Two linked issues both rooted in skipping parts of the retail physics chain.
## 1. Remote staircase on slopes — Euler never integrated between UPs
TickAnimations called rm.Body.update_object(now) for remote integration, but
PhysicsBody.update_object gates on MinQuantum = 1/30s (retail FUN_00515020
early-return). At our 60fps render tick (~16 ms), deltaTime < MinQuantum on
almost every frame → early return AND LastUpdateTime never advances → position
effectively never integrates. Remote Position changed only on UP hard-snap,
producing visible teleport strides uphill (the "staircase" the user reported).
Fix: call UpdatePhysicsInternal(dt) directly for the remote tick — the same
pattern PlayerMovementController.cs:358 uses for the local player. Wire
ResolveWithTransition in afterwards so the remote's Euler-advanced position
gets swept through the same retail collision chain (find_env_collisions +
find_obj_collisions + step_down + 6-path BSP dispatcher) that the local
player already goes through.
New field RemoteMotion.CellId tracks the remote's cell across frames; set
from UpdatePosition.p.LandblockId and updated from transition output.
## 2. Local player floating on downhill slopes — ContactPlane not persisted
Running a character down a slope faster than ~0.5 m/s vertical: per-frame
Euler moves feet horizontally (no Z component since velocity is world-XY).
After Euler, feet are above the new-XY terrain. ValidateWalkable takes the
"above surface" branch without setting a contact plane, DoStepDown probes
~4 cm down (the retail StepDownHeight default), fails to find the surface
8-10 cm below, and the character stays at the old Z. Over a sustained
descent this accumulates into a visible hover.
Retail's PhysicsObj carries ContactPlane + ContactPlaneCellID as persistent
fields (ACE PhysicsObj.cs:2598-2604 get_object_info → InitContactPlane).
Each transition call seeds CollisionInfo.ContactPlane from the previous
frame's plane. That seed is what lets AdjustOffset project horizontal
velocity onto the slope surface — so the Euler offset acquires a Z
component matching the slope and the sphere tracks terrain without needing
step-down to do the catch-up every frame.
Fix: add PhysicsBody.ContactPlane* fields mirroring PhysicsObj's. Extend
ResolveWithTransition with an optional `body` parameter; when provided, seed
the transition's CollisionInfo from body.ContactPlane at the start, copy
back (preferring current, falling back to LastKnown) at the end. Both local
(PlayerMovementController) and remote (TickAnimations) pass their body.
Verified live: DIAG samples showed pre/post/resolved Z all exactly equal
before the MinQuantum bypass (Euler frozen). After bypass, deltas dropped
to floating-point noise on slopes for remotes. Local hover on downhill
resolved in separate visual pass.
All 717 tests green. No API breaks (ResolveWithTransition's body param is
optional, backwards-compatible).
Cross-refs:
- decompile: FUN_00515020 update_object, FUN_005111D0 UpdatePhysicsInternal,
FUN_005148A0 transition init
- ACE: PhysicsObj.cs:2586-2621 get_object_info, Transition.cs:613-620 InitContactPlane
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Our LandblockMesh, terrain.vert corner tables, and TerrainSurface.SampleZ
used the OPPOSITE diagonal for each CellSplitDirection enum value from
what ACE (and the decompiled retail client at FUN_00532a50) picks for the
same sign bit. Same formula, same sign-bit mapping, inverted geometry.
Symptom: remote players rendered at server-broadcast Z hovered or clipped
by up to ~1m on sloped cells. Flat cells masked the bug because all four
corner heights were equal so any triangle pair returned the same Z. Live
diagnostic confirmed +0.79m hover on cell (7,5) at lb(AA,B4) — a ~20°
slope — while flat neighbors agreed to floating-point noise.
Three coordinated edits so CPU mesh + GPU corner lookup + CPU sampler all
agree on the retail geometry:
- LandblockMesh: SWtoNE branch now emits {BL,BR,TR}+{BL,TR,TL} (y=x cut),
SEtoNW emits {BL,BR,TL}+{BR,TR,TL} (x+y=1 cut).
- terrain.vert: corner-index tables updated to match.
- TerrainSurface.SampleZ: swapped the two branches' interpolation.
After the fix, 19 live DIAG samples across flat + two slope transitions
all land within 0.01m of server Z. Staircase pattern during remote motion
on slopes is a separate bug (no per-frame collision resolution) and will
be addressed via the transition/FindValidPosition port.
Cross-verified against: ACE LandblockStruct.ConstructPolygons lines 221-
244, decompiled retail FUN_00532a50 (chunk_00530000.c:2235), ClientReference
IsSWtoNECut (tests/AcDream.Core.Tests/Terrain/ClientReference.cs).
Updated test SplitDirection_TerrainSurface_AgreesWith_TerrainBlending
with corrected expectations (Z values swap between the two branches).
All 717 tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Ports the retail client's client-side remote-entity motion pipeline
verbatim per the decompile research. Every remote now runs its own
PhysicsBody + MotionInterpreter + AnimationSequencer stack — retail has
no special "interpolator" for remotes, it runs the full motion state
machine on every entity. Now we do too.
## What changed
### Parser fixes (CreateObject, UpdateMotion)
Wire flag bits for InterpretedMotionState (per ACE MovementStateFlag enum):
CurrentStyle=0x01, ForwardCommand=0x02, ForwardSpeed=0x04,
SideStepCommand=0x08, SideStepSpeed=0x10, TurnCommand=0x20, TurnSpeed=0x40
Previously we only extracted CurrentStyle + ForwardCommand + ForwardSpeed
and SKIPPED the side/turn fields entirely. Result: we had zero rotation-
or strafe-intent data from the server — impossible to render turn or
sidestep animations. Now ServerMotionState carries all 7 fields and the
parser reads the bytes in ACE's write order (style, fwd, side, turn, then
fwdSpd, sideSpd, turnSpd).
### RemoteMotion (new per-remote struct in GameWindow)
Each remote gets its own PhysicsBody + MotionInterpreter + observed
angular velocity. Replaces the earlier shortcut RemoteInterpolator
(deleted — retail has no such thing).
On UpdateMotion:
- ForwardCommand flag absent → stop signal (reset to Ready) per
retail FUN_0051F260 bulk-copy semantics (absent = Invalid = default).
- Forward + sidestep + turn each route through DoInterpretedMotion,
exactly as retail FUN_00528F70 does.
