Modern open-source C# .NET 10 Asheron's Call client. Faithful port of retail client behaviour to Silk.NET with a plugin API.
Find a file
Erik 46d209d053 feat(net): N2 - inbound sequence-aligned ISAAC + NAK set
Campaign N Slice N2 (docs/plans/2026-07-29-network-transport-campaign.md
S2.2) - the second fatal #260 fix: the inbound keystream now aligns to
SEQUENCE order instead of arrival order. One lost S2C datagram no longer
desyncs the inbound cipher permanently - the missing id's pre-drawn key
parks in the NAK set, later packets keep decoding, and the retransmission
decodes with the parked key.

New src/AcDream.Core.Net/Transport/InboundSequenceTracker.cs - retail's
ReceiverData inbound half, ported rule for rule:
- Sanity window: drop when seq is wrap-safe newer than
  highestIDReceived_ + 0x7FFF (SharedNet::SeqIDSanityCheck @ 0x00543A20;
  the boundary itself is accepted).
- Duplicate/late arrival (encrypted, at/below the watermark): NAK-set
  hit -> decrypt with the PARKED pre-drawn key; miss -> silent drop at
  ZERO keystream cost (SharedNet::ProcessNewSeqNum @ 0x00544690, the
  AVL::Remove branch) - the dup-word-burn and double-dispatch bugs close
  together.
- Gap walk (SharedNet::ProcessNewestSeqNum @ 0x00541930): one inbound
  ISAAC word per missing id, drawn IN SEQUENCE ORDER BEFORE the arriving
  packet's own key (landmine #4), parked beside the id
  (ReceiverData::AddNakked @ 0x00549240, idempotent; id 0 skipped per
  retail's `if (esi_1 != 0)`). Cleartext walks to seq+1 - the borrowed
  id itself gets NAKed, so the real encrypted packet at that id can
  still decode later.
- Verify-failure re-park: a sequenced encrypted checksum failure parks
  the consumed key back beside its id so the retransmission decodes
  (SharedNet::ProcessPacket @ 0x00544790 tail, AddNakked(seq, &key)).
- Inbound RejectRetransmit -> silent NAK-set abandonment; parked keys
  discarded, alignment holds because the words were already drawn
  (SharedNet::HandleEmptyAck @ 0x005448F0).
- NAK set = SortedDictionary<uint,uint> seq -> parked key; ascending
  raw-uint enumeration matches retail's AVL walk for N4's <=114-id NAK
  emission (ReceiverData::GetNaks @ 0x005490C0).

PacketCodec split (campaign S4, retail's own factoring - the key is an
optional in/out of ReceiverData::Decrypt): TryParseBorrowed is the pure
parse + checksum-summand computation with NO keystream access anywhere;
VerifyChecksum(header, headerHash, payloadHash, uint? key) compares the
additive cleartext form (null) or headerHash + (key ^ payloadHash).
TryDecodeBorrowed(datagram, IsaacRandom?) - the consume-before-compare
site that WAS the bug - is deleted; the owned TryDecode stays
(test-only). RejectRetransmit ids are now exposed on both decoders
(borrowed RejectRetransmitBytes/Count like the Request pair; owned
RejectRetransmits list); the bytes were always inside the hashed span,
so parse-hash coverage is unchanged.

WorldSession: ProcessDatagram head is now parse -> sequence-0 split
(cleartext seq-0 = handshake/control, verified additively and processed
as before; encrypted seq-0 dropped before any keystream access, like
retail's ProcessPacket) -> tracker.Admit -> VerifyChecksum with the
admission key -> failure re-park -> unchanged flag handling, N1
transport consumption, reflex ack, and fragment loop. The
RejectRetransmit flag routes to the tracker beside the N1 NAK/ack
consumption. The handshake Connect loop moved to parse +
cleartext-verify (no tracker exists before ISAAC seeding; the
ConnectRequest is cleartext seq 0). ReliableTransport now takes both
Isaacs and exposes Inbound; the session's _inboundIsaac field is
deleted. No production caller constructed the N1 ctor outside
WorldSession, so no compatibility shape was kept.

TransportStats gains InboundDupsDropped, InboundSanityDrops,
ChecksumFailures, KeysParked (unconditional, like the N1 counters).

