Upload spectrum ring slots by offset

docs/implementation-plan.md

@@ -156,9 +156,11 @@ a named invariant that the native runtime cannot protect yet.
   truncated and reported in the runtime UI. Lowerings use that fixed capacity
   as `ColumnStride`. Physical history slots are addressed as a ring with
   `RollingOffset`, so logical age no longer requires reshuffling every column
-  before shader sampling. `MIMIR_SPECTRUM_TUBE_SUBDIVISIONS` controls the
-  requested Catmull-Rom subdivision count so Fensalir's overflow report has a
-  direct cost lever.
+  before shader sampling. Mimir emits one Float32 resource upload per sampled
+  history slot with an explicit element offset, rather than uploading the full
+  fixed-capacity backing buffer every frame. `MIMIR_SPECTRUM_TUBE_SUBDIVISIONS`
+  controls the requested Catmull-Rom subdivision count so Fensalir's overflow
+  report has a direct cost lever.
 - `MimirFensalirFieldLowering` now emits `AquariumFieldResourceDeclaration`
   rows for live native/GPU payload views. Observation claims reference
   `mimir:resource:*` keys, and Fensalir validation/planning can reject or defer

notes/current-system-map.md

@@ -393,9 +393,11 @@ resize the GPU buffer while the rolling trail fills. `MIMIR_SPECTRUM_SOURCE_LANE
 sets the fixed lane budget; surplus sources are truncated and reported in the
 runtime UI. Physical history slots are now addressed as a ring with
 `RollingOffset`, so logical age no longer requires moving every column before
-shader sampling. `MIMIR_SPECTRUM_TUBE_SUBDIVISIONS` is the runtime cost lever
-for lowering Catmull-Rom subdivision count when Fensalir reports TubeField
-truncation.
+shader sampling. Mimir emits one Float32 resource upload per sampled history
+slot with an explicit element offset instead of uploading the full
+fixed-capacity backing buffer every frame. `MIMIR_SPECTRUM_TUBE_SUBDIVISIONS`
+is the runtime cost lever for lowering Catmull-Rom subdivision count when
+Fensalir reports TubeField truncation.
 
 ## Known Risks
 

src/Mimir.BufferSmoke/Program.cs

@@ -655,8 +655,9 @@ static int RunMimirSpectrumUploadSmoke()
 
         var frame = runtime.Frame;
         var field = frame.Scene.FieldEvidenceFrame;
-        var upload = field.ResourceUploads.SingleOrDefault(upload =>
-            string.Equals(upload.ResourceKey, "mimir:resource:spectrum:field-upload", StringComparison.Ordinal));
+        var matchingUploads = field.ResourceUploads
+            .Where(upload => string.Equals(upload.ResourceKey, "mimir:resource:spectrum:field-upload", StringComparison.Ordinal))
+            .ToArray();
         var matchingResources = field.Resources
             .Where(resource => string.Equals(resource.ResourceKey, "mimir:resource:spectrum:field-upload", StringComparison.Ordinal))
             .ToArray();
@@ -686,19 +687,30 @@ static int RunMimirSpectrumUploadSmoke()
             .ToArray();
 
         Console.WriteLine(
-            $"mimir-spectrum-upload-smoke resources={field.Resources.Count} uploads={field.ResourceUploads.Count} claims={field.Claims.Count} tubeLowerings={field.TubeSplineLowerings.Count} planned={plan.Packets.Count} errors={validation.HasErrors} legacySplines={frame.Scene.SplineFrame.Splines.Count} bufferFields={frame.Scene.BufferFieldFrame.SplineTubeFields.Count + frame.Scene.BufferFieldFrame.TextureSplineFields.Count} uploadFloats={upload?.Float32Data.Count ?? 0}");
+            $"mimir-spectrum-upload-smoke resources={field.Resources.Count} uploads={field.ResourceUploads.Count} claims={field.Claims.Count} tubeLowerings={field.TubeSplineLowerings.Count} planned={plan.Packets.Count} errors={validation.HasErrors} legacySplines={frame.Scene.SplineFrame.Splines.Count} bufferFields={frame.Scene.BufferFieldFrame.SplineTubeFields.Count + frame.Scene.BufferFieldFrame.TextureSplineFields.Count} uploadFloats={matchingUploads.Sum(upload => upload.Float32Data.Count)}");
 
