diff --git a/Core/Scripts/BlueprintFormat.cs b/Core/Scripts/BlueprintFormat.cs
index 75ca496..38e591a 100644
--- a/Core/Scripts/BlueprintFormat.cs
+++ b/Core/Scripts/BlueprintFormat.cs
@@ -43,11 +43,13 @@ namespace IslaApocalypse.Core
// differently shaped payload into plausible-looking nonsense.
public const ushort TDTL_VERSION = 2;
- // EROS body version (terrain-water task 17). 1 = the droplet hydraulic-
- // erosion params block: governors (count/lifetime/carve cap), sea clamp,
- // brush, strength constants, RNG seed offset, crater exclusion factor.
- // Same reader rule as TDTL: an unknown body version is skipped whole.
- public const ushort EROS_VERSION = 1;
+ // EROS body version. 1 (task 17) = governors count/lifetime/carve cap, sea
+ // clamp, brush, strength constants, RNG seed offset, crater exclusion factor;
+ // the only v1 payloads in existence are in that task's batch tree. 2 (task 18,
+ // current) inserts the DEPOSIT CAP governor after the carve cap — deposition is
+ // now brush-spread and per-cell bounded. Same reader rule as TDTL: an unknown
+ // body version is skipped whole rather than misread into plausible nonsense.
+ public const ushort EROS_VERSION = 2;
// WSRF quantization: u16, 0 reserved as the no-water sentinel. A real level L
// (raw blueprint height units) encodes as 1 + round(L × 32768), so a genuine
diff --git a/Core/Scripts/BlueprintWriter.cs b/Core/Scripts/BlueprintWriter.cs
index 4a9e339..fa4c43f 100644
--- a/Core/Scripts/BlueprintWriter.cs
+++ b/Core/Scripts/BlueprintWriter.cs
@@ -170,7 +170,8 @@ namespace IslaApocalypse.Core
writer.Write(e.Version); // u16
writer.Write(e.DropletCount); writer.Write(e.Lifetime); // 2 × i32
writer.Write(e.BrushRadius); writer.Write(e.SeedOffset); // 2 × i32
- writer.Write(e.CarveCapM); writer.Write(e.SeaMarginM); // 2 × f32
+ writer.Write(e.CarveCapM); writer.Write(e.DepositCapM); // 2 × f32
+ writer.Write(e.SeaMarginM); // f32
writer.Write(e.Inertia); writer.Write(e.CapacityFactor); // 2 × f32
writer.Write(e.MinSlopeM); // f32
writer.Write(e.ErodeRate); writer.Write(e.DepositRate); // 2 × f32
diff --git a/Core/Scripts/ConfigManager.cs b/Core/Scripts/ConfigManager.cs
index d27bb1e..c7d696d 100644
--- a/Core/Scripts/ConfigManager.cs
+++ b/Core/Scripts/ConfigManager.cs
@@ -55,18 +55,28 @@ namespace IslaApocalypse.Core // Change this if your namespace is different
// never touched at all, so the rendered coastline cannot move. The remaining
// dials are the standard droplet-model strength constants; slopes/amounts
// are in METRES (1 raw height unit = 251 m).
+ // Task-18 defaults tune for a DRAINAGE HIERARCHY: long-lived, committed
+ // droplets (lifetime 384 at inertia 0.35, evaporation 0.004) travel far
+ // enough down a flank that their paths overlap and deepen shared low lines
+ // into trunk channels, instead of dying as independent 48-px scratches;
+ // the carve cap is raised to 15 m so trunks can separate from the fine
+ // rills instead of both piling up against the same ceiling. A modest
+ // erode rate keeps the total material moved in detailing range.
