M7 Automation: deterministic Harvester to Conveyor to Fabricator chains

Server-only production chains (never predicted): components + server systems + pure byte-only math (ProductionMath/ConveyorMath/MachineSlotMath), authoring + 3 machine prefabs wired into the Gameplay subscene, StructureCatalog rows, BuildPlace Direction/RuntimePlacedTag, Tuning, and 35 EditMode tests (catch-up gating, conveyor shuffle-invariance, SaveData v2 round-trip). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-06 15:05:15 -07:00
parent 31c4ab16d6
commit f3f65bccbf
49 changed files with 2599 additions and 1 deletions
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: d8478382df1bb34498b308c63531da1d
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
@@ -0,0 +1,123 @@
+using ProjectM.Simulation;
+using Unity.Burst;
+using Unity.Collections;
+using Unity.Entities;
+using Unity.Mathematics;
+using Unity.NetCode;
+using Unity.Transforms;
+
+namespace ProjectM.Server
+{
+    /// <summary>
+    /// One-shot server restore of player-built structures for a "Continue" session. The menu (WorldLauncher) stages a
+    /// <see cref="PendingStructure"/>/<see cref="PendingStructureIo"/> carrier in the fresh ServerWorld BEFORE the
+    /// gameplay subscene streams; this system waits (RequireForUpdate) for the streamed <see cref="StructureCatalog"/>
+    /// + <see cref="BaseAnchor"/> + a valid NetworkTime, then replays each saved structure CHARGE-FREE: Instantiate the
+    /// catalog prefab at the saved cell (preserving the baked Scale), re-stamp the rebased tick fields
+    /// (<see cref="ProductionMath.RestoreNextTick"/>; LastProcessed = now so within-session catch-up resumes from now,
+    /// never a wall-clock mint), re-tag RegionTag{Base} + RuntimePlacedTag, refill the in-flight conveyor item + the
+    /// machine I/O buffers, then DESTROY the carrier so it never runs again. The ledger/goal restore separately +
+    /// absolutely via CycleDirectorSpawnSystem's born-correct load (no double-spend, no Withdraw here).
+    /// </summary>
+    [BurstCompile]
+    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation)]
+    public partial struct BaseRestoreSystem : ISystem
+    {
+        ComponentLookup<LocalTransform> m_TransformLookup;
+        ComponentLookup<Conveyor> m_ConveyorLookup;
+
+        [BurstCompile]
+        public void OnCreate(ref SystemState state)
+        {
+            m_TransformLookup = state.GetComponentLookup<LocalTransform>(isReadOnly: true);
+            m_ConveyorLookup = state.GetComponentLookup<Conveyor>(isReadOnly: true);
+            state.RequireForUpdate<StructureCatalog>();
+            state.RequireForUpdate<BaseAnchor>();
+            state.RequireForUpdate<NetworkTime>();
+            state.RequireForUpdate(state.GetEntityQuery(ComponentType.ReadOnly<PendingStructure>()));
+        }
+
+        [BurstCompile]
+        public void OnUpdate(ref SystemState state)
+        {
+            var serverTick = SystemAPI.GetSingleton<NetworkTime>().ServerTick;
+            if (!serverTick.IsValid)
+                return;
+            uint now = serverTick.TickIndexForValidTick;
+
+            m_TransformLookup.Update(ref state);
+            m_ConveyorLookup.Update(ref state);
+
+            var anchor = SystemAPI.GetSingleton<BaseAnchor>();
+            var catalog = SystemAPI.GetBuffer<StructureCatalogEntry>(SystemAPI.GetSingletonEntity<StructureCatalog>());
+
+            var ecb = new EntityCommandBuffer(Allocator.Temp);
+
+            foreach (var (pending, ioBuf, carrier) in
+                     SystemAPI.Query<DynamicBuffer<PendingStructure>, DynamicBuffer<PendingStructureIo>>().WithEntityAccess())
+            {
+                for (int s = 0; s < pending.Length; s++)
+                {
+                    var p = pending[s];
+
+                    int entryIdx = -1;
+                    for (int i = 0; i < catalog.Length; i++)
+                        if (catalog[i].Type == p.Type) { entryIdx = i; break; }
+                    if (entryIdx < 0 || catalog[entryIdx].Prefab == Entity.Null)
+                        continue; // type not in the catalog (e.g. a save from a newer build) -> skip, don't crash
+
+                    var prefab = catalog[entryIdx].Prefab;
+                    var structure = ecb.Instantiate(prefab);
