Decodes the CreateObject (0xF745) game message body far enough to hand
an entity off to acdream's existing IGameState/MeshRenderer pipeline.
Ported from ACE's WorldObject_Networking.cs (SerializeCreateObject,
SerializeModelData, SerializePhysicsData) and Position.cs.
Scope: the parser extracts exactly three fields —
- GUID (u32 right after the opcode)
- ServerPosition (landblockId + XYZ + rotation quaternion), if the
Position bit is set in the PhysicsDescriptionFlag
- SetupTableId (setup dat id for the visual mesh chain), if the
CSetup bit is set
Everything else in a CreateObject body (weenie header, object description,
motion tables, palettes, texture overrides, animation frames, velocity,
acceleration, omega, scale, friction, elasticity, translucency,
default scripts, sequence timestamps, ...) is consumed-or-skipped with
just enough bytes to advance past the correct flag-gated sections.
The parser stops at the end of PhysicsData — we don't need weenie-header
fields for rendering placement.
Components parsed in order (all from ACE's serialize routines):
1. Opcode u32 (must be 0xF745)
2. u32 GUID
3. ModelData header (byte 0x11 marker, byte subPaletteCount,
byte textureChangeCount, byte animPartChangeCount), followed by
PackedDword palette/subPalette fields, texture change records,
anim part change records, aligned to 4 bytes at end
4. u32 PhysicsDescriptionFlag
5. u32 PhysicsState (skipped)
6. Conditional Movement/AnimationFrame section
7. Conditional Position section (LandblockId, X, Y, Z, RW, RX, RY, RZ)
8. Conditional MTable/STable/PeTable u32 ids (all skipped)
9. Conditional CSetup u32 (extracted as SetupTableId)
The PackedDword reader is a new helper: AC's variable-width uint format
where values ≤ 32767 encode as a u16, larger values use a marker bit in
the top of the first u16 and a continuation u16. Ported from
Extensions.WritePackedDword.
LIVE RUN AGAINST THE ACE SERVER (test account, Holtburg):
step 4: CharacterList received account=testaccount count=2
character: id=0x5000000A name=+Acdream
character: id=0x50000008 name=+Wdw
sent CharacterEnterWorldRequest
step 6: CharacterEnterWorldServerReady received
sent CharacterEnterWorld(guid=0x5000000A)
step 8 summary: 83 GameMessages assembled, 68 CreateObject,
68 parsed, 52 w/position, 68 w/setup
First 10 parsed CreateObjects:
guid=0x5000000A lb=0xA9B40021 xyz=(104.89,15.05,94.01) setup=0x02000001
guid=0x80000600 no position setup=0x02000181
guid=0x800005FF no position setup=0x02000B77
guid=0x80000603 no position setup=0x02000176
guid=0x80000604 no position setup=0x02000D5C
guid=0x80000694 no position setup=0x020005FF
guid=0x80000697 no position setup=0x02000921
guid=0x80000601 no position setup=0x02000179
guid=0x80000605 no position setup=0x02000155
guid=0x80000695 no position setup=0x020005FF
The first line is +Acdream himself — GUID matches what we picked from
CharacterList, landblock 0xA9B4 is Holtburg (the area we already render),
setup 0x02000001 is the default humanoid player mesh. The other 67 are
NPCs/weenies/scenery-weenies in the same area; the 16 without positions
are inventory items whose position is inherited from the parent.
ALL 68 CreateObjects parsed cleanly — no short reads, no format errors.
Phase 4.7d proves byte-level compatibility with ACE's outbound network
serialization format. The remaining Phase 4 work (WorldSession type +
GameWindow wiring) is glue code above a codec that now speaks the real
AC wire format.
Tests: 77 core + 83 net (+1 live test) = 161 passing, all green.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Drives the full post-handshake flow on a live ACE server. After the
3-way handshake completes, acdream:
1. Reassembles CharacterList and parses out every character on the
account (tested against testaccount which has two: +Acdream and
+Wdw). Full field decode: GUIDs, names, delete-delta, slotCount,
accountName, turbine chat, ToD flag.