+ // ErosionDepositCap is governor 4 (task 18): brush-spread deposition alone
+ // does not bound a spike once droplets carry long-path loads.
public static string Erosion = "off";
- public static int ErosionDropletCount = 400000;
- public static int ErosionDropletLifetime = 48;
- public static float ErosionCarveCap = 8.0f; // m per cell
+ public static int ErosionDropletCount = 250000;
+ public static int ErosionDropletLifetime = 384;
+ public static float ErosionCarveCap = 15.0f; // m per cell
+ public static float ErosionDepositCap = 6.0f; // m per cell; <= 0 = unbounded
public static float ErosionSeaMargin = 0.5f; // m above sea, carve floor
public static int ErosionBrushRadius = 2; // px
- public static float ErosionInertia = 0.05f;
+ public static float ErosionInertia = 0.35f;
public static float ErosionCapacity = 4.0f;
- public static float ErosionMinSlope = 0.01f; // m per px, capacity floor
- public static float ErosionErodeRate = 0.3f;
- public static float ErosionDepositRate = 0.3f;
- public static float ErosionEvaporation = 0.02f;
+ public static float ErosionMinSlope = 0.02f; // m per px, capacity floor
+ public static float ErosionErodeRate = 0.12f;
+ public static float ErosionDepositRate = 0.15f;
+ public static float ErosionEvaporation = 0.004f;
public static float ErosionGravity = 4.0f;
// Island falloff shaping (task 11).
@@ -215,6 +225,7 @@ namespace IslaApocalypse.Core // Change this if your namespace is different
if (data.ContainsKey("ErosionDropletCount")) ErosionDropletCount = (int)data["ErosionDropletCount"];
if (data.ContainsKey("ErosionDropletLifetime")) ErosionDropletLifetime = (int)data["ErosionDropletLifetime"];
if (data.ContainsKey("ErosionCarveCap")) ErosionCarveCap = (float)data["ErosionCarveCap"];
+ if (data.ContainsKey("ErosionDepositCap")) ErosionDepositCap = (float)data["ErosionDepositCap"];
if (data.ContainsKey("ErosionSeaMargin")) ErosionSeaMargin = (float)data["ErosionSeaMargin"];
if (data.ContainsKey("ErosionBrushRadius")) ErosionBrushRadius = (int)data["ErosionBrushRadius"];
if (data.ContainsKey("ErosionInertia")) ErosionInertia = (float)data["ErosionInertia"];
@@ -235,6 +246,8 @@ namespace IslaApocalypse.Core // Change this if your namespace is different
ErosionCarveCap = Mathf.Clamp(ErosionCarveCap, 0f, 60f);
if (rawCount != ErosionDropletCount || rawLife != ErosionDropletLifetime || rawCap != ErosionCarveCap)
GD.PrintErr($"[ConfigManager] Erosion governor out of bounds — clamped: count {rawCount}->{ErosionDropletCount}, lifetime {rawLife}->{ErosionDropletLifetime}, cap {rawCap}->{ErosionCarveCap} m.");
+ // Negative is meaningless; 0 is the documented "unbounded" escape hatch.
+ ErosionDepositCap = Mathf.Clamp(ErosionDepositCap, 0f, 60f);
ErosionSeaMargin = Mathf.Clamp(ErosionSeaMargin, 0f, 5f);
ErosionBrushRadius = Mathf.Clamp(ErosionBrushRadius, 0, 8);
ErosionInertia = Mathf.Clamp(ErosionInertia, 0f, 0.99f);
diff --git a/Core/Scripts/MapDataParser.cs b/Core/Scripts/MapDataParser.cs
index f160a73..068028d 100644
--- a/Core/Scripts/MapDataParser.cs
+++ b/Core/Scripts/MapDataParser.cs
@@ -115,7 +115,7 @@ namespace IslaApocalypse.Core
{
public ushort Version;
public int DropletCount, Lifetime, BrushRadius, SeedOffset;
- public float CarveCapM, SeaMarginM;
+ public float CarveCapM, DepositCapM, SeaMarginM;
public float Inertia, CapacityFactor, MinSlopeM;
public float ErodeRate, DepositRate, Evaporation, Gravity;
public float CraterExclFactor;
@@ -509,7 +509,8 @@ namespace IslaApocalypse.Core
}
e.DropletCount = reader.ReadInt32(); e.Lifetime = reader.ReadInt32();
e.BrushRadius = reader.ReadInt32(); e.SeedOffset = reader.ReadInt32();
- e.CarveCapM = reader.ReadSingle(); e.SeaMarginM = reader.ReadSingle();
+ e.CarveCapM = reader.ReadSingle(); e.DepositCapM = reader.ReadSingle();
+ e.SeaMarginM = reader.ReadSingle();