- Animation cycle selection: forward wins if active, else sidestep,
else turn, else Ready. Matches the user's observation that retail
plays turn animation when only turning.
- Turn command seeds ObservedOmega = π/2 × turnSpeed (from Humanoid
MotionData.Omega.Z ≈ π/2 per decompile).
- Turn absent → ObservedOmega = 0 (stops rotation immediately).
On UpdatePosition:
- Hard-snap Body.Position + Body.Orientation per retail FUN_00514b90
set_frame (direct assignment, no slerp — retail does not soft-snap).
- HasVelocity + |v| < 0.2 → StopCompletely + SetCycle(Ready).
- ForwardSpeed=0 on wire is a VALID stop signal (ACE sends this when
alt releases W); previously we defaulted to 1.0, causing the "slow
walk that never stops" symptom.
Per-tick:
- apply_current_movement → Body.Velocity via get_state_velocity
(retail FUN_00528960: RunAnimSpeed × ForwardSpeed in body-local,
rotated by orientation).
- Manual omega integration: Orientation *= quat(ObservedOmega × dt).
Bypasses PhysicsBody.update_object's MinQuantum=1/30s gate that
was eating every-other-tick rotation updates at our 60fps render
rate — the cause of the persistent "rotation snaps every UP" bug.
- update_object still called for position integration and the motion
subsystem it drives.
### AnimationSequencer synthesis extension
Added omega synthesis for TurnRight/TurnLeft cycles (same pattern as
the earlier velocity synthesis): when the Humanoid dat leaves HasOmega
clear, SetCycle synthesizes CurrentOmega = ±π/2 × speedMod on Z so
dead-reckoning and stop detection can read a non-zero omega for turn
cycles.
### Stop-detection heuristic removed
No more 300ms/2000ms/5000ms idle timers. Retail's stop signal is
explicit (UpdateMotion with ForwardCommand flag absent → Ready); we
handle it directly. Client-side timers were a source of flicker during
normal running.
## Confirmed working
- Walking (matches retail speed + leg cadence)
- Running (matches retail speed + leg cadence)
- Strafing (body moves sideways + strafe animation plays)
- Turning while stationary (body rotates smoothly + turn animation plays)
- Turning while running (body rotates + leg anim continues)
- Stopping (instant stop, no slow-walk tail)
All 717 tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Two related bugs in the motion/animation pipeline:
1. Player's local animation was getting reset to speedMod=1.0 every ~100ms.
ACE's BroadcastMovement echoes the player's own motion back via
UpdateMotion. When ACE's ForwardSpeed == 1.0, the ForwardSpeed flag is
omitted (InterpretedMotionState.BuildMovementFlags), so our wire parser
returns null and we default to speedMod=1.0 — clobbering the
locally-authoritative 2.375 × runRate that UpdatePlayerAnimation just
set. Legs would crank up to full cadence for one frame then get slammed
back to walking rate.
Fix: for the player's own guid, skip the wire-echo SetCycle entirely.
UpdatePlayerAnimation is the authoritative driver for the local
player's animation; the server echo is only useful for observers of
other characters. User-confirmed: legs now hold their full cadence.
2. Remote entities teleported between UpdatePositions because the
sequencer's CurrentVelocity was always zero (Humanoid dat ships every
locomotion MotionData with Flags=0x00, so EnqueueMotionData leaves
CurrentVelocity at Vector3.Zero). Dead-reckoning's Priority 1
(sequencer velocity) never triggered, falling through to EMA which
has bootstrap lag + gets polluted by teleport-class server snaps.
Fix: synthesize CurrentVelocity in SetCycle from the retail locomotion
constants (WalkAnimSpeed=3.12, RunAnimSpeed=4.0, SidestepAnimSpeed=1.25)
× speedMod, matching the decompiled get_state_velocity (FUN_00528960)
which uses these same constants directly instead of MotionData.Velocity.
The dat's HasVelocity field is reserved for non-locomotion motions
(kick-off velocities, flying creatures, etc).
Diag confirmed synthesis fires and DR picks it up with src=seq and
correct magnitude. More visual polish may still be needed for the
"lagging remote" symptom — see follow-up.
Also adds `PlayerMovementController.BodyVelocity` utility getter for HUD/
debug use, and `ACDREAM_ANIM_SPEED_SCALE` env var as a tunable knob for
visual pacing overrides.
All 717 tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The decompiled get_state_velocity (FUN_00528960) literally computes
`RunAnimSpeed * ForwardSpeed` — a 4.0 × runRate world velocity. That
matches retail only when the character's MotionTable happens to bake
MotionData.Velocity.Y = 4.0 on RunForward (true for Humanoid, not
necessarily for other creatures or swapped weapon-style cycles).
When MotionData.Velocity ≠ RunAnimSpeed, the body's world velocity
drifts away from the animation's baked-in root-motion velocity, and
you see the classic "legs cycle too slowly for how fast the body is
sliding" visual bug. User reports ~30% discrepancy ("running animation
is too slow"), consistent with Humanoid RunForward's actual dat
Velocity being ~3.0 rather than the 4.0 constant.
The fix per r03 §1.3: physics body velocity = MotionData.Velocity ×
speedMod. That's exactly what AnimationSequencer.CurrentVelocity
already exposes. Route it into MotionInterpreter via an opt-in
Func<Vector3> accessor. When wired, get_state_velocity uses the
sequencer's cycle velocity as the primary forward-axis drive; when
unwired (tests, physics bodies without a sequencer), falls back to
the decompiled constant path — byte-compatible with retail on the
shapes where it actually matters.
The RunAnimSpeed × rate max-speed clamp at the bottom of
FUN_00528960 stays intact — Option B only replaces the *drive*, not
the clamp. 20 m/s phantom MotionData can't teleport the player.
Wiring: GameWindow attaches `playerAE.Sequencer.CurrentVelocity` to
`_playerController` on Tab-player-mode entry. The sequencer is always
built before the player enters chase mode, so timing is safe.
Sidestep continues to use SidestepAnimSpeed — the sequencer only
tracks the current forward cycle, so strafe is a separate axis.
6 new MotionInterpreterTests verify: accessor overrides constant path,
zero Y falls back to constant (link transitions), clamp still applies,
Ready state doesn't leak accessor value, sidestep axis is untouched.
All 717 tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Before: CurrentVelocity was a pass-through of the current AnimNode's
Velocity. So during a stance transition, while the link animation
played (with no velocity of its own), CurrentVelocity returned (0,0,0)
and remote dead-reckoning briefly stopped advancing the entity. Visible
as a hitch at every idle → walk or walk → run transition.
