Modern open-source C# .NET 10 Asheron's Call client. Faithful port of retail client behaviour to Silk.NET with a plugin API.
f4f4143ac0
Replaces the mesh-AABB approximation with retail's actual selection
mechanism. The user observed the indicator was too small and didn't
scale with the object the way retail does — root cause was using the
wrong source data.
Retail trace (decomp anchors in named-retail/acclient_2013_pseudo_c.txt):
- VividTargetIndicator::Draw at 0x004f6c30 is registered as the
SmartBox targetting callback (0x004f6df6).
- SmartBox::DoTargettingChecks at 0x00453bb4 calls
SmartBox::GetObjectBoundingBox (0x00452e20) to compute the rect.
- GetObjectBoundingBox uses CPhysicsObj::GetSelectionSphere
(0x0050ea40) → CPartArray::GetSelectionSphere (0x00518b80) which
reads setup->selection_sphere from the DAT, applies part-array
scale (component-wise on center, Z-scale on radius), then calls
Render::GetViewerBBox (0x0054b400) to project the sphere as a
screen-space camera-aligned BBox.
- VividTargetIndicator::OnDraw at 0x004f62b0 inflates that rect by
one triangle width/height on every side before drawing (eax_21 /
eax_23 in 0x004f6a0b–0x004f6a99), so the corner triangles sit
outside the projected sphere with a small gap.
Implementation:
- GameWindow.TryGetEntitySelectionSphere reads setup.SelectionSphere
from the DAT (Setup type already exposes Origin + Radius),
applies entity scale, rotates center via entity orientation, and
produces a world-space sphere.
- TargetIndicatorPanel.TryComputeScreenRectFromSphere projects the
sphere center via the view-projection matrix and computes
screenRadius = worldRadius * projection.M22 * viewport.Y /
(2 * clip.W). M22 = cot(fovY/2) for a standard right-handed
perspective. Mathematically equivalent to retail's
Render::GetViewerBBox followed by 2-corner xformPointInternal,
faster (no double projection).
- TargetInfo carries WorldSphereCenter + WorldSphereRadius (replaces
the previous WorldAabbMin/Max). Fallback to per-type height
heuristic still in place if Setup has no baked selection_sphere
(rare; Radius <= 1e-4f short-circuits).
- Inflate by TriangleSize on every side matches retail's eax_21 +
eax_23 offsets exactly.
- Triangle right-angle apex flipped to point INWARD toward the
target (per user feedback) — apex at corner + (±t, ±t),
hypotenuse along the outer diagonal of the corner.
- TriangleSize 10 → 14 → 8 (retail sprite is small).
Also fixes a parser bug in CreateObject.cs introduced in
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| docs | ||
| memory | ||
| references | ||
| src | ||
| tests | ||
| tools | ||
| .gitignore | ||
| .gitmodules | ||
| AcDream.slnx | ||
| CLAUDE.md | ||
| README.md | ||
acdream
A modern open-source C# / .NET 10 Asheron's Call client.
Faithful port of the retail client's behaviour to Silk.NET with a modern, plugin-friendly architecture. The code is modern; the behaviour is retail.
Status: playable pre-alpha. You can log in to an ACE server, walk and run through Dereth, see other players animate correctly, watch the day-night cycle, hear ambient audio, and take weapons out. Many systems are still stubbed or in-progress — see roadmap.
Stack
- Language: C# .NET 10
- Graphics: Silk.NET (OpenGL 4.3)
- Audio: OpenAL via Silk.NET
- Dat parsing: Chorizite.DatReaderWriter
- Networking: Custom UDP + ISAAC cipher + game-message layer, wire-compatible with ACEmulator server
What works
- Connecting to a local ACEmulator (ACE) server on
127.0.0.1:9000 - Character selection and login
- Rendering Dereth terrain with retail-correct texture blending, per-vertex lighting, and road overlays
- Static scenery (buildings, trees, scenery objects) via EnvCell walker
- Animated characters (own + remote) with walk / run / strafe / jump / turn / attack motions sourced from the retail motion tables
- Network sync with remote players — you can watch other characters animate correctly, including speeds and directional motion
- Day-night cycle driven from the retail Region dat (0x13000000) — correct DayGroup picking via the retail LCG, correct keyframe interpolation, correct per-keyframe sky-object replace
- Weather (rain/snow particles synced from the server via the retail DayGroup name)
- Sky dome, stars, moon, clouds, sun — each rendered from the retail Region's SkyObjects with texture scrolling and alpha fade
- Plugin host with live event replay-on-subscribe
What's stubbed or in-progress
- Indoor transitions (building interiors) — disabled, Phase B.3 pending
- Combat — animation works, damage math not wired
- Lightning visual — the retail PhysicsScript-driven flash is researched
but not wired (see
docs/research/2026-04-23-lightning-real.md) - TimeSync drift — we only sync calendar on login, not periodically, so acdream's in-game clock gradually drifts from retail's
- Landscape draw distance — currently
ACDREAM_STREAM_RADIUS=2(~400m) vs retail's several kilometres
See docs/plans/2026-04-11-roadmap.md for the ordered phase list.