e.Inertia = reader.ReadSingle(); e.CapacityFactor = reader.ReadSingle();
e.MinSlopeM = reader.ReadSingle();
e.ErodeRate = reader.ReadSingle(); e.DepositRate = reader.ReadSingle();
diff --git a/Tools/Scripts/HydraulicErosion.cs b/Tools/Scripts/HydraulicErosion.cs
index 9638723..4ff2877 100644
--- a/Tools/Scripts/HydraulicErosion.cs
+++ b/Tools/Scripts/HydraulicErosion.cs
@@ -10,7 +10,9 @@ using System;
/// then walks downhill with inertia, carrying water and sediment. Where the ground
/// is steep and it moves fast it ERODES (up to capacity, spread over a small brush
/// so no single-cell spikes — the anti-artifact that killed the D8 predecessor);
-/// where it flattens out it DEPOSITS, building valley floors and fans. Water
+/// where it flattens out it DEPOSITS, building valley floors and fans, over the
+/// SAME brush (task 18 — bilinear 4-cell deposition built isolated cones at gully
+/// mouths; carving and dumping are now symmetric). Water
/// evaporates each step; the droplet dies at its lifetime, at the map edge, or on
/// reaching the sea (its remaining sediment is lost to the ocean).
///
@@ -20,9 +22,16 @@ using System;
/// The three hard governors (the pass provably cannot run away):
/// 1. DropletCount — total droplets (the main detail/cost dial).
/// 2. Lifetime — max steps per droplet; no infinite wandering.
-/// 3. CarveCapM — max cumulative erosion depth per cell, in metres,
-/// enforced against a per-cell ledger. The runaway-trench
-/// guard, and what keeps this a DETAILING pass.
+/// 3. CarveCapM — max erosion depth per cell, in metres, measured from the
+/// height the pass found and enforced against a per-cell NET
+/// displacement ledger. The runaway-trench guard, and the
+/// dial that decides how deep trunk channels may cut.
+/// 4. DepositCapM — max build-up per cell, the same ledger read the other way
+/// (task 18). Brush-spreading alone does not bound a spike:
+/// droplets on long paths carry far more sediment, and a
+/// loaded droplet meeting a rise dumps min(rise, load) at
+/// once. This makes "no deposit cones" a governor rather
+/// than a hope. <= 0 disables it (the reference model).
///
/// The sea clamp (the "don't over-flood" guard): erosion never lowers any cell
/// below its local sea level + SeaMarginM, and cells already below sea are
@@ -40,7 +49,11 @@ using System;
///
public static class HydraulicErosion
{
- public const ushort VERSION = 1;
+ // The EROS body version is owned by the format (Core) and read from there, not
+ // restated here: the version byte IS the payload layout's identity, so a local
+ // copy that drifts writes a v2 body stamped v1 and every reader shifts a field.
+ // (Caught doing exactly that in task 18 — mirrors TerrainDetailPass.VERSION.)
+ public const ushort VERSION = IslaApocalypse.Core.BlueprintFormat.EROS_VERSION;
// Deterministic RNG stream: seeded from resolvedSeed + this offset, so a seed
// reproduces exactly and the stream is decorrelated from every noise field
@@ -68,6 +81,7 @@ public static class HydraulicErosion
public int DropletCount; // governor 1
public int Lifetime; // governor 2
public float CarveCapM; // governor 3 (metres)
+ public float DepositCapM; // governor 4 (metres); <= 0 = unbounded
public float SeaMarginM; // sea clamp margin (metres)
public int BrushRadius; // erosion brush radius, px
public float Inertia; // 0 = pure gradient descent, 1 = never turns
@@ -89,7 +103,8 @@ public static class HydraulicErosion
public double ErodedVolumeM3; // 1 px = 1 m², so metres of depth sum to m³
public double DepositedVolumeM3;
public float MaxCellErosionM; // must end ≤ CarveCapM
- public long ErodedCells; // cells with any net ledger erosion
+ public float MaxCellDepositM; // the deposit-spike metric (task 18)
+ public long ModifiedCells; // cells the pass touched at all
}
// PCG32 (O'Neill) — tiny, deterministic, trivially portable to C++.