Retail's model (ACE Sequence.cs L16-L17, L127-L130): Velocity and Omega
are Sequence-wide fields updated by MotionTable.add_motion's
Sequence.SetVelocity call (MotionTable.cs L358-L370). Every time a new
MotionData is appended, the sequence velocity is REPLACED by that data's
velocity × speedMod. In SetCycle's rebuild path the order is:
1. clear_physics → zero
2. add_motion(link) → velocity = link's (typically 0)
3. add_motion(cycle) → velocity = cycle's (the real walk/run velocity)
After step 3, Sequence.Velocity is the CYCLE's velocity even though
CurrAnim is the link node. So dead-reckoning reads the cycle's velocity
from frame zero of the transition — no stutter.
This commit:
- Converts AnimationSequencer.CurrentVelocity / CurrentOmega from
per-node computed properties to sequence-wide private-set properties.
- Adds ClearPhysics() helper (mirrors Sequence.clear_physics).
- EnqueueMotionData now updates the sequence velocity/omega (matching
add_motion's SetVelocity semantics). Only replaces when the
MotionData's HasVelocity/HasOmega flags are set — zero-HasVelocity
modifiers don't zero the running cycle, matching retail.
- SetCycle's rebuild path calls ClearPhysics before the new add_motion
chain (matches MotionTable.cs L100-L101, L152-L153).
- MultiplyCyclicFramerate scales the sequence-wide velocity/omega
instead of per-node fields — algebraically equivalent to retail's
subtract_motion(old) + combine_motion(new) pair in change_cycle_speed.
New test: CurrentVelocity_PersistsThroughLinkTransition — verifies that
after SetCycle enqueues [link][cycle], CurrentVelocity is the cycle's
velocity even during the link frames. Catches the old bug directly.
All 659 tests pass (was 658).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
UpdateMotion's InterpretedMotionState payload includes not just
ForwardCommand but a whole Commands[] list of MotionItem entries — each
carrying an Action (attack, portal, skill use), Modifier (jump,
stop-turn), or ChatEmote (Wave, BowDeep, Laugh) that should overlay the
current cycle. The old parser stopped reading after ForwardSpeed, so
emotes/attacks/deaths never reached the sequencer and NPCs just sat in
their idle cycle.
Three parts:
1. New MotionItem wire record in ServerMotionState — carries Command
(u16), PackedSequence (u16 with IsAutonomous bit + 15-bit stamp),
and Speed (f32). Mirrors ACE Network/Motion/MotionItem.cs.
2. Both UpdateMotion.TryParse and CreateObject.TryParseMovementData
now read the full InterpretedMotionState: all 7 flag fields
(CurrentStyle, ForwardCommand, SidestepCommand, TurnCommand,
ForwardSpeed, SidestepSpeed, TurnSpeed) plus the numCommands ×
MotionItem tail. The packed u32 encodes flags in low 7 bits and
command count in bits 7+ (see ACE InterpretedMotionState.cs:131).
3. New MotionCommandResolver — reconstructs the 32-bit MotionCommand
class byte from a 16-bit wire value via a reflection-built lookup
of DatReaderWriter.Enums.MotionCommand. Server serializes as u16
(ACE InterpretedMotionState.cs:139) and we need the class to route:
- 0x10xxxxxx Action / 0x20xxxxxx Modifier / 0x12,0x13 ChatEmote →
PlayAction (resolves from Modifiers or Links dict, overlays on
current cycle)
- 0x40xxxxxx SubState → SetCycle (cycle change)
4. OnLiveMotionUpdated in GameWindow dispatches each command:
- SubState class (0x40xxx) → SetCycle (treated same as
ForwardCommand)
- Action/Modifier/ChatEmote → PlayAction — the link animation
plays once then drops back to the current cycle naturally
(matches retail's action-queue pattern in CMotionInterp
DoInterpretedMotion, decompile FUN_00528F70).
Result: NPCs now animate attacks, waves, bows, death throes, and other
one-shots that ACE broadcasts via the Commands list rather than the
primary ForwardCommand field. Combined with the dead-reckoning + speed-
scaling from the prior commits, remote characters look visually correct
during the full motion spectrum (idle → walk → run → attack → death).
Tests: 2 new UpdateMotion wire-format tests (ForwardSpeed parse, full
Wave command list parse) + 19 new MotionCommandResolver reconstruction
tests covering SubState, Action, and ChatEmote classes. 654 tests green
(was 633).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
When the server broadcasts a mid-run UpdateMotion with a different
ForwardSpeed (e.g. the player's RunRate changes due to stamina / skill
update), acdream must NOT restart the cycle — that would reset the
footstep cursor and look like a visible twitch. Retail handles this via
Sequence.multiply_cyclic_animation_framerate (ACE
references/ACE/Source/ACE.Server/Physics/Animation/Sequence.cs L277-L287),
which walks the cyclic tail of the queue and scales each node's
framerate by newSpeed / oldSpeed. MotionTable.change_cycle_speed
(MotionTable.cs L372-L379) is the caller from the same-motion path in
GetObjectSequence (L132-L139).
This commit:
1. Adds AnimNode.MultiplyFramerate(factor) — scales a single node's
framerate. Retail also swapped StartFrame↔EndFrame for negative
factors; acdream keeps StartFrame ≤ EndFrame as an invariant and
encodes direction via Framerate sign (see existing comment in
LoadAnimNode), so we only scale. Valid because callers only ever
pass positive factors from UpdateMotion ForwardSpeed.
2. Adds AnimationSequencer.MultiplyCyclicFramerate(factor) — walks
_firstCyclic through the tail and calls node.MultiplyFramerate(factor).
Also scales each node's Velocity and Omega by the same factor so
CurrentVelocity / CurrentOmega stay aligned with playback — matches
ACE's subtract_motion + combine_motion pair in change_cycle_speed.
3. Adds AnimationSequencer.CurrentSpeedMod public property — starts at
1.0, updated by SetCycle on both restart and mid-cycle rescale.
4. Adds a speed-change fast-path to SetCycle: when the (style, motion)
pair matches the current cycle and signs agree,
MultiplyCyclicFramerate(newSpeed/oldSpeed) is called instead of
rebuilding the queue — the cursor stays where it is and the animation
continues at the new rate.
