#331 reported that `PhysicsEngine.ResolveWithTransition` refuses ALL uphill
motion whenever a `body:` is supplied. It does not. It refuses a step whose
sub-step offset is exactly anti-parallel to a live sliding normal — the
#137-family absorb this project already recorded as retail-faithful.
Measured on the same fixture, same gradient, same body, varying only the
heading relative to the slope gradient:
(0, -0.1, 0) cross-slope 0 -> zero movement, latched
(0.0001,-0.1, 0) cross-slope 0.0001 m -> zero movement, latched
(0.001, -0.1, 0) cross-slope 0.001 m -> climbs 0.176 m in 5 ticks
(0.01, -0.1, 0) cross-slope 0.01 m -> climbs 0.176 m in 5 ticks
The threshold is retail's own F_EPSILON small-offset abort (0.0002 m): about
0.11 degrees off the exact gradient at a 0.1 m step. `RemoteRampHarness`
builds a ramp whose gradient is exactly along Y and the original probe pushed
exactly along -Y, so it hit the measure-zero case with probability 1.
The latch itself is production-real in mechanism — a pure gravity fall under
the production RuntimeRemotePhysicsUpdater, with no fixture settle seam
involved, lands leaving Contact|OnWalkable|Sliding with slidingNormal (0,1,0)
— but every link is faithful to retail, verified in the PDB-paired binary
rather than Binary Ninja (BN typed find_transitional_position `void` and
dropped the load-bearing return value):
validate_walkable sets collision_normal from the terrain plane when
OBJECTINFO CONTACT is clear 0x0050d251 / 0x0050d261 / 0x0050d26c
validate_transition converts it unconditionally 0x0050ac19-0x0050ac30
set_sliding_normal zeroes Z AND re-normalizes 0x0050a060
SetPositionInternal persists SLIDING_TS 0x005154c2 / 0x005154e1
get_object_info re-seeds it next frame 0x00511d44 / 0x00511d4f
find_transitional_position returns
`i != 0 && state == OK` on the step-0 abort 0x0050c0ed -> 0x0050c089
ACE agrees (Transition.cs:1027, CollisionInfo.cs:58). No production code
changed; no divergence introduced, so no register row.
What lands is the coverage whose absence made this invisible — nothing in the
suite asserted that a body-bearing mover makes uphill progress on a walkable
slope, and the test that found #331 passed vacuously because the body never
moved:
RuntimeRemoteUphillProgressTests.ARemoteWithABodyClimbsAWalkableSlopeAndKeepsItsFeetOnIt
per-tick climb + surface tracking under a realistic off-gradient heading.
SAB-A1 AdjustOffset -> Vector3.Zero reddens at tick 1
SAB-A2 fixture gradient -> 0 (flat) reddens at tick 1
RuntimeRemoteUphillProgressTests.AnExactlyUpSlopeOffsetIsAbsorbedByThePersistedSlidingNormal
characterization pin for the absorb, with the retail anchors inline.
SAB-B1 delete the get_object_info sliding seed reddens (climbs to 57.7544)
SAB-A1 reddens
SAB-A2 reddens
NON-discriminating, measured and documented: making the final tick
exactly up-slope leaves it green — by then the latch is already cleared.
RemoteRampHarness gains a warning block naming the axis-alignment trap so the
next vacuous uphill assertion is caught at authoring time.
Suite re-measured from a full clean (43 bin/obj removed): 11,198 passed /
4 skipped / 0 failed, against the 11,196/4/0 baseline at
|
||
|---|---|---|
| .github | ||
| .vscode | ||
| docs | ||
| memory | ||
| references | ||
| src | ||
| tests | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .gitmodules | ||
| AcDream.slnx | ||
| AGENTS.md | ||
| analyze_flap_live.py | ||
| CLAUDE.md | ||
| find_burst.py | ||
| launch-a6-issue98-capture.ps1 | ||
| launch-a6-issue98-cottage-gfxobj-dump.ps1 | ||
| launch-a6-issue98-polydump.ps1 | ||
| launch-flap-capture.ps1 | ||
| launch-flap-churn.ps1 | ||
| launch-flap-verify.ps1 | ||
| NOTICE.md | ||
| README.md | ||
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.pakproduced byAcDream.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
GameRuntimeis hosted by both the graphical client andAcDream.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 1–3, 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
#225retains 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.datclient_cell_1.datclient_highres.datclient_local_English.dat
- A machine-local
acdream.pakbuilt 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/:
- Search the named retail pseudo-C and headers by
class::method. - Use the older Ghidra chunks only when the named oracle is insufficient.
- Cross-reference ACE and the relevant client/viewer implementation.
- Record readable pseudocode and exact constants/order.
- Port the retail mechanism into the correct modern owner.
- Add conformance, lifecycle, and failure-boundary tests.
- Run the automated gate and the appropriate connected or visual gate.
- 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.