+
+                    int2 cell = new int2(p.CellX, p.CellZ);
+                    var xform = m_TransformLookup[prefab];
+                    xform.Position = BaseGridMath.CellToWorld(anchor, cell); // preserve baked Scale (FromPosition would reset it)
+                    ecb.SetComponent(structure, xform);
+
+                    ecb.SetComponent(structure, new PlacedStructure
+                    {
+                        Type = p.Type,
+                        Cell = cell,
+                        NextTick = ProductionMath.RestoreNextTick(now, p.RemainingTicks),
+                        LastProcessedTick = TickUtil.NonZero(now),
+                    });
+                    ecb.AddComponent(structure, new RegionTag { Region = RegionId.Base });
+                    ecb.AddComponent<RuntimePlacedTag>(structure);
+
+                    if (p.Type == StructureType.Conveyor && m_ConveyorLookup.HasComponent(prefab))
+                    {
+                        var conv = m_ConveyorLookup[prefab];
+                        conv.Direction = p.Direction;
+                        ecb.SetComponent(structure, conv);
+                        ecb.SetComponent(structure, new ConveyorItem { ResourceId = p.ConveyorResId, Count = p.ConveyorCount });
+                        ecb.SetComponentEnabled<ConveyorItem>(structure, p.ConveyorCount > 0);
+                    }
+
+                    // Refill machine I/O buffers from the flat io table (only slots with saved rows -> the prefab has them).
+                    bool inInit = false, outInit = false;
+                    DynamicBuffer<MachineInput> inBuf = default;
+                    DynamicBuffer<MachineOutput> outBuf = default;
+                    for (int r = 0; r < ioBuf.Length; r++)
+                    {
+                        if (ioBuf[r].StructureIndex != s)
+                            continue;
+                        if (ioBuf[r].Slot == 0)
+                        {
+                            if (!inInit) { inBuf = ecb.SetBuffer<MachineInput>(structure); inInit = true; }
+                            inBuf.Add(new MachineInput { ResourceId = ioBuf[r].ResourceId, Count = ioBuf[r].Count });
+                        }
+                        else
+                        {
+                            if (!outInit) { outBuf = ecb.SetBuffer<MachineOutput>(structure); outInit = true; }
+                            outBuf.Add(new MachineOutput { ResourceId = ioBuf[r].ResourceId, Count = ioBuf[r].Count });
+                        }
+                    }
+                }
+
+                ecb.DestroyEntity(carrier);
+            }
+
+            ecb.Playback(state.EntityManager);
+        }
+    }
+}
@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 4003027ade5ccd5418e300d87e5c5e14
@@ -0,0 +1,276 @@
+using ProjectM.Simulation;
+using Unity.Burst;
+using Unity.Collections;
+using Unity.Entities;
+using Unity.Mathematics;
+using Unity.NetCode;
+
+namespace ProjectM.Server
+{
+    /// <summary>
+    /// Server-only, deterministic conveyor transport — the MIDDLE of the M7 auto-gather chain
+    /// (Harvester → Conveyor → Fabricator). Unlike the per-machine catch-up production systems, a conveyor is a
+    /// single TRANSPORT STEP: each period-due, empty <see cref="Conveyor"/> first PULLS one item off an adjacent
+    /// upstream <see cref="MachineOutput"/> (the cell at <c>myCell − DirOffset(dir)</c> — i.e. the machine feeding
+    /// INTO this belt) onto its own <see cref="ConveyorItem"/>; then every loaded conveyor advances its item
+    /// EXACTLY one cell toward <c>myCell + DirOffset(dir)</c>. The move resolution is delegated to the pure,
+    /// unit-tested <see cref="ConveyorMath.ResolveMoves"/> so determinism is provable WITHOUT a world: sources are
+    /// processed sorted by <see cref="ConveyorMath.CellKey"/> (NOT hashmap order), occupancy is read from a
+    /// pre-move double-buffer snapshot, a destination conveyor cell accepts at most one item (only if it was empty
+    /// in the snapshot; ties → lowest CellKey wins, losers stall with no silent loss), and machine-input sink
+    /// cells always accept (deposit). Sinks are a separate set so an item leaving the belt into a fabricator's
+    /// <see cref="MachineInput"/> never collides with belt occupancy.