5. Wires InterpretedMotionState.ForwardSpeed from UpdateMotion through
to SetCycle in OnLiveMotionUpdated. ACE omits the ForwardSpeed flag
when speed == 1.0 (InterpretedMotionState.cs:101-103), so we default
missing/zero values to 1.0.
Tests: 4 new sequencer tests covering MultiplyCyclicFramerate,
cursor preservation across speed changes, the same-motion-different-speed
fast-path, and the same-motion-same-speed no-op guard. 632 tests green
(was 628).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds IAnimationHookSink + AnimationHookRouter for fan-out of animation
hooks to downstream subsystems (audio, particles, combat, renderer
mutators). GameWindow.TickAnimations now drains ConsumePendingHooks
every tick and broadcasts each hook via the router with the entity's
world position pre-computed.
The router is a composite sink: register N sinks once at startup, each
sees every hook. Registration is idempotent, unregister works, and a
throwing sink no longer poisons dispatch (each OnHook call is wrapped in
try/catch so one bad subsystem can't halt the whole animation tick).
A NullAnimationHookSink is provided for headless tests / offline mode.
6 router tests verify: single/multi sink fan-out, idempotent register,
unregister, throwing-sink isolation, null-sink no-op.
Total: 376 Core tests + 109 Core.Net = 485 (up from 479).
This closes Phase E.1 plumbing; E.2 (audio) and E.3 (particles) will
each register a concrete sink that translates their hook types into
real-world effects.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
AnimationSequencer now walks every integer frame boundary crossed in a
tick (ACE Sequence.update_internal pattern), dispatching AnimationHook
objects whose Direction matches the playback direction (Forward or
Backward) or is Both. Mirrors ACE's Sequence.execute_hooks exactly.
New public API:
- ConsumePendingHooks() drains all hooks fired since last call, including
AnimationDone sentinel on link-node drain (emote/attack completion).
- ConsumeRootMotionDelta() drains accumulated PosFrames root motion;
AFrame.Combine (forward) / AFrame.Subtract (backward) applied per
crossed frame to match retail.
- CurrentVelocity / CurrentOmega expose the active MotionData's velocity
and omega (scaled by speedMod at enqueue), letting downstream physics
integrate the animation-driven motion.
All 27 AnimationHookType variants (SoundHook, AttackHook,
CreateParticleHook, ReplaceObjectHook, DefaultScriptHook, SetOmegaHook,
TransparentHook, ScaleHook, SetLightHook, etc.) now flow through the
hook queue. Consumers in E.2/E.3 (audio + particles) will route them to
the right subsystems.
9 new tests cover: forward-hook crossing fires exactly once, Both-direction
fires in either direction, Forward-only suppressed on reverse playback,
Backward fires on reverse, PosFrames accumulation + drain, Velocity
exposure + speedMod scaling, AnimationDone fires on link drain.
Build green; 470 tests → 479 (361 Core + 9 new E.1 hook tests + 109 Net).
Ref: docs/research/deepdives/r03-motion-animation.md §5 (hooks), §7.1-7.2
(PosFrames), §7.3 (negative framerate).
Ref: ACE Sequence.cs:262 (execute_hooks), Sequence.cs:351-443
(update_internal per-frame crossing walk).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The actual retail behavior for jump animations is a plain SubState swap —
NOT an Action overlay as I'd initially guessed. MotionCommand.Falling
(0x40000015) is a SubState cycle whose motion-table entries handle the
whole jump lifecycle:
- Links[(stance, RunForward)][Falling] = leap-into-air link
- Cycles[(stance, Falling)] = airborne cycle (loops)
- Links[(stance, Falling)][Ready/...] = landing link back to normal
Empirical verification from the diagnostic dump:
Links[0x003D0007] has 3 inner entries:
inner key: 0x41000003 (Ready)
inner key: 0x45000005 (WalkForward)
inner key: 0x40000015 (Falling) ← jackpot
SetCycle() already handles SubState + Links + Cycles resolution correctly,
so the whole fix is three lines:
if (!result.IsOnGround)
animCommand = MotionCommand.Falling;
What's in this commit:
- Added MotionCommand.Falling (0x40000015) constant + comments explaining
the retail jump-is-a-SubState flow
- GameWindow.UpdatePlayerAnimation swaps to Falling when airborne (the
cleanest possible implementation — motion table does all the work)
- Kept AnimationSequencer.PlayAction infrastructure (ported via Links
fallback + Modifiers fallback). Not needed for jump, but perfectly
valid for emotes like /wave, /bow (found in the same Links dict as
inner keys 0x13000080-0x13000083) and eventual combat attacks
- Kept MotionCommand.Jump / Jumpup / FallDown constants (unused for now
but useful reference if non-humanoid motion tables use them)
- Removed all diagnostic logging
What was learned (for future motion work):
- Retail's MotionTable.Cycles dict holds SubState loops (Ready, Walk,
Run, Falling, Crouch, etc.) by (style<<16) | (motion & 0xFFFFFF)
- MotionTable.Links dict holds TRANSITIONS between motions: the OUTER
key is the (style, fromMotion) combo; the INNER key is the TARGET
motion. The stored MotionData IS the link animation played during
the transition. This is what ACE's get_link traverses.
- MotionTable.Modifiers dict holds overlay motions (mask 0x20) — rare
for humanoids, only 8 TurnRight/SideStepRight stance variants
- Actions (mask 0x10) in retail ALSO go through Links — they're
transition animations FROM current substate, not overlays. Use
PlayAction (now correctly routed to Links dict) for them.
Jump animation now works retail-faithfully for running + jumping off.
Standing-jump behavior depends on whether the player's motion table
has a Ready→Falling link; SetCycle's fallback chain should handle it
via the style-level catch-all if the direct link is absent.
470 tests pass. Build clean.
Adds AnimationSequencer.PlayAction as the proper path for Action and
Modifier-class motions (the MotionTable.Modifiers dict, distinct from
Cycles). Action nodes are inserted before the looping cyclic tail so
they drain once and the cycle resumes naturally — leveraging the
sequencer's existing "non-looping head drains, cyclic tail wraps"
queue semantics.
What this does:
- New AnimationSequencer.PlayAction(motionCommand, speedMod=1f):
- Resolves (style<<16) | (motion&0xFFFFFF) from MotionTable.Modifiers
- Falls back to (motion&0xFFFFFF) plain key
- Silent no-op when not found (some motion tables lack these)
- Inserts AnimNodes before _firstCyclic; re-points the cursor when on
the cyclic tail so the action plays immediately
- New MotionCommand.Jump (0x2500003B) + MotionCommand.FallDown (0x10000050)
constants.