         return
             !validation.HasErrors &&
             !frame.Scene.SplineFrame.HasInput &&
             !frame.Scene.BufferFieldFrame.HasInput &&
-            upload is not null &&
+            matchingUploads.Length == expectedHistoryCount &&
             matchingResources.Length == 1 &&
             matchingRamps.Length == 1 &&
             matchingLowerings.Length == 4 &&
             matchingClaims.Length == matchingLowerings.Length &&
-            upload.Version == resource.Version &&
-            upload.Float32Data.Count == resource.DepthOrCount &&
+            matchingUploads.All(upload => upload.Version == resource.Version) &&
+            matchingUploads.Sum(upload => upload.Float32Data.Count) == lowering.Width * expectedSourceLaneCapacity * expectedHistoryCount &&
+            matchingUploads.All(upload =>
+                upload.Float32Data.Count == lowering.Width * expectedSourceLaneCapacity &&
+                upload.ElementOffset >= 0 &&
+                upload.ElementOffset + upload.Float32Data.Count <= resource.DepthOrCount) &&
+            matchingUploads.Select(upload => upload.ElementOffset).Order().SequenceEqual(
+                new[]
+                {
+                    0,
+                    lowering.Width * expectedSourceLaneCapacity * (expectedHistoryCapacity - 2),
+                    lowering.Width * expectedSourceLaneCapacity * (expectedHistoryCapacity - 1),
+                }.Order()) &&
             resource.Kind == AquariumFieldResourceKind.StructuredBuffer &&
             resource.Residency == AquariumFieldResourceResidency.GpuResident &&
             resource.Access == AquariumFieldShaderAccess.ShaderResource &&
@@ -710,7 +722,6 @@ static int RunMimirSpectrumUploadSmoke()
             string.Equals(ramp.Format, "Rgba8Unorm", StringComparison.OrdinalIgnoreCase) &&
             string.Equals(ramp.SourceUri, @"D:\WIP4\Projects\Aetheria\Assets\Resources\Ramps\blackbody.png", StringComparison.OrdinalIgnoreCase) &&
             resource.Height == expectedSourceLaneCapacity * expectedHistoryCapacity &&
-            lowering.Width * resource.Height == upload.Float32Data.Count &&
             matchingLowerings.All(item =>
                 item.ColumnCount == expectedHistoryCount &&
                 item.ColumnStride == expectedSourceLaneCapacity &&

src/Mimir.Runtime/MimirRuntime.cs

@@ -280,10 +280,12 @@ public sealed class MimirRuntime : IAquariumRuntime
         var resourceColumnCapacity = checked(spectrumSourceLaneCapacity * SpectrumHistoryWindowCount);
         var newestHistorySlot = PositiveModulo(-historyFrames[0].Sequence, SpectrumHistoryWindowCount);
         var rollingOffset = checked(newestHistorySlot * spectrumSourceLaneCapacity);
-        var samples = new float[width * resourceColumnCapacity];
+        var resourceUploads = new List<AquariumFieldResourceUpload>(historyFrames.Length);
         for (var historyIndex = 0; historyIndex < historyFrames.Length; historyIndex++)
         {
             var historySlot = PositiveModulo(-historyFrames[historyIndex].Sequence, SpectrumHistoryWindowCount);
+            var uploadColumnOffset = checked(historySlot * spectrumSourceLaneCapacity);
+            var samples = new float[width * spectrumSourceLaneCapacity];
             foreach (var spectrum in historyFrames[historyIndex].Spectra)
             {
                 if (!sourceIndexById.TryGetValue(spectrum.SourceId, out var sourceIndex))
@@ -291,9 +293,16 @@ public sealed class MimirRuntime : IAquariumRuntime
                     continue;
                 }
 
