in seq order, integrates gravity/walk/jump with the
shared constants, move_and_slide(), tracks last_applied_seq. No more no-op
process_server_input().
- network_client.gd: rewrote reconciliation -- drops inputs the server has
acked (last_seq), re-simulates the still-in-flight ones from the
authoritative state, snaps only on real drift. Exposes get_remote_states()
(peer_id -> latest snapshot state) for the game to render other players.
predict_and_send() now also sends body yaw.
- proxies trimmed to the RPC set the rewrite actually uses.
- scripts/mp_test_client.gd + run_multiplayer_2p_test.sh: two real client
processes vs one real server -- client A sees client B and its own
movement round-trips. PASS.
- run_checkpoint_tests.py: also run the 2p shell test.
smoke_test_network_client 4/4, player 15/15, avatar_in_world 10/10, all green.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015jtxAiu5dAW4WxCNdGkrkJ
Real client-side networking for the player controller, verified with a
genuine two-process integration test (an actual dedicated server process
+ a real ENet-connected client), per docs/architecture/networking.md §5.
scripts/network_client.gd: NetworkClient -- predicts movement locally on
input (same movement constants as scripts/player_spawner.gd), sends input
to the server via RPC, and reconciles against the server's authoritative
snapshots when they diverge beyond a threshold.
scripts/network_receiver_proxy.gd + network_player_proxy.gd: the RPC
plumbing that makes this actually route correctly, which took real
debugging to get right:
- Godot's rpc_id() resolves the receiving node by matching the sending
node's NodePath between peers. scripts/server.gd is the SceneTree root
node "Server" when the dedicated server runs, and spawns each player as
"Player_<peer_id>" under itself -- so the client needs its own node
tree at those same paths purely for RPC routing.
- Godot also enforces an RPC "node checksum": both peers must declare the
*same set* of @rpc methods at a matching path, or every RPC at that
path fails, not just a genuinely missing one. Every @rpc method on
scripts/server.gd's root and scripts/player_spawner.gd had to be
mirrored here (mostly as no-op stubs), not just the ones this class
actually calls.
Known, explicitly-scoped simplification (stated in the code, not hidden):
scripts/server.gd's snapshot doesn't currently echo back a per-peer "last
input seq processed", so reconciliation corrects against the most recent
prediction rather than true tick-exact rollback-and-replay
(networking.md §5.2 step 4). A real follow-up once the server echoes
that ack, not faked here.
Verified: real two-process test (godot --headless --path . scenes/
server.tscn as an actual persistent process, a second process running
scripts/smoke_test_network_client.gd against it over real ENet) --
4/4 passing: connects, predicts locally before any server round trip,
sends real input, and a deliberately-desynced position (moved 9999 units
away) gets corrected by the very next real snapshot. Full existing
client suite (10 suites) + 61 backend pytest still passing.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M6rUEynmv2QmweocAQYARN
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claude-checkpoint-tooling
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