- GameWindow.UpdatePlayerAnimation fires PlayAction(Jump) on
result.JumpExtent.HasValue and PlayAction(FallDown) on JustLanded.
Key research finding: retail does NOT animate jumps.
- ACE Player.HandleActionJump explicitly clears PendingMotions and sets
IsAnimating=false during a jump (Player.cs:914-915).
- Empirical verification: the player humanoid's MotionTable only has 8
Modifier entries — all TurnRight/SideStepRight stance variants. No
Jump (0x2500003B) or FallDown (0x10000050) entries.
- Jump is a physics-only action: the character keeps whatever cycle
was active (walk/run/idle) while the physics body arcs through the
air. There is no "raise arms to jump" pose in retail.
PlayAction is still called on jump/land as a safety hatch for creature
Setups that DO carry leap animations in their Modifiers dict (drudge
jumps, monster pounces, etc.). For player humanoids it's a no-op. The
infrastructure is also ready for future emote/combat actions that
legitimately use the Modifiers dict.
470 tests pass, build clean.
Adds the first on-screen HUD for the dev client plus today's mouse-control
refinements. Also lands yesterday's scenery-alignment changes that were
left uncommitted in the working tree.
Overlay:
- BitmapFont rasterizes a system TTF via StbTrueTypeSharp into a 512x512
R8 atlas at startup (Consolas on Windows, DejaVu/Menlo fallbacks)
- TextRenderer batches 2D quads in screen-space with ortho projection;
one shader + two draw calls (rect then text) for panel backgrounds
under glyphs
- DebugOverlay composes info / stats / compass / help panels on top of
the 3D scene; toggles via F1/F4/F5/F6; transient toasts for key events
- DebugLineRenderer and its shaders (carried over from the scenery work)
are properly committed in this commit
Controls:
- Per-mode mouse sensitivity (Chase 0.15, Fly 1.0, Orbit 1.0); F8/F9 to
adjust the active mode multiplicatively (x1.2)
- Hold RMB to free-orbit the chase camera around the player; release
stays at the new angle (no snap-back)
- Mouse-wheel zooms chase distance between 2m and 40m
- Chase pitch widened to [-0.7, 1.4] so mouse-Y tilts both ways from
the default neutral angle
Scenery alignment (carried from yesterday's session):
- ShadowObjectRegistry AllEntriesForDebug + Scale field
- SceneryGenerator uses ACViewer's OnRoad polygon test + baseLoc +
set_heading rotation
- BSPQuery dispatchers accept localToWorld so normals/offsets transform
correctly per part
- TransitionTypes.CylinderCollision rewritten with wall-slide + push-out
- PhysicsDataCache caches visual-mesh AABB for scenery that lacks
physics Setup bounds
The BSP collision detection runs in object-local space, but the
collision response (normals, push offsets) was being applied directly
to world-space SpherePath without rotating back to world space. For
rotated objects (trees, rocks, buildings), this caused the push
direction to be wrong — pushing the player sideways or into the
object instead of away from it.
Added localToWorld quaternion parameter to FindCollisions and all
helper methods (StepSphereDown, CollideWithPt, NegPolyHitDispatch).
All normals and offsets are now transformed via
Vector3.Transform(v, localToWorld) before being applied to SpherePath,
matching ACE's path.LocalSpacePos.LocalToGlobalVec() pattern.
Indoor cell collision uses Quaternion.Identity (cell-local = world).
Object collision passes obj.Rotation.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Replace the patched collision system (~60-70% retail) with a faithful
port of ACE's BSPTree/BSPNode/BSPLeaf/Polygon collision pipeline.
BSPQuery.cs completely rewritten (1808 lines):
- Polygon-level: polygon_hits_sphere_precise (retail two-loop test),
pos_hits_sphere, hits_sphere, walkable_hits_sphere, check_walkable,
adjust_sphere_to_plane, find_crossed_edge, adjust_to_placement_poly
- BSP traversal: sphere_intersects_poly, find_walkable, hits_walkable,
sphere_intersects_solid, sphere_intersects_solid_poly
- BSP tree-level: find_collisions (6-path dispatcher), step_sphere_up,
step_sphere_down, slide_sphere, collide_with_pt, adjust_to_plane,
placement_insert
PhysicsDataCache.cs: Added ResolvedPolygon type with pre-computed
vertex positions and face planes (matching ACE's Polygon constructor
which calls make_plane() at load time). Populated at cache time to
avoid per-collision-test vertex lookups.
TransitionTypes.cs: FindObjCollisions rewritten to use the retail
per-object FindCollisions 6-path dispatcher instead of the old
"find earliest t, then apply custom response" approach. BSP objects
now go through the same collision paths as indoor cell BSP.
The previous approach was explicitly rejected by the user after ~10
iterations of patches. This port follows the CLAUDE.md mandatory
workflow: decompile first → cross-reference ACE → port faithfully.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Indoor CellStruct PhysicsBSP collision for room walls/ceilings.
Dual sphere (body+head) from Setup dimensions.
StepUp attempts before sliding when hitting low obstacles.
FindTimeOfCollision for exact parametric BSP contact time.
Full 6-path BSP dispatcher wired into FindEnvCollisions.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Rewind to t-0.02 instead of exact contact time, plus 2cm normal
push-back. The previous 0.5cm was too small — at high speed the
sub-step could overshoot past the surface.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
When FindTransitionalPosition fails (stuck in corner, too many steps),
use the partially-resolved position instead of falling back to the
simple Resolve which has no object collision. This prevents walking
through objects when the transition can't find a clean path.
The player now stops at corners instead of clipping through.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The broad-phase rejection was using 3D distance for cylinder objects,
which includes the Z offset between player feet and cylinder base.
Trees have their origin at the base (Z=ground) while the player
sphere is at chest height (Z=ground+~2.5m). The 3D distance exceeded
the combined radius, causing the collision test to be skipped entirely.
Fix: use horizontal (XY) distance for cylinder broad-phase since
the vertical extent is checked separately in the cylinder test.
Also increase broad-phase margin from 1m to 2m.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
GetNearbyObjects now searches the player's landblock plus all 8
neighbors. Previously only searched one landblock, missing objects
near landblock boundaries — which includes most trees/rocks since
scenery is placed across the full streaming window.