@@ -122,8 +137,12 @@ public static class HydraulicErosion
float capUnits = p.CarveCapM / M_PER_UNIT;
if (p.DropletCount <= 0 || capUnits <= 0f) return stats;
- // Per-cell cumulative-erosion ledger — governor 3's enforcement record.
- float[,] eroded = new float[mapSize, mapSize];
+ // Per-cell NET displacement ledger, metres, positive = carved below where the
+ // pass found this cell, negative = built up above it. Governor 3's enforcement
+ // record: the cap bounds `net`, so it bounds erosion depth measured from the
+ // ORIGINAL height — deposit-then-carve at one cell cannot smuggle in extra
+ // depth, and carve-then-deposit correctly frees the headroom back up.
+ float[,] net = new float[mapSize, mapSize];
// Spawn weighting needs the seed's top height.
float hTop = float.MinValue;
@@ -227,18 +246,40 @@ public static class HydraulicErosion
if (dhM > 0f || sedimentM > capacityM)
{
// Moving uphill (fill the pit behind us, at most the rise) or
- // over capacity (drop a fraction of the surplus): DEPOSIT at
- // the OLD position, bilinear over its 4 cells.
+ // over capacity (drop a fraction of the surplus): DEPOSIT over
+ // the SAME cone brush erosion uses (task 18). Bilinear 4-cell
+ // deposition — the reference model's — concentrated a whole
+ // droplet's load into one cell at gully mouths and built
+ // isolated cones (measured 15.5 m on seed 1280587109, task 17
+ // §6.1). Spreading it makes deposition the symmetric mirror of
+ // carving; total mass is unchanged, only its footprint.
float amountM = dhM > 0f ? MathF.Min(dhM, sedimentM)
: (sedimentM - capacityM) * p.DepositRate;
if (amountM > 0f)
{
- float w00 = (1f - fx) * (1f - fy), w10 = fx * (1f - fy);
- float w01 = (1f - fx) * fy, w11 = fx * fy;
- sedimentM -= DepositCell(height, eroded, xi, yi, amountM * w00, stats, SeaAt, Excluded)
- + DepositCell(height, eroded, xi + 1, yi, amountM * w10, stats, SeaAt, Excluded)
- + DepositCell(height, eroded, xi, yi + 1, amountM * w01, stats, SeaAt, Excluded)
- + DepositCell(height, eroded, xi + 1, yi + 1, amountM * w11, stats, SeaAt, Excluded);
+ for (int b = 0; b < brushN; b++)
+ {
+ int cx = xi + brushDx[b], cy = yi + brushDy[b];
+ if (cx < 0 || cx >= mapSize || cy < 0 || cy >= mapSize) continue;
+ if (Excluded(cx, cy)) continue;
+ float hCell = height[cx, cy];
+ // Below-sea cells are read-only in BOTH directions: no
+ // submarine deltas, so the rendered coastline cannot move.
+ if (hCell < SeaAt(cx, cy)) continue;
+ float give = amountM * brushW[b];
+ // Governor 4: the ledger read the other way. net is negative
+ // where the cell has already been built up, so the headroom
+ // is cap + net.