-                var physicalColumn = historySlot * spectrumSourceLaneCapacity + sourceIndex;
-                WriteNormalizedSpectrum(spectrum, samples.AsSpan(physicalColumn * width, width));
+                WriteNormalizedSpectrum(spectrum, samples.AsSpan(sourceIndex * width, width));
             }
+
+            resourceUploads.Add(new AquariumFieldResourceUpload
+            {
+                ResourceKey = SpectrumFieldResourceKey,
+                Version = unchecked((ulong)Math.Max(0, spectrumHistorySequence)),
+                ElementOffset = checked(uploadColumnOffset * width),
+                Float32Data = samples,
+            });
         }
 
         const string domainKey = "mimir:domain:spectrum:field-upload";
@@ -323,7 +332,7 @@ public sealed class MimirRuntime : IAquariumRuntime
             Format: "Float32",
             Width: width,
             Height: resourceColumnCapacity,
-            DepthOrCount: samples.Length,
+            DepthOrCount: checked(width * resourceColumnCapacity),
             StrideBytes: sizeof(float),
             ValidFromNs: 0,
             ValidUntilNs: 0,
@@ -422,12 +431,7 @@ public sealed class MimirRuntime : IAquariumRuntime
             ResourceUploads =
             [
                 .. frame.ResourceUploads,
-                new AquariumFieldResourceUpload
-                {
-                    ResourceKey = SpectrumFieldResourceKey,
-                    Version = version,
-                    Float32Data = samples,
-                },
+                .. resourceUploads,
             ],
             TubeSplineLowerings = [.. frame.TubeSplineLowerings, .. lowerings],
             AccumulationWindowSeconds = frame.AccumulationWindowSeconds,

state/evidence.jsonl

@@ -167,3 +167,4 @@
 {"ts": "2026-05-27T11:41:00+01:00", "type": "implementation", "status": "ok", "note": "Mimir now exposes MIMIR_SPECTRUM_TUBE_SUBDIVISIONS as the first runtime cost lever for TubeField overflow. The spectrum upload smoke sets it to 2 and verifies every emitted source-lane TubeSpline lowering uses that Catmull-Rom subdivision count, so Fensalir's requested/dispatched/truncated segment report can be answered without changing code."}
 {"ts": "2026-05-27T11:47:48+01:00", "type": "implementation", "status": "ok", "note": "Mimir spectrum upload now has fixed source-lane capacity as well as fixed history capacity. MIMIR_SPECTRUM_SOURCE_LANES sets the lane budget, TubeSpline lowerings use that budget as ColumnStride, surplus sources are truncated and reported in the runtime UI, and --mimir-spectrum-upload-smoke verifies 48 bands x 8 lanes x 40 history capacity = 15360 uploaded floats while emitting only four active TubeField claims/lowerings."}
 {"ts": "2026-05-27T11:54:44+01:00", "type": "implementation", "status": "ok", "note": "Mimir spectrum history now uses true ring addressing. Physical history slots are keyed by sequence modulo the fixed history capacity, TubeSpline lowerings carry RollingOffset for newest logical age, and --mimir-spectrum-upload-smoke verifies the expected offset with the fixed 8-lane resource. This makes partial column uploads possible without changing shader sampling semantics."}
+{"ts": "2026-05-27T12:00:41+01:00", "type": "implementation", "status": "ok", "note": "Mimir now emits partial spectrum resource uploads for the active ring slots it samples. The declared GPU buffer remains fixed at 48 bands x 8 lanes x 40 history slots, but the smoke now verifies three offset uploads totaling 1152 floats for the three active ages instead of a full 15360-float backing-store upload. Headless Fensalir rendered the offset-copy path with empty stderr."}

state/map.yaml

@@ -372,9 +372,12 @@ accepted_design:
     shared Float32 resource so each active lane renders a true age trail at
     `z = age * 0.1`. Physical history slots are addressed as a ring with
     `RollingOffset`, so logical age no longer requires moving every column in
-    the upload matrix before shader sampling. `MIMIR_SPECTRUM_TUBE_SUBDIVISIONS`
-    controls the Mimir-requested Catmull-Rom subdivisions so Fensalir's
-    TubeField truncation report has a direct cost lever.
+    the upload matrix before shader sampling. Mimir emits one Float32 resource
+    upload per sampled history slot with an explicit element offset instead of
+    uploading the full fixed-capacity backing buffer every frame.
+    `MIMIR_SPECTRUM_TUBE_SUBDIVISIONS` controls the Mimir-requested Catmull-Rom
+    subdivisions so Fensalir's TubeField truncation report has a direct cost
+    lever.
   - `config/perfect-machine.example.json` declares live owners, sensors,
     reservoir views, and runtime policy.
   - `src/Mimir.Runtime/Synchronization` now includes the Perfect Machine module