+    /// <para>
+    /// Mirrors <c>TurretFireSystem</c>'s now-extraction (<c>NetworkTime.ServerTick.TickIndexForValidTick</c>) +
+    /// <see cref="PlacedStructure.NextTick"/> cooldown idiom (each conveyor is period-gated the same way), and
+    /// <c>ResourceHarvestSystem</c>'s Temp-collection foreach idiom. Runs in the plain server
+    /// <c>SimulationSystemGroup</c> <c>[UpdateAfter(HarvesterProductionSystem)]</c> (after harvesters deposit, so
+    /// fresh output is pull-eligible this tick; before the fabricator consumes). All buffer/enableable mutation is
+    /// in place (toggling an enableable bit is NOT a structural change) → no ECB.
+    /// </para>
+    /// </summary>
+    [BurstCompile]
+    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation)]
+    [UpdateInGroup(typeof(SimulationSystemGroup))]
+    [UpdateAfter(typeof(HarvesterProductionSystem))]
+    public partial struct ConveyorTransportSystem : ISystem
+    {
+        [BurstCompile]
+        public void OnCreate(ref SystemState state)
+        {
+            state.RequireForUpdate<NetworkTime>();
+            state.RequireForUpdate(state.GetEntityQuery(ComponentType.ReadOnly<Conveyor>()));
+        }
+
+        [BurstCompile]
+        public void OnUpdate(ref SystemState state)
+        {
+            var serverTick = SystemAPI.GetSingleton<NetworkTime>().ServerTick;
+            if (!serverTick.IsValid)
+                return;
+            uint now = serverTick.TickIndexForValidTick;
+
+            // ---- Snapshot every conveyor once (entity, cell, direction, item, period-due) ----
+            var convEntity = new NativeList<Entity>(Allocator.Temp);
+            var convCell = new NativeList<int2>(Allocator.Temp);
+            var convDir = new NativeList<byte>(Allocator.Temp);
+            var convItemRes = new NativeList<int>(Allocator.Temp);   // 0 = empty
+            var convItemCnt = new NativeList<int>(Allocator.Temp);   // 0 = empty
+            var convDue = new NativeList<bool>(Allocator.Temp);      // period-gate satisfied this tick
+
+            foreach (var (ps, conveyor, e) in
+                     SystemAPI.Query<RefRW<PlacedStructure>, RefRO<Conveyor>>().WithEntityAccess())
+            {
+                int period = math.max(1, conveyor.ValueRO.PeriodTicks);
+
+                // Period-gate each conveyor through NextTick exactly like the production systems. A never-processed
+                // belt initialises its baseline this tick and is NOT due (mirrors NeedsInit on the machines).
+                bool due;
+                if (ProductionMath.NeedsInit(ps.ValueRO.LastProcessedTick))
+                {
+                    ps.ValueRW.LastProcessedTick = TickUtil.NonZero(now);
+                    ps.ValueRW.NextTick = TickUtil.NonZero(now + (uint)period);
+                    due = false;
+                }
+                else
+                {
+                    int cycles = ProductionMath.CyclesDue(
+                        serverTick, ps.ValueRO.NextTick, ps.ValueRO.LastProcessedTick, period, Tuning.MaxProductionCatchup);
+                    due = cycles > 0;
+                    if (due)
+                    {
+                        // A belt moves at most one cell per period; collapse any catch-up to a single step but keep
+                        // the baseline advancing so it re-evaluates next period.