Watermark init = 1 is an ACE adaptation, register row AD-50 (watermark
INIT only, not a mechanism change; AD-49 stays reserved for the campaign
S5 blob-layer deferral): retail zero-inits ReceiverData, but ACE never
emits S2C sequence 1 - PacketSequence starts unprimed at uint.MaxValue,
the cleartext ConnectRequest takes NextValue 0, and the first ENCRYPTED
flush re-primes CurrentValue to 1 so the first encrypted sequenced
packet is 2 (ACE NetworkSession.cs:716-717 resolving to
UIntSequence(startingValue: 1), Sequence/UIntSequence.cs:9-13,30-41).
A zero-init watermark would gap-walk the permanent id-1 hole: one
spurious NAK, the first pre-drawn word mis-assigned to id 1, and the
keystream off by one from the first encrypted packet onward. holtburger
seeds the same value (crates/holtburger-session/src/session/api.rs:30,
last_server_seq: 1), mirroring ACE's own C2S-side
lastReceivedPacketSequence = 1 (NetworkSession.cs:57). The N0 model's
dance is pinned by the clean-lifecycle conformance test: min encrypted
S2C sequence == 2, zero NAKs, zero spurious drops.

Tests (+14; Core.Net 702 -> 716): the decisive gap test (10,11,13,14 -
13 and 14 decode with fresh words while 12's key parks with
KeysParked=1/NakCount=1, the late 12 decodes with the parked key, 15
takes the next fresh word - impossible pre-N2), zero-cost duplicate
drop (shadow ISAAC position unchanged), re-park -> byte-identical
retransmission decode, the cleartext borrowed-id rule, cleartext at the
watermark (no NAK/key/watermark change), sanity boundary +0x7FFF
accepted / +0x8000 dropped wrap-safe, skip-id-0 across the 32-bit wrap
with ascending NAK enumeration, RejectRetransmit abandonment with
alignment held, warm zero-alloc Admit; plus four real-WorldSession
conformance runs against the N0 ACE double: clean lifecycle (zero NAKs
at every stage), S2C loss of one packet of a Count=2 fragment set
(later packets STILL decode - the N2 win; late byte-identical
redelivery completes the split message intact), duplicate delivery
dropped BEFORE dispatch, and the seq-0 tracker bypass.

N3/N4 handoff notes are recorded in the campaign S9 N2 row: the interim
per-packet reflex ack acks the arriving sequence even while a gap is
parked (ACE prunes the lost id from its S2C cache before N4 could NAK
it - message recovery needs N3's retail NAK-xor-ack sweep), and ACE's
RejectRetransmit consumes a fresh CLEARTEXT sequence with no keystream
word, an ACE-vs-retail wrinkle N4's design must resolve.

Gates: dotnet build green; AcDream.Core.Net.Tests 716/716;
full-solution Release 9,732 passed / 5 skipped / 0 failed; connected
world-lifecycle gate vs local ACE RESULT=PASS (zero failures, one
pre-existing expected world-edge landblock-miss warning); canonical
nine-stop connected route RESULT=PASS.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-29 13:10:20 +02:00
.github feat(render): Vulkan campaign V11 step 4 — retire GL from CI and gate scripts 2026-07-29 03:06:45 +02:00
.vscode ci: add GitHub Agentic Workflows scaffolding + daily hygiene assessment 2026-05-22 23:31:13 +02:00
docs feat(net): N2 - inbound sequence-aligned ISAAC + NAK set 2026-07-29 13:10:20 +02:00
memory docs: reconcile project state and refresh README 2026-07-27 12:53:31 +02:00
references chore(submodule): advance WB to acdream-fix-floor-rendering 2026-05-19 13:23:19 +02:00
src feat(net): N2 - inbound sequence-aligned ISAAC + NAK set 2026-07-29 13:10:20 +02:00
tests feat(net): N2 - inbound sequence-aligned ISAAC + NAK set 2026-07-29 13:10:20 +02:00
tools feat(render): Vulkan campaign V11 step 4 — retire GL from CI and gate scripts 2026-07-29 03:06:45 +02:00
.gitattributes ci: add GitHub Agentic Workflows scaffolding + daily hygiene assessment 2026-05-22 23:31:13 +02:00
.gitignore docs(render): refine #259 diagnosis; ignore artifacts/ permanently 2026-07-29 04:03:27 +02:00
.gitmodules phase(N.0): wire up WorldBuilder fork as submodule + project refs 2026-05-08 08:51:49 +02:00
AcDream.slnx feat(render): Campaign V slice V11 commit 1 - delete ImGui, Studio, and the DevTools frontend 2026-07-28 23:56:04 +02:00
AGENTS.md docs: reconcile project state and refresh README 2026-07-27 12:53:31 +02:00
analyze_flap_live.py diag(render): flap re-diagnosed as portal-flood re-clip DRIFT; physics + camera REFUTED 2026-06-08 11:21:46 +02:00
CLAUDE.md docs: point canonical state at Campaign N; record Campaign V closed 2026-07-29 10:32:41 +02:00
find_burst.py diag(render): flap re-diagnosed as portal-flood re-clip DRIFT; physics + camera REFUTED 2026-06-08 11:21:46 +02:00
launch-a6-issue98-capture.ps1 docs(research): A6.P3 #98 — comparison harness findings + neighborhood fixtures 2026-05-23 20:12:43 +02:00
launch-a6-issue98-cottage-gfxobj-dump.ps1 test(phys): A6.P3 #98 — comparison harness reproduces cottage-floor cap 2026-05-23 20:44:50 +02:00
launch-a6-issue98-polydump.ps1 docs(research): A6.P3 #98 — comparison harness findings + neighborhood fixtures 2026-05-23 20:12:43 +02:00
launch-flap-capture.ps1 diag(render): flap re-diagnosed as portal-flood re-clip DRIFT; physics + camera REFUTED 2026-06-08 11:21:46 +02:00
launch-flap-churn.ps1 diag(render): launch-flap-churn.ps1 — Phase 1 portal-churn pin capture script 2026-06-08 12:56:44 +02:00
launch-flap-verify.ps1 docs(render): FLAP settled by live-retail measurement — full retail port DECIDED (Option A) + exhaustive handoff 2026-06-08 16:19:34 +02:00
NOTICE.md chore(O-T1): create Core/Rendering/Wb directory + NOTICE.md attribution 2026-05-21 14:59:56 +02:00
README.md docs: reconcile project state and refresh README 2026-07-27 12:53:31 +02:00