2. Picks the first character and builds a single-fragment
CharacterEnterWorldRequest (opcode 0xF7C8, empty body beyond opcode)
on the UIQueue, wraps it with EncryptedChecksum + BlobFragments,
consumes one outbound ISAAC keystream word, and sends.
3. Waits for CharacterEnterWorldServerReady (opcode 0xF7DF) to confirm
the server accepted our encrypted outbound packet.
4. Builds CharacterEnterWorld (opcode 0xF657, body = u32 guid +
String16L accountName) and sends as a second fragment with
fragment_sequence 2, packet sequence 3.
5. Drains 10 seconds of post-login traffic: 101 GameMessages assembled,
68 of which are CreateObject (0xF745) — the entities around
+Acdream spawning into our session. Also saw DeleteObject (0xF746),
ObjectDescription (0xF74C), SetState (0xF755), GameEvent (0xF7B0),
LoginCharacterSet (0xF7E0), and a 0x02CD smaller opcode.
This is the Phase 4.7 win: acdream is authenticated, connected,
character-selected, logged in, and actively receiving the world state
stream, all with ZERO protocol errors. Every byte of every packet we
sent to the server was correct — the first bit wrong in our outbound
ISAAC math would have produced silent disconnect instead of 101
successful replies.
Added to AcDream.Core.Net:
- Messages/CharacterList.cs: full parser for opcode 0xF658, ported
from ACE's GameMessageCharacterList writer. Returns structured
record with Characters[], SlotCount, AccountName, UseTurbineChat,
HasThroneOfDestiny. Tested offline with hand-assembled bodies
matching ACE's writer format.
- Messages/CharacterEnterWorld.cs: outbound builders for
CharacterEnterWorldRequest (0xF7C8, opcode-only) and
CharacterEnterWorld (0xF657, opcode + guid + String16L account).
- Messages/GameMessageFragment.cs: helper to wrap a GameMessage body
in a single MessageFragment with correct Id/Count/Index/Queue and
Sequence. Also a Serialize helper to turn a MessageFragment into
packet-body bytes for PacketCodec.Encode. Throws on oversize
(>448 byte) messages; multi-fragment outbound split is TBD.
- GameMessageGroup enum mirroring ACE byte-for-byte (UIQueue = 0x09
is the one we use for enter-world).
Fixed: FragmentAssembler was keying on MessageFragmentHeader.Id, but
ACE's outbound fragment Id is ALWAYS the constant 0x80000000 — the
unique-per-message key is Sequence, matching how ACE's own
NetworkSession.HandleFragment keys its partialFragments dict. Our
live tests happened to work before because every GameMessage we'd
seen was single-fragment (hitting the Count==1 shortcut), but
multi-fragment CreateObject bodies would have silently mixed. Fixed
now and all 7 FragmentAssembler tests still pass with the Sequence-key.
Tests: 9 new offline (4 CharacterList, 2 CharacterEnterWorld, 3
GameMessageFragment), 1 new live (gated by ACDREAM_LIVE=1). Total
77 core + 83 net = 160 passing.