+                        ps.ValueRW.LastProcessedTick = TickUtil.NonZero(now);
+                        ps.ValueRW.NextTick = TickUtil.NonZero(now + (uint)period);
+                    }
+                }
+
+                int res = 0, cnt = 0;
+                if (SystemAPI.IsComponentEnabled<ConveyorItem>(e))
+                {
+                    var item = SystemAPI.GetComponent<ConveyorItem>(e);
+                    if (item.Count > 0)
+                    {
+                        res = item.ResourceId;
+                        cnt = item.Count;
+                    }
+                }
+
+                convEntity.Add(e);
+                convCell.Add(ps.ValueRO.Cell);
+                convDir.Add(conveyor.ValueRO.Direction);
+                convItemRes.Add(res);
+                convItemCnt.Add(cnt);
+                convDue.Add(due);
+            }
+
+            int n = convEntity.Length;
+
+            // Cell → conveyor snapshot index (belt occupancy map for ResolveMoves + the pull lookup).
+            var cellToIndex = new NativeHashMap<int2, int>(n, Allocator.Temp);
+            for (int i = 0; i < n; i++)
+                cellToIndex.TryAdd(convCell[i], i); // duplicate cells can't occur (one structure per cell)
+
+            // Sink cells = cells hosting a machine-input buffer (fabricators); these always accept a deposit. Map
+            // each sink cell to its owning entity so an arriving item can be deposited into its MachineInput.
+            var sinkCells = new NativeHashSet<int2>(8, Allocator.Temp);
+            var sinkCellToEntity = new NativeHashMap<int2, Entity>(8, Allocator.Temp);
+            foreach (var (ps, _, e) in
+                     SystemAPI.Query<RefRO<PlacedStructure>, DynamicBuffer<MachineInput>>().WithEntityAccess())
+            {
+                sinkCells.Add(ps.ValueRO.Cell);
+                sinkCellToEntity.TryAdd(ps.ValueRO.Cell, e);
+            }
+
+            // Source cells = cells hosting a machine-OUTPUT buffer (harvesters/fabricators) a belt can pull from.
+            // Built once so the pull phase is a single hash lookup per belt (no nested per-belt query).
+            var outputCellToEntity = new NativeHashMap<int2, Entity>(8, Allocator.Temp);
+            foreach (var (ps, _, e) in
+                     SystemAPI.Query<RefRO<PlacedStructure>, DynamicBuffer<MachineOutput>>().WithEntityAccess())
+            {
+                outputCellToEntity.TryAdd(ps.ValueRO.Cell, e);
+            }
+
+            // ---- PULL: each empty, due belt draws one item off an adjacent UPSTREAM MachineOutput ----
+            // Upstream cell = myCell − DirOffset(dir): the machine feeding INTO this belt sits there. We pull a
+            // single unit so a harvester's buffered output flows onto the belt one item per period.
+            for (int i = 0; i < n; i++)
+            {
+                if (!convDue[i] || convItemCnt[i] > 0)
+                    continue;
+
+                int2 srcCell = convCell[i] - ConveyorMath.DirOffset(convDir[i]);
+
+                // The feeder must be a machine with a MachineOutput buffer (harvester or fabricator), NOT another
+                // conveyor (belts hand off in the move phase, not via pull). Single hash lookup on the prebuilt map.
+                if (!outputCellToEntity.TryGetValue(srcCell, out var feeder))
+                    continue;
+
+                var output = SystemAPI.GetBuffer<MachineOutput>(feeder);
+                // Pull the first available resource row off the feeder (deterministic: first non-empty row order).
+                byte pulledId = 0;
+                for (int r = 0; r < output.Length; r++)
+                {
+                    if (output[r].ResourceId != 0 && output[r].Count > 0)
+                    {
+                        pulledId = output[r].ResourceId;
+                        break;
+                    }
+                }
+                if (pulledId == 0)
+                    continue;
+
+                int taken = MachineSlotMath.Withdraw(output, pulledId, 1);
+                if (taken <= 0)
+                    continue;
+
+                // Load the belt in the snapshot so it participates in THIS tick's move resolution.