acdream

A modern open-source C# / .NET 10 Asheron's Call client.

acdream ports the observable behaviour of the September 2013 retail client to Silk.NET and a modern, plugin-friendly architecture. The code is modern; the behaviour is retail.

Status: playable pre-alpha. M3, “Cast a spell,” landed on 2026-07-21 and M4, “Live in the world,” is active. The graphical client supports the connected combat, magic, movement, portal, inventory, loot, and retained-UI loops used by the current test characters. The presentation-independent GameRuntime and the Linux/Windows multi-session headless host are complete. Native Linux graphics are intentionally parked at the L1 capability checkpoint; Windows is the currently validated graphical platform.

The documentation map is the entry point for current milestones, roadmap state, architecture, issues, retail divergences, research, and durable project memory.

Technology

  • Runtime: C# and .NET 10
  • Graphics: Silk.NET, OpenGL 4.3 core, bindless textures, shader draw parameters, SSBOs, and multi-draw indirect
  • Audio: OpenAL through Silk.NET
  • Content: retail DAT files plus a machine-local, memory-mapped acdream.pak produced by AcDream.Bake
  • Networking: custom UDP, ISAAC cipher, and game-message layers compatible with ACEmulator
  • UI: retained retail gameplay UI plus opt-in ImGui developer tools
  • Automation: the same presentation-independent GameRuntime is hosted by both the graphical client and AcDream.Headless

The modern renderer is mandatory. There is no legacy renderer fallback. Startup reports an actionable error if the required OpenGL capabilities are missing.

What works

  • ACE login, character selection, world entry, chat, client commands, reconnect, and graceful logout.
  • Outdoor, building, cellar, and dungeon streaming with prepared terrain, scenery, buildings, EnvCells, collision, portal visibility, sky, fog, lighting, audio, and day/night presentation.
  • Local and observed movement, animation, jumping, selection, radar, combat stances, melee, bows, crossbows, spell projectiles, death, corpses, chests, and looting.
  • Inventory bags, stable server ordering, stack splitting, ground drops, paperdoll equipment, weapon switching, quick bars, item use, cooldowns, and giving items to NPCs.
  • Retail-style retained UI for vitals, chat, toolbar, inventory, character, attributes, skills, spellbook, components, effects, combat/spell/jump bars, radar/compass, dialogs, external containers, and assessment.
  • Complete end-of-retail spell catalog, learned and favorite spells, component preflight, connected casts, enchantments, DAT-driven projectiles and effects, recall, portal-space travel, Hidden/UnHide, and remote materialization.
  • One presentation-independent runtime owner for session, entities, objects, inventory, character state, selection, interactions, combat, magic, movement, physics, projectiles, world environment, and portal transit.
  • A no-window Windows/Linux host with deterministic bot commands/events, shared immutable content, multi-session scheduling, isolation, reconnect, resource telemetry, and tested 1/5/10/30-session ownership.
  • Plugin loading, shared command/input abstractions, retained markup panels, and permanent ImGui developer tools behind ACDREAM_DEVTOOLS=1.