LIVE RUN OUTPUT:
step 4: CharacterList received account=testaccount count=2
character: id=0x5000000A name=+Acdream
character: id=0x50000008 name=+Wdw
choosing character: 0x5000000A +Acdream
sent CharacterEnterWorldRequest: packet.seq=2 frag.seq=1 bytes=40
step 6: CharacterEnterWorldServerReady received
sent CharacterEnterWorld(guid=0x5000000A): packet.seq=3 frag.seq=2 bytes=60
step 8 summary: 101 GameMessages assembled, 68 CreateObject
unique opcodes seen: 0xF7B0, 0xF7E0, 0xF746, 0xF745, 0x02CD,
0xF755, 0xF74C
Phase 4.7 next: start decoding CreateObject bodies to extract GUID +
world position + setup/GfxObj id, so these entities can flow into
IGameState and render in the acdream game window. The foundry statue
is waiting in one of those 68 spawns.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Reassembles the fragments arriving from the live handshake into full
game message bodies, reads the opcode from the first 4 bytes, and
identifies them by name. On the live wire we now see exactly the
sequence ACE sends right after HandleConnectResponse:
GameMessage assembled: opcode=0xF7E5 (DDDInterrogation), body=28 bytes
GameMessage assembled: opcode=0xF658 (CharacterList), body=80 bytes
GameMessage assembled: opcode=0xF7E1 (ServerName), body=20 bytes
summary: 5 packets received, 5 decoded OK, 0 checksum failures,
3 GameMessages assembled
Every layer of the net stack is now proven live:
* NetClient send/receive on both ports 9000 and 9001
* PacketCodec.Encode building LoginRequest + ConnectResponse with
correct unencrypted CRC
* IsaacRandom byte-compatible with ACE's ISAAC (3 EncryptedChecksum
packets decoded, zero mismatches)
* PacketHeaderOptional parsing ConnectRequest, TimeSync, AckSequence
* MessageFragment.TryParse walking a body tail of back-to-back
fragments (the 152-byte packet had TWO messages: CharacterList
and ServerName packed into one datagram)
* FragmentAssembler reassembling by index
The CharacterList body has our test character +Acdream inside it but
we're not decoding its fields yet — that's Phase 4.7 where we actually
pick a character and send CharacterLogin to enter the game world.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This is the Phase 4 protocol-compatibility proof. acdream's codec now
completes the full AC UDP handshake against a live ACE server and
successfully decodes three consecutive EncryptedChecksum game packets
— which means every layer of the codec is byte-compatible with ACE.
Changes:
- NetClient: added Send(IPEndPoint, ReadOnlySpan<byte>) overload so
one socket can talk to ACE's two listener ports (9000 for
LoginRequest, 9001 for ConnectResponse and all subsequent traffic)
- LiveHandshakeTests.Live_FullThreeWayHandshake_ReachesConnectedState:
drives the full 3-leg handshake end-to-end. Protocol details that
I got wrong on the first attempt and fixed after reading
references/holtburger/crates/holtburger-session/src/session/auth.rs:
* ConnectResponse header.Sequence = 1 (LoginRequest is seq 0)
* ConnectResponse header.Id = 0 (NOT the clientId from
ConnectRequest; that field is ACE's internal session index,
separate from the packet header Id)
* 200ms Thread.Sleep before sending ConnectResponse — holtburger
calls this ACE_HANDSHAKE_RACE_DELAY_MS, empirically determined
to avoid a server-side race where ACE is still finalizing the
session when our ConnectResponse arrives
* ConnectResponse goes to port 9001, not 9000 (ACE's second
ConnectionListener, see Network/Managers/SocketManager.cs)
LIVE RUN OUTPUT:
[live] step 1: sending 84-byte LoginRequest to 127.0.0.1:9000
[live] step 2: got 52-byte datagram from 127.0.0.1:9000,
flags=ConnectRequest
ConnectRequest cookie=0x458ABEE950D18BEE clientId=0x00000000
[live] step 3: sleeping 200ms then sending 28-byte ConnectResponse
to 127.0.0.1:9001
ISAAC seeds primed
[live] step 4: got 28-byte datagram from :9001,
flags=EncryptedChecksum,TimeSync, seq=2 OK
[live] step 4: got 64-byte datagram from :9001,
flags=EncryptedChecksum,BlobFragments, seq=3 OK
[live] step 4: got 152-byte datagram from :9001,
flags=EncryptedChecksum,BlobFragments, seq=4 OK
[live] step 4: got 24-byte datagram from :9001,
flags=AckSequence, seq=4 OK
[live] step 4: got 24-byte datagram from :9001,
flags=AckSequence, seq=4 OK
[live] step 4 summary: 5 packets received, 5 decoded OK,
0 checksum failures
What each "OK" proves, reading left to right:
* TimeSync (seq=2): our IsaacRandom is byte-compatible with ACE's
ISAAC.cs — if a single bit were wrong in any state register the
checksum key would mismatch and decode would fail. Our inbound
ISAAC consumed one word for this packet.