Also added diagnostic logging (will strip after verification).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
When collision is detected at t=0 (already overlapping at step start),
push the sphere out along the collision normal by half-radius instead
of trying to slide with zero displacement (which gets stuck).
Returns Adjusted instead of Slid so the transition loop retries
from the pushed-out position.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Restructure FindObjCollisions to compute collision ALONG the movement
path instead of at the final position:
BSP: movement-aware SphereIntersectsPoly with front-face culling
(dot(movement, normal) < 0). Only detects faces the sphere is
approaching, matching retail Polygon.pos_hits_sphere.
Cylinder: quadratic ray-cylinder intersection computes parametric
contact time t. If t < 1.0, sphere is rewound to the contact point.
Both: find the EARLIEST collision (minimum t), rewind sphere to
contact point + small epsilon along normal, then SlideSphere.
This prevents the "walking into walls" penetration (BUG-005).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Most scenery objects (trees, rocks) use CylSphere collision from
their Setup, not PhysicsBSP. Register these in ShadowObjectRegistry
with a Cylinder collision type. FindObjCollisions now handles both:
- BSP: full polygon collision via BSPQuery (buildings, stabs)
- Cylinder: radial + vertical cylinder-sphere test (trees, NPCs)
Diagnostics showed 170 CylSphere entities vs 278 BSP entities in
the Holtburg landblock alone — this roughly doubles collision coverage.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Replace simplified BSP overlap test with retail-faithful 6-path
collision dispatcher. Sphere-intersects-poly now uses movement
vector for front-face culling (prevents wall penetration).
All paths: placement/ethereal, checkWalkable, stepDown, collide,
contact+onWalkable, and default (not in contact).
Ported from ACE BSPTree.cs/BSPNode.cs/BSPLeaf.cs/Polygon.cs,
cross-referenced against decompiled chunk_00530000.c.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Replace simplified push-out with retail-faithful SlideSphere and
AdjustOffset from transition_pseudocode.md. Crease-projection between
collision normal and contact plane produces smooth wall-sliding.
Object collision uses proper rotation transform to object-local space.
SlideSphere (section 6): computes crease direction via cross product
of collision normal and contact plane normal, projects displacement
onto the crease, then applies the correction offset. Handles three
cases: crease exists, parallel same-direction, parallel opposing.
AdjustOffset (section 6): adds safety check to keep sphere above
contact plane by computing signed distance and pushing up along Z
when the sphere dips below.
FindObjCollisions: removes ad-hoc penetration push-out, now calls
SlideSphere after BSP hit detection for proper wall-slide behavior.
Also fixes: ShadowEntry gains Rotation field, tests updated to match
Register signature, unused variables removed from GameWindow.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Register static entities into terrain cells during streaming.
Transition system queries nearby objects and runs BSP collision.
Player can no longer walk through trees and buildings.
- ShadowObjectRegistry: 24m×24m cell index, Register/Deregister/
RemoveLandblock/GetNearbyObjects matching retail AC's approach
- PhysicsEngine: ShadowObjects property + DataCache wiring point;
RemoveLandblock now also clears shadow objects; TryGetLandblockContext
helper lets Transition resolve landblock id+offset for a world pos
- Transition.FindObjCollisions: queries registry, broad-phase sphere test,
narrow-phase BSPQuery.SphereIntersectsPoly in object-local space,
returns Slid on hit to redirect movement along the surface
- GameWindow.ApplyLoadedTerrainLocked: registers each static entity after
physics BSP data is cached; selects radius from BSP bounding sphere or
Setup.Radius; wires PhysicsDataCache into engine on OnLoad
- 16 new ShadowObjectRegistry unit tests, all 361 tests green
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Replace simple Z-snap PhysicsEngine.Resolve with ResolveWithTransition
that uses the ported CTransition sphere-sweep pipeline. Movement is
subdivided into sphere-radius steps, terrain collision tested at each
step with step-down for ground contact maintenance.
Falls back to simple Resolve if transition fails. Player controller
now passes pre/post integration positions to the transition system.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
SmallVelocity threshold (0.25 m/s) in UpdatePhysicsInternal was zeroing
velocity every frame while airborne at the jump apex. With vel~0.01 m/s
and gravity adding only 0.012/frame, the zeroing won every frame and
the character got stuck at peak height forever.
Fix: only apply small-velocity zeroing when OnWalkable (grounded).
While airborne, gravity must accumulate freely through the zero-crossing.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Two fixes for jump physics:
- Skip ground-snap when velocity Z > 0 (prevents immediate re-landing
at high framerates where per-frame Z delta < 0.05 snap threshold)
- Guard apply_current_movement velocity write behind OnWalkable check
(prevents MotionInterpreter.DoMotion from zeroing jump velocity on
every frame while airborne)
- Guard PlayerMovementController velocity replacement behind OnWalkable
(preserves momentum during airborne flight)
Jump works locally but server packet not yet sent (BUG-002).
Facing direction mismatch logged as BUG-003.
RunRate not verified as BUG-004.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Port FindTransitionalPosition, TransitionalInsert, FindEnvCollisions,
AdjustOffset, DoStepDown, ValidateTransition from transition_pseudocode.md.
Outdoor terrain collision with step-down ground contact. Indoor BSP and
object collision deferred to subsequent tasks.
Also adds PhysicsEngine.SampleTerrainZ() which dispatches the terrain Z
query to the right registered landblock by world-space XY position.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
SpherePath, CollisionInfo, ObjectInfo, TransitionState, PhysicsGlobals.
Types match the pseudocode from transition_pseudocode.md, faithful to
decompiled CTransition + ACE Transition.cs naming.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Load PhysicsBSP and PhysicsPolygons from GfxObj dats during streaming.
BSPQuery.SphereIntersectsPoly traverses the tree for collision detection.
Ported from decompiled FUN_00539270, cross-ref ACE BSPNode.sphere_intersects_poly.
- PhysicsDataCache: thread-safe ConcurrentDictionary-backed cache of GfxObjPhysics
(BSP tree + polygon dict + vertex array) and SetupPhysics (capsule dimensions).
CacheGfxObj/CacheSetup are idempotent — safe to call at every dat load site.
- BSPQuery.SphereIntersectsPoly: recursive BSP descent with bounding-sphere broad
phase, leaf polygon test via existing CollisionPrimitives.SphereIntersectsPoly
(FUN_00539500), and splitting-plane classification for internal nodes.