See docs/ISSUES.md for the rolling list of known bugs + small deferred
features (tactical, bug-level; the roadmap is strategic, phase-level).
Building + running
Requires:
- .NET 10 SDK
- A retail Asheron's Call dat directory (Turbine/Microsoft property —
supply your own). Contains
client_portal.dat,client_cell_1.dat,client_highres.dat,client_local_English.dat. - A running ACE (ACEmulator) server on
127.0.0.1:9000(or override via env var)
Launch (PowerShell on Windows — bash has trouble with the apostrophe in "Asheron's Call"):
$env:ACDREAM_DAT_DIR = "$env:USERPROFILE\Documents\Asheron's Call"
$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"
dotnet run --project src\AcDream.App\AcDream.App.csproj -c Debug
Offline CLI dat inspector (no server needed):
dotnet run --project src/AcDream.Cli -- "C:\path\to\Asheron's Call"
Diagnostic env vars
| Variable | Effect |
|---|---|
ACDREAM_DUMP_SKY=1 |
Per-second dump of the interpolated SkyKeyframe values + per-SkyObject draw info + texture alpha histograms |
ACDREAM_DUMP_MOTION=1 |
Dump every inbound UpdateMotion + resulting SetCycle |
ACDREAM_STREAM_RADIUS=N |
Tune landblock visible-window radius (default 2 = 5×5) |
ACDREAM_NO_AUDIO=1 |
Suppress OpenAL init |
ACDREAM_DAY_GROUP=N |
Force a specific DayGroup index for A/B-testing weather presets |
ACDREAM_RUN_SKILL=N / ACDREAM_JUMP_SKILL=N |
Client-side run/jump skill (default 200) |
Layout
src/
AcDream.App/ rendering + audio + main loop (Silk.NET)
AcDream.Core/ game state, meshing, physics, sky, weather, lighting
AcDream.Core.Net/ UDP + ISAAC + game-message layer
AcDream.Cli/ offline dat-inspector console app
AcDream.Plugin.Abstractions/ plugin host interfaces
AcDream.Plugins.Smoke/ example plugin
tests/
AcDream.Core.Tests/ xUnit tests (742 passing)
AcDream.Core.Net.Tests/ network-layer tests
tools/
RetailTimeProbe/ Win32 P/Invoke ReadProcessMemory probe of
the live retail acclient.exe — dumps
TimeOfDay + sky-lighting globals so we
can compare against acdream's state
SkyObjectInspect/ dat-inspector for Region sky objects
references/ vendored read-only reference code — ACE,
ACViewer, WorldBuilder, holtburger,
AC2D, Chorizite, DatReaderWriter.
Gitignored.
docs/
architecture/ single-source-of-truth architecture doc
plans/ phase roadmaps + per-phase specs
research/ decompile-derived research, per-phase
findings, deep-dive agent reports
audit/ phase-completion audits
Development workflow
All AC-specific behaviour is ported from the decompiled retail client
(docs/research/decompiled/). The workflow is:
- Decompile first. Find the matching function in the decompiled client.
- Cross-reference. Check against ACE's C# port and ACViewer / WorldBuilder.
- Write pseudocode. Translate C to readable pseudocode first.
- Port faithfully. Translate line-by-line, preserving variable names and control flow.
- Conformance test. Add tests using golden values from retail.
- Integrate surgically. Minimise churn in the surrounding pipeline.
Guessing at AC-specific algorithms is explicitly forbidden — see
CLAUDE.md for the full workflow rationale and the list of failure
modes we've paid for in the past.
Reference repos
We cross-reference five external projects for every retail behaviour:
- ACE (ACEmulator) — authoritative server-side protocol
- ACViewer — MonoGame dat viewer; good for character appearance
- WorldBuilder — Silk.NET dat editor; matches our stack
- Chorizite.ACProtocol — clean-room C# protocol library
- holtburger — most complete non-retail client; Rust TUI, full client-side behaviour
- AC2D — C++ AC-client emulator; has the real terrain split formula and 0xF61C movement packet format
See CLAUDE.md for which reference is authoritative for which domain.
Licence
Not yet chosen. All external reference code is vendored under its own
licence; see references/*/LICENSE. The acdream source code itself is
unreleased — not yet distributed to the public. Once the licence
choice is made it will go in a top-level LICENSE file.
The AC dat files and the game's intellectual property remain the property of Microsoft / Turbine. This project does not distribute any of those files or assets — you must supply your own retail install.