* BlobFragments (seq=3, 64 bytes): header hash + fragment hash +
ISAAC key recipe all check out. These fragments contain the start
of GameMessageCharacterList / ServerName / DDDInterrogation game
messages ACE enqueues right after HandleConnectResponse. We don't
parse game message bodies yet (Phase 4.7) but the fragments are
fully retrievable from Packet.Fragments.
* BlobFragments (seq=4, 152 bytes): continuation of the same game
messages; our sequential ISAAC consumption handled two back-to-back
encrypted packets correctly.
* AckSequence (seq=4): unencrypted mixed with encrypted in the same
stream — our codec handles both paths in one session.
Everything in AcDream.Core.Net is now proven byte-compatible with a
retail AC server at the protocol level. The remaining Phase 4 work
(4.6f, 4.7) is above the codec: parsing game message opcodes out of
the fragment payloads and routing CreateObject into IGameState so
acdream can show the foundry statue and the +Acdream character.
Test counts: 77 core + 73 net (+1 new live test) = 150 passing.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Reaches the first major milestone of Phase 4: acdream's codec is proven
byte-compatible with a live ACE server. LiveHandshakeTests drives a real
UDP exchange against 127.0.0.1:9000 and successfully negotiates the
first half of the connect handshake.
Added:
- Packets/PacketHeaderOptional.cs: new ConnectRequest flag branch.
ACE's AGPL parser doesn't decode ConnectRequest (server only sends
it) so this is new client-side code. Exposes ConnectRequestServerTime,
Cookie, ClientId, ServerSeed, ClientSeed — the values we need to
seed our two ISAAC instances and echo the cookie back in a
ConnectResponse.
- NetClient.cs: minimum-viable UDP transport, a thin UdpClient wrapper
with synchronous Send and timeout-based Receive. No background thread
or retransmit window yet — good enough for handshake bring-up and
the offline state-machine tests.
- LiveHandshakeTests.cs: gated behind ACDREAM_LIVE=1 environment
variable so CI without a server doesn't fail. Reads credentials
from ACDREAM_TEST_USER / ACDREAM_TEST_PASS (never logged or
committed), builds a LoginRequest datagram via our codec, sends
it to localhost:9000, waits for up to 5s for a response, and
asserts we receive a ConnectRequest with non-zero cookie, clientId,
and both ISAAC seeds.
Tests (5 new, 77 total in net project, 154 across both projects):
- ConnectRequestTests: two offline tests exercising the new
PacketHeaderOptional branch via synthetic datagrams. One verifies
every field round-trips through Encode + TryDecode, one feeds the
extracted 32-bit seeds into IsaacRandom to prove they work as
keystream seeds.
- NetClientTests: 2 offline tests — loopback SendReceive round-trip
between two NetClient instances (proves UDP pump is alive without
needing any server), and Receive-with-timeout returning null
cleanly when no datagram arrives.
- LiveHandshakeTests: 1 live integration test (early-exits when
ACDREAM_LIVE env var not set, so it passes trivially in CI).
LIVE RUN OUTPUT (against user's localhost ACE server):
[live] sending 84-byte LoginRequest to 127.0.0.1:9000 (user.len=11, pass.len=12)
[live] received 52-byte datagram from 127.0.0.1:9000
[live] decode result: None, flags: ConnectRequest
[live] ConnectRequest decoded: serverTime=290029541.121 cookie=0xAC45998D06754133
clientId=0x00000001 serverSeed=0x4CC09763 clientSeed=0x5C3DE13E
Meaning: 84-byte LoginRequest went out, 52-byte ConnectRequest came
back, codec.TryDecode returned None error, every field parsed to a
sensible value. This proves byte-compatibility of both directions at
the protocol layer, ISAAC seed extraction path, Hash32 checksum on
both encode and decode, and the whole String16L/String32L/bodyLength
layout of LoginRequest against the real server parser.
Next step: send ConnectResponse echoing the cookie so the server
promotes us to "connected" and starts streaming CharacterList +
CreateObject messages (those will use EncryptedChecksum, which is
where our ISAAC implementation gets its ultimate test).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Erik