- GameWindow: _physicsDataCache populated at all GfxObj/Setup dat load sites
(streaming worker path, live-spawn path, ApplyLoadedTerrain render-thread path).
- 6 new unit tests covering null node, bounding-sphere miss, leaf hit, no-contact,
internal node recursion, and empty cache behaviour. All 447 tests green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Implements IWeenieObject with GetRunRate and GetJumpHeight from
decompiled client, cross-referenced against ACE MovementSystem.
Default skills (Run=200, Jump=100) used until skill parsing ships.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Sprint 2 of the audit remediation plan.
Re-enables the outdoor→indoor portal transition in PhysicsEngine with
an added containment check: after detecting a portal plane crossing,
verify the target cell's floor polygon actually covers the candidate
position AND the floor Z is within step height of the player's Z.
This prevents the wall-bounce bug (where portal planes on upper
floors captured outdoor positions) while allowing genuine doorway
transitions. Without full CellBSP, the SampleFloorZ + Z-proximity
check is the best available approximation per the indoor transition
research (docs/research/acclient_indoor_transitions_pseudocode.md).
Source: ACE EnvCell.find_transit_cells validates via
sphere_intersects_cell in the target cell's local space. Our
SampleFloorZ + Z check is the equivalent without BSP.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
ROOT CAUSE of "twitching" / stuck-on-frame-0 for reverse animations
(TurnRight with negative dat framerate, StrafeRight, etc.):
The frame swap (StartFrame↔EndFrame for negative speed) made EndFrame=0,
and GetStartFramePosition returned (0+1)-eps = 0.999. The cursor
oscillated between 0.0 and 0.999 — floor() of anything in [0,1) is
always 0, so only frame 0 ever rendered.
Fix: DON'T swap. Keep StartFrame=0, EndFrame=N-1 regardless of speed
sign. GetStartFramePosition for negative speed returns (N-1+1)-eps ≈ N,
so the cursor starts near the high end and counts down through ALL
frames. The Advance loop's reverse boundary check uses StartFrame (the
low value) correctly without the swap.
Also strips diagnostic logging from AnimationSequencer and GameWindow.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Complete ground-up rewrite of AnimationSequencer.cs using the retail AC client
pseudocode (docs/research/acclient_animation_pseudocode.md) as the direct
translation guide. Every key algorithmic difference from the previous patched
implementation is addressed:
1. _framePosition is now double (64-bit), matching Sequence+0x30 in the retail
client binary. Previously float, which accumulated rounding error over long
sessions.
2. FUN_005267E0 (multiply_framerate) is now correctly applied at node load time:
negative speedScale swaps startFrame↔endFrame so the advance loop counts DOWN
from (EndFrame+1)-epsilon toward EndFrame, exactly matching the retail layout.
3. update_internal (FUN_005261D0) is faithfully ported: one loop handles both
forward and reverse; boundary detection uses EndFrame as the lower bound for
reverse playback (matching the post-swap field semantics); remainder time
propagates correctly across node boundaries for large dt values.
4. GetStartFramePosition (FUN_00526880) and GetEndFramePosition (FUN_005268B0)
formulas are now correct: negative speed starts at (EndFrame+1)-epsilon,
ends at StartFrame; positive speed starts at StartFrame, ends at (EndFrame+1)-epsilon.
5. advance_to_next_animation (FUN_00525EB0) wraps to _firstCyclic when the
linked list is exhausted, matching the retail loop-forever semantics.
6. adjust_motion (ACE MotionInterp.cs:394-428) remapping is unchanged and
correct: TurnLeft→TurnRight, SideStepLeft→SideStepRight (negate speed),
WalkBackward→WalkForward (negate×0.65 BackwardsFactor).
7. SlerpRetailClient (FUN_005360d0) is unchanged — the pseudocode confirms the
existing implementation is correct.
AnimationSequencerTests grows from 9 to 17 tests:
- Negative-speed playback: TurnLeft remaps and cursor initializes near EndFrame+1
- Reverse frame position decreases (not increases) over time
- Reverse wrap at start boundary recovers and loops
- advance_to_next_animation: link node drains then enters cycle
- Cycle loops repeatedly without crash or position drift
All 431 tests green (109 net + 322 core).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Backward-playback nodes (TurnLeft, SideStepLeft) have LowFrame >
HighFrame after multiply_framerate swaps them. Math.Clamp(x, 19, 0)
throws because min > max.
Fix: compute rangeLo/rangeHi from Min/Max of Low/High, use those
for clamping. Also step nextIdx in the playback direction (forward
+1, backward -1) instead of always +1.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
ROOT CAUSE FIX for missing left-side animations.
The AC client's MotionTable has NO cycles for TurnLeft (0x000E),
SideStepLeft (0x0010), or WalkBackward (0x0006). The real client
calls adjust_motion() which remaps these to their right-side
equivalents with NEGATIVE speed before looking up the cycle. Then
multiply_framerate() swaps LowFrame↔HighFrame so the animation
plays backward.
Source: ACE MotionInterp.cs:394-428, decompiled FUN_005267E0.
Changes:
- AnimationSequencer.SetCycle: adds adjust_motion block that remaps
left→right with speed *= -1 (TurnLeft, SideStepLeft) or
speed *= -0.65 (WalkBackward = BackwardsFactor)
- LoadAnimNode: when framerate < 0, swaps Low↔High (matching the
decompiled multiply_framerate)
- GameWindow.UpdatePlayerAnimation: passes original animCommand to
SetCycle (sequencer handles remapping internally), keeps legacy
fallback for non-sequencer entities
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Port the animation playback engine from the decompiled retail client
into AcDream.Core.Physics.AnimationSequencer.
## What this adds
**AnimationSequencer** (src/AcDream.Core/Physics/AnimationSequencer.cs):
- Frame advancer: `frameNum += framerate * dt`, bounds-checks against
AnimData.HighFrame/LowFrame (with sentinel resolution for HighFrame=-1),
wraps at cycle boundaries. Matches ACE's `Sequence.update_internal`.
- Quaternion slerp (`SlerpRetailClient`): ported from decompiled
`FUN_005360d0` (chunk_00530000.c:4799-4846):
1. dot-product sign-flip to take the shorter arc
2. fallback to linear blend when 1-dot <= 1e-4 (near-parallel)
3. sin-based slerp for all other cases
4. validate weights lie in [0,1] before using sin result (retail
client validation step that guards degenerate inputs)
- Transition link resolution: `GetLink(style, fromMotion, toMotion)`
mirrors ACE's `MotionTable.get_link` positive-speed path.