Current boundaries

  • The active M4 prelude is world interaction completion. Slices 13, including assessment and its final formula/icon/layout correction, are user-accepted. Equipped-child picking and vendor browse/buy/sell are the next uncompleted slices.
  • Issue #225 retains the lifestone/particle shared-alpha visual comparison. Its connected lifetime and performance routes already pass.
  • Narrow carried behaviour debt includes issue #153 (an unstreamed far-teleport edge), issue #116 (slide feel), issue #235 (30 Hz capped/RDP jump presentation), and the live temporary-stopgap rows in the retail divergence register.
  • Native Linux graphics are deferred. L0 portability and L1 backend/capability reporting are implemented; WSLg reaches the GPU through Mesa D3D12 but does not expose mandatory GL_ARB_bindless_texture. Resume with a supported physical Linux AMD/NVIDIA driver before beginning later Slice L work.
  • Advanced vendor/trade/crafting/social surfaces and larger M4 quest, character-creation, and emote bodies remain roadmap work.

Prerequisites

  • .NET 10 SDK
  • Your own retail Asheron's Call DAT directory containing:
    • client_portal.dat
    • client_cell_1.dat
    • client_highres.dat
    • client_local_English.dat
  • A machine-local acdream.pak built from those DATs
  • A running ACE server for connected play; the examples use 127.0.0.1:9000
  • For the graphical client, a driver exposing the mandatory modern OpenGL capabilities

The project does not distribute Microsoft/Turbine DAT files or derived prepared packages.

Build and test

dotnet restore AcDream.slnx
dotnet build AcDream.slnx -c Release
dotnet test AcDream.slnx -c Release --no-build

The current baseline is a successful Release build with 8,826 passing tests and 5 intentional skips. The build currently reports 17 test-project warnings tracked by #228; production compilation has zero errors.

Prepare content

Production rendering and collision use the validated prepared package rather than decoding world meshes on the frame path:

dotnet run --project src\AcDream.Bake\AcDream.Bake.csproj -c Release -- `
  --dat-dir "C:\Games\Asheron's Call" `
  --out "C:\Games\Asheron's Call\acdream.pak"

A complete package is approximately 30 GB. It is machine-local and must not be committed. ACDREAM_PAK_PATH overrides the default <DAT directory>\acdream.pak.

Run the graphical client

$env:ACDREAM_DAT_DIR   = "C:\Games\Asheron's Call"
$env:ACDREAM_PAK_PATH  = "C:\Games\Asheron's Call\acdream.pak"
$env:ACDREAM_LIVE      = "1"
$env:ACDREAM_TEST_HOST = "127.0.0.1"
$env:ACDREAM_TEST_PORT = "9000"
$env:ACDREAM_TEST_USER = "testaccount"
$env:ACDREAM_TEST_PASS = "testpassword"
$env:ACDREAM_RETAIL_UI = "1"

dotnet run --project src\AcDream.App\AcDream.App.csproj -c Release

The DAT directory can instead be supplied as the first positional argument:

dotnet run --project src\AcDream.App\AcDream.App.csproj -c Release -- `
  "C:\Games\Asheron's Call"

Run a headless session

AcDream.Headless loads no App, UI, OpenGL, native-window, or audio assembly. Create a version-1 configuration such as bot.json:

{
  "version": 1,
  "process": {
    "content": {
      "datDirectory": "/opt/ac",
      "preparedAssetPath": "/opt/ac/acdream.pak"
    }
  },
  "sessions": [
    {
      "id": "bot-1",
      "endpoint": { "host": "127.0.0.1", "port": 9000 },
      "account": "testaccount",
      "character": { "index": 0 },
      "policy": { "id": "idle" },
      "credential": {
        "provider": "environment",
        "reference": "ACDREAM_BOT_PASSWORD"
      }
    }
  ]
}

Then validate and run it:

export ACDREAM_BOT_PASSWORD='testpassword'
dotnet run --project src/AcDream.Headless/AcDream.Headless.csproj -c Release -- \
  validate --config bot.json
dotnet run --project src/AcDream.Headless/AcDream.Headless.csproj -c Release -- \
  run --config bot.json

For a single local session, run also accepts --user <account> --password <password>. Add uniquely identified session entries and credential references for a multi-session process. Available built-in policies are idle, lifecycle-smoke, observer-movement, and portal-route-smoke.