+                convItemRes[i] = pulledId;
+                convItemCnt[i] = taken;
+            }
+
+            // ---- MOVE: resolve all belt advances from the pre-move (post-pull) snapshot, then apply ----
+            var srcCells = new NativeArray<int2>(n, Allocator.Temp);
+            var dirs = new NativeArray<byte>(n, Allocator.Temp);
+            var itemRes = new NativeArray<int>(n, Allocator.Temp);
+            var itemCnt = new NativeArray<int>(n, Allocator.Temp);
+            for (int i = 0; i < n; i++)
+            {
+                srcCells[i] = convCell[i];
+                dirs[i] = convDir[i];
+                // Pass the FULL post-pull occupancy (due AND non-due) so the resolver blocks a due belt from moving
+                // INTO an occupied non-due cell. Non-due belts must still not ADVANCE themselves — that is enforced
+                // after resolution by skipping any returned move whose source belt is not due this tick.
+                itemRes[i] = convItemRes[i];
+                itemCnt[i] = convItemCnt[i];
+            }
+
+            var outMoveDst = new NativeArray<int2>(n, Allocator.Temp);
+            var outMoveSrcIdx = new NativeArray<int>(n, Allocator.Temp);
+            ConveyorMath.ResolveMoves(
+                srcCells, dirs, itemRes, itemCnt,
+                cellToIndex, sinkCells,
+                outMoveDst, outMoveSrcIdx, out int moveCount);
+
+            // Track which belts END this tick holding an item so we can settle enableable bits exactly once.
+            var endRes = new NativeArray<int>(n, Allocator.Temp);
+            var endCnt = new NativeArray<int>(n, Allocator.Temp);
+            for (int i = 0; i < n; i++)
+            {
+                // Default: every snapshot item stays put (stalls / non-due / no valid move). Moves below override.
+                endRes[i] = convItemRes[i];
+                endCnt[i] = convItemCnt[i];
+            }
+
+            for (int m = 0; m < moveCount; m++)
+            {
+                int srcIdx = outMoveSrcIdx[m];
+
+                // A non-due belt contributes its occupancy to the snapshot (so due belts can't overrun it) but must
+                // NOT advance its own item — skip its move and leave its item parked (the endRes/endCnt defaults).
+                if (!convDue[srcIdx])
+                    continue;
+
+                int2 dst = outMoveDst[m];
+                int movRes = convItemRes[srcIdx];
+                int movCnt = convItemCnt[srcIdx];
+
+                // The source belt empties (its item left this cell).
+                endRes[srcIdx] = 0;
+                endCnt[srcIdx] = 0;
+
+                if (sinkCells.Contains(dst))
+                {
+                    // Item leaves the belt network into a machine input slot.
+                    if (sinkCellToEntity.TryGetValue(dst, out var sinkEntity))
+                    {
+                        var input = SystemAPI.GetBuffer<MachineInput>(sinkEntity);
+                        MachineSlotMath.Deposit(input, (byte)movRes, movCnt);
+                    }
+                }
+                else if (cellToIndex.TryGetValue(dst, out int dstIdx))
+                {
+                    // Item advances onto the next belt cell (resolver guaranteed it was empty in the snapshot).
+                    endRes[dstIdx] = movRes;
+                    endCnt[dstIdx] = movCnt;
+                }
+            }
+
+            // ---- Settle each conveyor's ConveyorItem to its end-of-tick state (single write per belt) ----
+            for (int i = 0; i < n; i++)
+            {
+                var e = convEntity[i];
+                if (endCnt[i] > 0)
+                {
+                    SystemAPI.SetComponent(e, new ConveyorItem { ResourceId = (byte)endRes[i], Count = endCnt[i] });
+                    SystemAPI.SetComponentEnabled<ConveyorItem>(e, true);
+                }
+                else
+                {
+                    SystemAPI.SetComponent(e, new ConveyorItem { ResourceId = 0, Count = 0 });
+                    SystemAPI.SetComponentEnabled<ConveyorItem>(e, false);
+                }
+            }
+
+            convEntity.Dispose();