+ if (p.DepositCapM > 0f)
+ give = MathF.Min(give, MathF.Max(0f, p.DepositCapM + net[cx, cy]));
+ if (give <= 0f) continue;
+ height[cx, cy] = hCell + give / M_PER_UNIT;
+ if (net[cx, cy] == 0f) stats.ModifiedCells++;
+ net[cx, cy] -= give;
+ if (-net[cx, cy] > stats.MaxCellDepositM) stats.MaxCellDepositM = -net[cx, cy];
+ sedimentM -= give;
+ stats.DepositedVolumeM3 += give;
+ }
}
}
else
@@ -258,13 +299,13 @@ public static class HydraulicErosion
if (hCell < sea) continue; // below-sea cells are read-only
float want = amountM * brushW[b];
float bySea = MathF.Max(0f, (hCell - (sea + p.SeaMarginM / M_PER_UNIT)) * M_PER_UNIT);
- float byCap = MathF.Max(0f, p.CarveCapM - eroded[cx, cy]);
+ float byCap = MathF.Max(0f, p.CarveCapM - net[cx, cy]);
float take = MathF.Min(want, MathF.Min(bySea, byCap));
if (take <= 0f) continue;
height[cx, cy] = hCell - take / M_PER_UNIT;
- if (eroded[cx, cy] == 0f) stats.ErodedCells++;
- eroded[cx, cy] += take;
- if (eroded[cx, cy] > stats.MaxCellErosionM) stats.MaxCellErosionM = eroded[cx, cy];
+ if (net[cx, cy] == 0f) stats.ModifiedCells++;
+ net[cx, cy] += take;
+ if (net[cx, cy] > stats.MaxCellErosionM) stats.MaxCellErosionM = net[cx, cy];
sedimentM += take;
stats.ErodedVolumeM3 += take;
}
@@ -284,27 +325,11 @@ public static class HydraulicErosion
if (stats.MaxCellErosionM > p.CarveCapM * (1f + 1e-5f))
throw new InvalidOperationException(
$"[HydraulicErosion] CARVE-CAP VIOLATION: a cell accumulated {stats.MaxCellErosionM} m against cap {p.CarveCapM} m. Refusing to generate.");
+ if (p.DepositCapM > 0f && stats.MaxCellDepositM > p.DepositCapM * (1f + 1e-5f))
+ throw new InvalidOperationException(
+ $"[HydraulicErosion] DEPOSIT-CAP VIOLATION: a cell built up {stats.MaxCellDepositM} m against cap {p.DepositCapM} m. Refusing to generate.");
return stats;
}
- ///
- /// Deposits up to metres on one cell; returns what was
- /// actually placed. Below-sea cells and crater-excluded cells take nothing —
- /// deposition only ever raises LAND, so the coastline cannot move and the sea
- /// cannot shallow. A cell's ledgered erosion is paid back first, so erode-then-
- /// deposit at one cell frees cap headroom instead of double-counting.
- ///
- private static float DepositCell(float[,] height, float[,] eroded, int cx, int cy,
- float amountM, Stats stats, Func seaAt, Func excluded)
- {
- if (amountM <= 0f) return 0f;
- float hCell = height[cx, cy];
- if (hCell < seaAt(cx, cy)) return 0f;
- if (excluded(cx, cy)) return 0f;
- height[cx, cy] = hCell + amountM / M_PER_UNIT;
- eroded[cx, cy] = MathF.Max(0f, eroded[cx, cy] - amountM);
- stats.DepositedVolumeM3 += amountM;
- return amountM;
- }
}
diff --git a/Tools/Scripts/HydraulicErosion.cs.uid b/Tools/Scripts/HydraulicErosion.cs.uid
new file mode 100644
index 0000000..5782d33
--- /dev/null
+++ b/Tools/Scripts/HydraulicErosion.cs.uid
@@ -0,0 +1 @@
+uid://hls3pvvnqci5
diff --git a/Tools/Scripts/MapGenerator.cs b/Tools/Scripts/MapGenerator.cs
index 0e2e1d8..bc34835 100644