Useful startup options

Variable Effect
ACDREAM_DAT_DIR Retail DAT directory
ACDREAM_PAK_PATH Prepared package path; defaults to <DAT dir>/acdream.pak
ACDREAM_LIVE=1 Enable connected mode
ACDREAM_TEST_HOST / ACDREAM_TEST_PORT ACE endpoint
ACDREAM_TEST_USER / ACDREAM_TEST_PASS Graphical-client credentials
ACDREAM_RETAIL_UI=1 Enable the retained retail gameplay UI
ACDREAM_DEVTOOLS=1 Enable ImGui developer tools
ACDREAM_NO_AUDIO=1 Suppress OpenAL initialization
ACDREAM_UNCAPPED_RENDER=1 Disable normal frame pacing for diagnostics
ACDREAM_DISPLAY_PROTOCOL=auto|x11|wayland Select the Linux GLFW backend
ACDREAM_DAY_GROUP=N Force a day-group index for weather/lighting comparisons
ACDREAM_STREAM_RADIUS=N Legacy override over configured streaming radii
ACDREAM_DUMP_SKY=1 Dump sky interpolation and draw diagnostics
ACDREAM_DUMP_MOTION=1 Dump inbound movement and motion-cycle decisions

Additional diagnostic and budget controls are documented beside their typed owners and in the linked research plans; they are not stable user settings.

Repository layout

src/
  AcDream.Runtime/              presentation-independent GameRuntime
  AcDream.App/                  graphical host, retained UI, renderer, audio
  AcDream.Headless/             Windows/Linux no-window multi-session host
  AcDream.Core/                 retail gameplay, movement, physics, world logic
  AcDream.Core.Net/             UDP, ISAAC, protocol and message routing
  AcDream.Content/              GL-free DAT and prepared-package content
  AcDream.Bake/                 offline acdream.pak builder
  AcDream.Cli/                  offline DAT inspector
  AcDream.UI.Abstractions/      shared UI/input models and contracts
  AcDream.UI.ImGui/             developer-tool presentation
  AcDream.Plugin.Abstractions/  BCL-only plugin contracts
  AcDream.Plugins.Smoke/        example plugin

tests/
  AcDream.*.Tests/              layer-matched xUnit projects

docs/
  README.md                     documentation authority and current map
  architecture/                ownership, structure, divergence, WB inventory
  plans/                       milestone, roadmap, and execution plans
  research/                    retail pseudocode, traces, fixtures, evidence
  audit/                       completion and conformance audits

memory/                        durable engineering references
references/                    gitignored external reference repositories

Development workflow

All AC-specific behaviour starts from the named retail oracle in docs/research/named-retail/:

  1. Search the named retail pseudo-C and headers by class::method.
  2. Use the older Ghidra chunks only when the named oracle is insufficient.
  3. Cross-reference ACE and the relevant client/viewer implementation.
  4. Record readable pseudocode and exact constants/order.
  5. Port the retail mechanism into the correct modern owner.
  6. Add conformance, lifecycle, and failure-boundary tests.
  7. Run the automated gate and the appropriate connected or visual gate.
  8. Update architecture, roadmap, divergences, and durable memory with the same change.

Guessing at AC-specific algorithms is forbidden. See AGENTS.md, CLAUDE.md, and the architecture guide for the full rules.

Reference projects

  • ACE / ACEmulator: authoritative server and protocol behaviour
  • ACViewer: character appearance and DAT presentation cross-check
  • WorldBuilder: extracted Silk.NET DAT/rendering foundation
  • Chorizite.ACProtocol: clean-room protocol reference
  • holtburger: broad non-retail client behaviour reference
  • AC2D: terrain and movement-packet cross-checks

The retail binary/decomp remains the behavioural oracle when references disagree.

Licence and game assets

The acdream source has not yet been assigned a top-level licence and is not ready for public redistribution. External reference code retains its own licence.

Asheron's Call DAT files, art, names, and other game assets remain the property of Microsoft/Turbine. This repository does not distribute them; users must supply their own retail installation.