+            convCell.Dispose();
+            convDir.Dispose();
+            convItemRes.Dispose();
+            convItemCnt.Dispose();
+            convDue.Dispose();
+            cellToIndex.Dispose();
+            sinkCells.Dispose();
+            sinkCellToEntity.Dispose();
+            outputCellToEntity.Dispose();
+            srcCells.Dispose();
+            dirs.Dispose();
+            itemRes.Dispose();
+            itemCnt.Dispose();
+            outMoveDst.Dispose();
+            outMoveSrcIdx.Dispose();
+            endRes.Dispose();
+            endCnt.Dispose();
+        }
+    }
+}
@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 002c28988137cb945b9ffaccbb6d645f
@@ -0,0 +1,99 @@
+using ProjectM.Simulation;
+using Unity.Burst;
+using Unity.Entities;
+using Unity.Mathematics;
+using Unity.NetCode;
+
+namespace ProjectM.Server
+{
+    /// <summary>
+    /// Server-only, deterministic fabricator production — the BACK of the M7 auto-gather chain
+    /// (Harvester → Conveyor → Fabricator). Each <see cref="Fabricator"/> consumes
+    /// <see cref="Fabricator.InAmount"/> of its (byte) input resource from its OWN server-only
+    /// <see cref="MachineInput"/> buffer (filled by an upstream conveyor) and, on a
+    /// <see cref="Fabricator.PeriodTicks"/> cadence, deposits <see cref="Fabricator.OutAmount"/> of its output
+    /// resource into the GLOBAL ledger — so a self-running base compounds its stockpile. Resolves the ledger via
+    /// <c>GetSingletonEntity&lt;ResourceLedger&gt;()</c> → <c>GetBuffer&lt;StorageEntry&gt;()</c> (NEVER
+    /// <c>GetSingleton&lt;StorageEntry&gt;</c> — a second StorageEntry buffer exists on the base container).
+    /// Mirrors <c>TurretFireSystem</c>'s now-extraction + cooldown idiom and <c>ResourceHarvestSystem</c>'s ledger
+    /// resolve; runs in the plain server <c>SimulationSystemGroup</c>
+    /// <c>[UpdateAfter(ConveyorTransportSystem)]</c> (which itself is after the harvester + the predicted group),
+    /// so a single tick can harvest → transport → fabricate in chain order. In-place buffer/ledger mutation
+    /// (not structural) → no ECB.
+    /// <para>
+    /// SINGLE GATED CATCH-UP PATH, INPUT-LIMITED (no mint-from-nothing): when due, the awarded
+    /// <see cref="ProductionMath.CyclesDue"/> cycles are further clamped to what the buffered input can afford
+    /// (<c>floor(TotalOf(input,InResourceId)/InAmount)</c>). The tick fields are re-stamped EVERY due period
+    /// regardless of <c>runs</c> (even a starved fabricator advances its baseline so it re-evaluates next period,
+    /// not on the next tick — preventing a busy retry storm). Offline catch-up is within-session tick math; never
+    /// wall-clock.
+    /// </para>
+    /// </summary>
+    [BurstCompile]
+    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation)]
+    [UpdateInGroup(typeof(SimulationSystemGroup))]
+    [UpdateAfter(typeof(ConveyorTransportSystem))]
+    public partial struct FabricatorProductionSystem : ISystem
+    {
+        [BurstCompile]
+        public void OnCreate(ref SystemState state)
+        {
+            state.RequireForUpdate<NetworkTime>();
+            state.RequireForUpdate<ResourceLedger>();
+            state.RequireForUpdate(state.GetEntityQuery(ComponentType.ReadOnly<Fabricator>()));
+        }
+
+        [BurstCompile]
+        public void OnUpdate(ref SystemState state)
+        {
+            var serverTick = SystemAPI.GetSingleton<NetworkTime>().ServerTick;
+            if (!serverTick.IsValid)
+                return;
+            uint now = serverTick.TickIndexForValidTick;
+
+            var ledgerEntity = SystemAPI.GetSingletonEntity<ResourceLedger>();
+            var ledger = SystemAPI.GetBuffer<StorageEntry>(ledgerEntity);
+
+            foreach (var (ps, fab, input) in
+                     SystemAPI.Query<RefRW<PlacedStructure>, RefRO<Fabricator>, DynamicBuffer<MachineInput>>())
+            {
+                int period = fab.ValueRO.PeriodTicks; // CyclesDue clamps to max(1, period)
+
+                // Never-processed (baked/just-placed) machine: initialise the catch-up baseline, produce nothing.