--- a/Tools/Scripts/MapGenerator.cs
+++ b/Tools/Scripts/MapGenerator.cs
@@ -383,6 +383,7 @@ public partial class MapGenerator : TextureRect
BrushRadius = ConfigManager.ErosionBrushRadius,
SeedOffset = HydraulicErosion.SEED_OFFSET,
CarveCapM = ConfigManager.ErosionCarveCap,
+ DepositCapM = ConfigManager.ErosionDepositCap,
SeaMarginM = ConfigManager.ErosionSeaMargin,
Inertia = ConfigManager.ErosionInertia,
CapacityFactor = ConfigManager.ErosionCapacity,
@@ -706,6 +707,7 @@ public partial class MapGenerator : TextureRect
DropletCount = ConfigManager.ErosionDropletCount,
Lifetime = ConfigManager.ErosionDropletLifetime,
CarveCapM = ConfigManager.ErosionCarveCap,
+ DepositCapM = ConfigManager.ErosionDepositCap,
SeaMarginM = ConfigManager.ErosionSeaMargin,
BrushRadius = ConfigManager.ErosionBrushRadius,
Inertia = ConfigManager.ErosionInertia,
@@ -727,8 +729,9 @@ public partial class MapGenerator : TextureRect
$"[MapGenerator] EROSION FLOOD-GUARD VIOLATION: render-map water pixels {wetBefore} -> {wetAfter}. Refusing to generate.");
GD.Print($"{T()} [Erosion] v1: {st.Spawned} droplets ({st.SkippedNoLand} skipped), {st.Steps} steps, " +
- $"{(Time.GetTicksMsec() - tEro0) / 1000.0:F1}s wall. Eroded {st.ErodedVolumeM3:F0} m³ over {st.ErodedCells} cells " +
- $"(max cell {st.MaxCellErosionM:F2} m vs cap {p.CarveCapM:F2} m), deposited {st.DepositedVolumeM3:F0} m³. " +
+ $"{(Time.GetTicksMsec() - tEro0) / 1000.0:F1}s wall. Eroded {st.ErodedVolumeM3:F0} m³ over {st.ModifiedCells} touched cells " +
+ $"(max cell carve {st.MaxCellErosionM:F2} m vs cap {p.CarveCapM:F2} m), deposited {st.DepositedVolumeM3:F0} m³ " +
+ $"(max cell deposit {st.MaxCellDepositM:F2} m vs cap {p.DepositCapM:F2} m). " +
$"Deaths: {st.DiedSea} sea / {st.DiedEdge} edge / {st.DiedDry} dry / {st.DiedLifetime} lifetime. " +
$"Water pixels {wetBefore} -> {wetAfter} (flood guard holds).");
}
diff --git a/Tools/Scripts/RoundTripHarness.cs b/Tools/Scripts/RoundTripHarness.cs
index 078523e..846c954 100644
--- a/Tools/Scripts/RoundTripHarness.cs
+++ b/Tools/Scripts/RoundTripHarness.cs
@@ -258,9 +258,9 @@ public partial class RoundTripHarness : Node
bool same = ea.Version == eb.Version
&& ea.DropletCount == eb.DropletCount && ea.Lifetime == eb.Lifetime
&& ea.BrushRadius == eb.BrushRadius && ea.SeedOffset == eb.SeedOffset;
- float[] fa = { ea.CarveCapM, ea.SeaMarginM, ea.Inertia, ea.CapacityFactor, ea.MinSlopeM,
+ float[] fa = { ea.CarveCapM, ea.DepositCapM, ea.SeaMarginM, ea.Inertia, ea.CapacityFactor, ea.MinSlopeM,
ea.ErodeRate, ea.DepositRate, ea.Evaporation, ea.Gravity, ea.CraterExclFactor };
- float[] fb = { eb.CarveCapM, eb.SeaMarginM, eb.Inertia, eb.CapacityFactor, eb.MinSlopeM,
+ float[] fb = { eb.CarveCapM, eb.DepositCapM, eb.SeaMarginM, eb.Inertia, eb.CapacityFactor, eb.MinSlopeM,
eb.ErodeRate, eb.DepositRate, eb.Evaporation, eb.Gravity, eb.CraterExclFactor };
for (int i = 0; i < fa.Length; i++)
if (System.BitConverter.SingleToInt32Bits(fa[i]) != System.BitConverter.SingleToInt32Bits(fb[i])) same = false;