DatReaderWriter layout: `Links[style<<16|(from&0xFFFFFF)]` is a
`MotionCommandData` whose `.MotionData[toMotion]` is the transition
`MotionData`. Link frames are prepended before the cyclic tail, so
idle->walk plays the short transition clip then loops the walk cycle.
- `IAnimationLoader` / `DatCollectionLoader`: thin abstraction so the
sequencer is testable offline without opening dat files.
- Public API: `SetCycle(style, motion, speedMod)` + `Advance(dt)`
returning `IReadOnlyList<PartTransform>` (Origin+Orientation per part).
**AnimationSequencerTests** (tests/...Physics/AnimationSequencerTests.cs):
14 tests, all offline, covering slerp math, frame wrap, transition link
prepend, no-link direct switch, same-motion fast path, reset.
317 tests green, 0 warnings.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Adds CollisionPrimitives.cs with C# ports of FUN_005384e0 / FUN_00539500 /
FUN_00539ba0 / FUN_00539110 / FUN_00539060 / FUN_0053a230 / FUN_0053a040 /
FUN_00538eb0 / FUN_00538f50 — covering ray-sphere, sphere-poly contact,
find-time-of-collision, face-normal computation, ray-plane intersection,
walkable checks, edge-normal slide, and sphere landing.
Key findings from cross-referencing with ACE's Polygon.cs:
- The edge-perpendicular formula is cross(N, edge) (normal × edge), matching
the retail param_1[9/10/8] order in the decompiled loops.
- find_time_of_collision uses t = (dot(origin,N)+D) / dot(dir,N); the sign
is negative when approaching from above — contact = origin − dir*t.
- land_on_sphere only succeeds when the sphere centre is within one radius of
the plane (dist < r), which is the "settling onto ground" scenario.
26 new tests green; full suite 367/367 green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The SampleZ method had the two triangle-boundary conditions swapped relative
to what the mesh index buffer actually renders, causing the physics Z to
sample from the wrong triangle on roughly half of all terrain cells. The
error could be up to 7.5 units on steep 24×24 cells, which manifested as
feet clipping into rising terrain on slopes.
Root cause (discovered via WorldBuilder-ACME-Edition exhaustive analysis):
"SWtoNE cut" means BL and TR are the *isolated* vertices; the shared
hypotenuse runs TL(0,1) → BR(1,0), so the correct dividing test is
tx+ty=1, NOT ty=tx. The old code used ty≤tx for the SWtoNE branch
(the BL→TR diagonal), which matches the SEtoNW mesh layout instead.
Fix: swap the boundary conditions for the two split cases so they match
LandblockMesh.cs's actual index buffer layout:
SWtoNE: tx+ty ≤ 1 → BL+BR+TL, else TR+TL+BR
SEtoNW: ty ≤ tx → BL+BR+TR, else BL+TR+TL
Verified by running all three formulas (acdream, ACME GetHeight, ACME
HeightSampler) against the mesh index buffer at 50 interior points across
both split types: fixed version matches 0 errors, old version had 50.
All 283 tests still pass.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The triangle-aware Z sampling from the previous commit produces exact
terrain-surface Z values, but a point-sampled Z on a tilted surface
places the character's center on the surface while their feet (which
extend horizontally) clip into the rising terrain ahead/behind.
Fix: in PlayerMovementController, sample Z 1 unit ahead in the walk
direction and add 40% of the gradient as an upward bias. This
compensates for the character's collision cylinder radius on slopes
while producing zero bias on flat ground. The bias is applied in the
movement controller (gameplay concern) not in TerrainSurface.SampleZ
(which stays exact for physics/tests).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Two fundamental terrain fixes based on the AC2D + holtburger deep dive:
1. Terrain split formula: replaced WorldBuilder's physics-path formula
(214614067/1813693831) with AC2D's render-path formula (0x0CCAC033,
0x421BE3BD, 0x6C1AC587, 0x519B8F25). The two produce different splits
for some cells. Since the render mesh uses this formula, the physics
Z sampler must match it to avoid misalignment on slopes.
2. Triangle-aware Z: replaced bilinear interpolation in TerrainSurface
with per-triangle barycentric interpolation. Each cell is split into
two triangles (using the same AC2D formula). SampleZ determines which
triangle the query point falls in, then interpolates within that
triangle. This produces Z values that exactly match the visual terrain
mesh — no more slope clipping.
Removes the multi-point Z sampling hack from PlayerMovementController
(no longer needed with exact triangle Z).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Two targeted fixes for user-reported movement bugs:
1. Wall bounce: PortalPlane.FromVertices now accepts ALL polygon vertices
(not just 3) for accurate centroid + bounding radius. IsCrossing uses
2D (XY) distance check with tight radius (no multiplier) to prevent
wall faces from triggering false indoor transitions. Walking along a
building wall no longer launches the player into the air.
2. Slope alignment: PlayerMovementController adds a slope-proportional
Z bias when walking uphill (up to +0.8 on steep slopes, grounded
only). Prevents feet from sinking into the visual terrain mesh on
slopes where the physics sample point lags the render surface.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Portal planes are infinite — IsCrossing only checked if positions
were on opposite sides of the plane, without verifying the crossing
point was near the actual portal opening. Walking 50m from a
building but crossing the same plane extension triggered false indoor
transitions, sinking the player into underground cell floors.
Fix: FromVertices now computes centroid (average of 3 vertices) and
bounding radius (max vertex distance + 2 unit padding). IsCrossing
rejects crossings where both positions are further than 2×radius
from the centroid. Only nearby crossings (within doorway range)
trigger a transition.
Also fixes jump-not-landing: the false portal transitions were
producing wrong resolvedGroundZ values during the jump arc, making
the landing check (candidateZ <= resolvedGroundZ) never true.
283 tests still green.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Adds the foundational portal-plane record for cell transition detection.
PortalPlane.FromVertices computes a normalised plane from 3 coplanar
polygon vertices via cross product + dot product; IsCrossing tests whether
a movement vector straddles the plane (strictly negative dot-product
product — exact-on-plane position returns false as specified).
4 new unit tests: normal construction, opposite-side crossing, same-side
no-crossing, start-on-plane no-crossing. All 269 tests green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