+                if (ProductionMath.NeedsInit(ps.ValueRO.LastProcessedTick))
+                {
+                    ps.ValueRW.LastProcessedTick = TickUtil.NonZero(now);
+                    ps.ValueRW.NextTick = TickUtil.NonZero(now + (uint)System.Math.Max(1, period));
+                    continue;
+                }
+
+                int cycles = ProductionMath.CyclesDue(
+                    serverTick, ps.ValueRO.NextTick, ps.ValueRO.LastProcessedTick, period, Tuning.MaxProductionCatchup);
+                if (cycles <= 0)
+                    continue; // still cooling down / nothing due
+
+                byte inId = fab.ValueRO.InResourceId;
+                int inAmount = fab.ValueRO.InAmount;
+
+                // Input-limited: never produce more than the buffered input affords (no mint-from-nothing). A
+                // zero/negative recipe input amount is treated as unsatisfiable rather than dividing by zero.
+                int affordable = inAmount > 0
+                    ? MachineSlotMath.TotalOf(input, inId) / inAmount
+                    : 0;
+                int runs = math.min(cycles, affordable);
+
+                if (runs > 0)
+                {
+                    MachineSlotMath.Withdraw(input, inId, inAmount * runs);
+                    StorageMath.Deposit(ledger, (ushort)fab.ValueRO.OutResourceId, fab.ValueRO.OutAmount * runs);
+                }
+
+                // Re-stamp every due period regardless of runs (starved fabricators re-evaluate next period, not
+                // every tick) so the catch-up baseline never silently rewinds.
+                uint p = (uint)System.Math.Max(1, period);
+                ps.ValueRW.LastProcessedTick = TickUtil.NonZero(now);
+                ps.ValueRW.NextTick = TickUtil.NonZero(now + p);
+            }
+        }
+    }
+}
@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 1d8dbf02b41c9a94ea57fd7ca00f266d
@@ -0,0 +1,76 @@
+using ProjectM.Simulation;
+using Unity.Burst;
+using Unity.Entities;
+using Unity.NetCode;
+
+namespace ProjectM.Server
+{
+    /// <summary>
+    /// Server-only, deterministic harvester production — the FRONT of the M7 auto-gather chain
+    /// (Harvester → Conveyor → Fabricator). Each <see cref="Harvester"/> machine is a fixed-yield generator:
+    /// every <see cref="Harvester.PeriodTicks"/> server ticks it deposits <see cref="Harvester.Yield"/> of its
+    /// configured (byte) resource into its OWN server-only <see cref="MachineOutput"/> buffer (NOT the global
+    /// ledger — a conveyor pulls it onward, or it sits buffered). Mirrors <c>TurretFireSystem</c>'s exact
+    /// now-extraction (<c>NetworkTime.ServerTick.TickIndexForValidTick</c>) + <see cref="PlacedStructure.NextTick"/>
+    /// cooldown idiom, and runs in the plain server <c>SimulationSystemGroup</c>
+    /// <c>[UpdateAfter(PredictedSimulationSystemGroup)]</c> (the predicted group is OrderFirst → UpdateBefore is
+    /// ignored). Production mutates a DynamicBuffer in place (not a structural change) → no ECB needed.
+    /// <para>
+    /// SINGLE GATED CATCH-UP PATH (offline-quit safe, NO wall-clock minting): a never-processed machine
+    /// (LastProcessedTick==0) is initialised this tick and produces nothing; otherwise
+    /// <see cref="ProductionMath.CyclesDue"/> awards <c>floor((now-LastProcessedTick)/period)</c> cycles, clamped
+    /// to <see cref="Tuning.MaxProductionCatchup"/>, and the tick fields are re-stamped. All catch-up is
+    /// WITHIN-SESSION tick math; the stockpile is preserved across quit by the persistence layer, never re-minted
+    /// from a saved wall-clock.
+    /// </para>
+    /// </summary>
+    [BurstCompile]
+    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation)]
+    [UpdateInGroup(typeof(SimulationSystemGroup))]
+    [UpdateAfter(typeof(PredictedSimulationSystemGroup))]
+    public partial struct HarvesterProductionSystem : ISystem
+    {
+        [BurstCompile]
+        public void OnCreate(ref SystemState state)
+        {
+            state.RequireForUpdate<NetworkTime>();
+            state.RequireForUpdate(state.GetEntityQuery(ComponentType.ReadOnly<Harvester>()));
+        }
+
+        [BurstCompile]
+        public void OnUpdate(ref SystemState state)
+        {
+            var serverTick = SystemAPI.GetSingleton<NetworkTime>().ServerTick;
+            if (!serverTick.IsValid)
+                return;
+            uint now = serverTick.TickIndexForValidTick;
+
+            foreach (var (ps, harvester, output) in
+                     SystemAPI.Query<RefRW<PlacedStructure>, RefRO<Harvester>, DynamicBuffer<MachineOutput>>())
+            {
+                int period = harvester.ValueRO.PeriodTicks; // CyclesDue clamps to max(1, period)
+
+                // Never-processed (baked/just-placed) machine: initialise the catch-up baseline, produce nothing.
+                if (ProductionMath.NeedsInit(ps.ValueRO.LastProcessedTick))
+                {
+                    ps.ValueRW.LastProcessedTick = TickUtil.NonZero(now);
+                    ps.ValueRW.NextTick = TickUtil.NonZero(now + (uint)System.Math.Max(1, period));
+                    continue;
+                }
+
+                int cycles = ProductionMath.CyclesDue(
+                    serverTick, ps.ValueRO.NextTick, ps.ValueRO.LastProcessedTick, period, Tuning.MaxProductionCatchup);
+                if (cycles <= 0)
+                    continue; // still cooling down / nothing due
+
+                // Fixed-yield generation into the machine's own output slot (byte id; ledger conversion happens
+                // only at the global-ledger boundary, which this machine never crosses directly).
+                MachineSlotMath.Deposit(output, harvester.ValueRO.ResourceId, harvester.ValueRO.Yield * cycles);
+
+                uint p = (uint)System.Math.Max(1, period);
+                ps.ValueRW.LastProcessedTick = TickUtil.NonZero(now);
+                ps.ValueRW.NextTick = TickUtil.NonZero(now + p);
+            }
+        }
+    }
+}
@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: c484cb2331137134888f10eed7689140
@@ -23,11 +23,13 @@ namespace ProjectM.Server
    public partial struct BuildPlaceSystem : ISystem
    {
        ComponentLookup<LocalTransform> m_TransformLookup;
+        ComponentLookup<Conveyor> m_ConveyorLookup;

        [BurstCompile]
        public void OnCreate(ref SystemState state)
        {
            m_TransformLookup = state.GetComponentLookup<LocalTransform>(isReadOnly: true);
+            m_ConveyorLookup = state.GetComponentLookup<Conveyor>(isReadOnly: true);
            state.RequireForUpdate<StructureCatalog>();
            state.RequireForUpdate<BaseAnchor>();
            state.RequireForUpdate<ResourceLedger>();
@@ -41,6 +43,7 @@ namespace ProjectM.Server
        public void OnUpdate(ref SystemState state)
        {
            m_TransformLookup.Update(ref state);
+            m_ConveyorLookup.Update(ref state);
            uint now = SystemAPI.GetSingleton<NetworkTime>().ServerTick.TickIndexForValidTick;
            var anchor = SystemAPI.GetSingleton<BaseAnchor>();

@@ -88,9 +91,16 @@ namespace ProjectM.Server
                            Type = req.StructureType,
                            Cell = cell,
                            NextTick = 0u,
-                            LastProcessedTick = TickUtil.NonZero(now),
+                            LastProcessedTick = 0u, // 0 = uninitialized; the production systems set the baseline on first encounter (turret ignores it)
                        });
                        ecb.AddComponent(structure, new RegionTag { Region = RegionId.Base });
+                        ecb.AddComponent<RuntimePlacedTag>(structure); // player-built -> persisted by SaveStructureScan
+                        if (req.StructureType == StructureType.Conveyor && m_ConveyorLookup.HasComponent(entry.Prefab))
+                        {
+                            var conv = m_ConveyorLookup[entry.Prefab];
+                            conv.Direction = req.Direction;
+                            ecb.SetComponent(structure, conv);
+                        }
                    }
                }