46544ef3c1
User report: trees that exist in retail are missing in ACdream. SceneryGenerator had an extra heuristic filter at lines 169-180 that rejected scenery whose cell-origin vertex was a road vertex, on top of the proper retail post-displacement road check (FUN_00530d30 port via IsOnRoad). The comment admitted it wasn't in the retail decomp -- it was added to widen road margins visually. Side effect: any cell whose SW corner happened to touch a road vertex had ALL of its scenery dropped, even when the displaced position was well clear of the road ribbon. Removing the extra guard. The retail FUN_00530d30 ribbon test already handles road exclusion correctly; the heuristic was strictly subtractive and silently dropped trees the retail client renders. Tests stay 1439 green. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
431 lines
21 KiB
C#
431 lines
21 KiB
C#
using System.Numerics;
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using DatReaderWriter;
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using DatReaderWriter.DBObjs;
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using DatReaderWriter.Types;
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namespace AcDream.Core.World;
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/// <summary>
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/// Procedural scenery placement for a landblock. AC encodes "sparse decoration"
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/// (trees, bushes, rocks, fences, small props) NOT as explicit Stab entries on
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/// the LandBlockInfo but as per-terrain-vertex Scene/ObjectDesc references in
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/// the Region dat, placed pseudo-randomly via deterministic LCG math keyed on
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/// the vertex's global cell coordinates. Without this generator, any landblock
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/// rendered from dats is missing all of its natural scenery.
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///
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/// Algorithm verified against the decompiled retail acclient.exe (Ghidra output):
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/// - Scene-selection hash: chunk_00530000.c line 1144
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/// - Per-object frequency: chunk_00530000.c lines 1168-1174
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/// - Displacement formula: chunk_005A0000.c lines 4858-4878 (FUN_005a6cc0)
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/// - Quadrant rotation: chunk_005A0000.c lines 4880-4902
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/// - Object rotation hash: chunk_005A0000.c lines 4924-4926 (FUN_005a6e60)
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/// - Object scale: ACViewer Physics/Common/ObjectDesc.cs ScaleObj()
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/// (scale hash constant 0x7f51=32593 not in dumped chunks;
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/// confirmed against ACViewer which matches all other constants)
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///
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/// Key implementation note: the decompiled client computes each LCG value as a
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/// signed 32-bit int, then normalises with "if (val < 0) val += 2^32" before
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/// dividing by 2^32. This is equivalent to our unchecked((uint)(...)) cast.
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/// ACViewer's reference omits this cast and is subtly wrong for negative inputs.
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/// We deliberately match the decompiled client, not ACViewer.
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///
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/// We deliberately skip the slope/road/building-overlap checks the original does;
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/// those prevent scenery from floating in roads or clipping buildings but
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/// require walkable-polygon lookups that we don't yet have. Accepting visual
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/// artifacts (trees inside roads, scenery clipping buildings) for a first pass
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/// and deferring the filters to a later phase.
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/// </summary>
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public static class SceneryGenerator
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{
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// AC landblock geometry — matches LandblockMesh.
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private const int VerticesPerSide = 9;
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private const float CellSize = 24.0f;
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private const float LandblockSize = 192.0f; // 8 cells * 24 units
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public readonly record struct ScenerySpawn(
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uint ObjectId, // GfxObj or Setup id
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Vector3 LocalPosition, // landblock-local world units
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Quaternion Rotation,
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float Scale);
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/// <summary>
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/// Generate all scenery entries for one landblock. Uses the bit-packed
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/// TerrainInfo Type (bits 2-6) and Scenery (bits 11-15) fields to index into
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/// Region.TerrainInfo.TerrainTypes[type].SceneTypes[scenery] → a SceneInfo
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/// index into Region.SceneInfo.SceneTypes[sceneInfo].Scenes. Each cell picks
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/// one scene via a pseudo-random hash of the cell's global coordinates, then
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/// iterates the scene's ObjectDesc entries with per-object frequency rolls.
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/// </summary>
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public static IReadOnlyList<ScenerySpawn> Generate(
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DatCollection dats,
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Region region,
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LandBlock block,
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uint landblockId,
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HashSet<int>? buildingCells = null,
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float[]? heightTable = null)
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{
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var result = new List<ScenerySpawn>();
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if (region.TerrainInfo?.TerrainTypes is null || region.SceneInfo?.SceneTypes is null)
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return result;
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uint blockX = (landblockId >> 24) * 8; // 8 cells per landblock
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uint blockY = ((landblockId >> 16) & 0xFFu) * 8;
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// RETAIL iterates 8×8 = 64 CELLS, not 9×9 = 81 vertices.
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// Decompiled FUN_005311a0 at chunk_00530000.c:1123-1253 uses
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// `while (local_94 < 8)` and `while (local_8c < 8)` — bound by
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// `param_1+0x40` which is SideCellCount=8 for outdoor landblocks.
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// The terrain word at each cell's SW corner drives that cell's scenery.
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for (int x = 0; x < CellsPerSide; x++)
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{
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for (int y = 0; y < CellsPerSide; y++)
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{
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int i = x * VerticesPerSide + y;
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ushort raw = block.Terrain[i];
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uint terrainType = (uint)((raw >> 2) & 0x1F); // bits 2-6
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uint sceneType = (uint)((raw >> 11) & 0x1F); // bits 11-15
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// NOTE: retail does NOT skip based on this vertex's road bit.
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// The road test happens AFTER displacement via the 4-corner
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// polygonal OnRoad check (see below). Removing the
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// pre-displacement early-exit restores retail behavior.
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// Skip cells that contain buildings.
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if (buildingCells is not null && buildingCells.Contains(i)) continue;
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if (terrainType >= region.TerrainInfo.TerrainTypes.Count) continue;
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var sceneTypeList = region.TerrainInfo.TerrainTypes[(int)terrainType].SceneTypes;
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if (sceneType >= sceneTypeList.Count) continue;
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uint sceneInfo = sceneTypeList[(int)sceneType];
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if (sceneInfo >= region.SceneInfo.SceneTypes.Count) continue;
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var scenes = region.SceneInfo.SceneTypes[(int)sceneInfo].Scenes;
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if (scenes.Count == 0) continue;
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uint cellX = (uint)x;
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uint cellY = (uint)y;
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uint globalCellX = cellX + blockX;
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uint globalCellY = cellY + blockY;
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// Scene-selection hash: picks one scene from the terrain's scene list.
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// Decompiled: chunk_00530000.c line 1144
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// iVar5 = (iVar8 * 0x2a7f2b89 + 0x6c1ac587) * iVar9 + iVar8 * -0x421be3bd + 0x7f8cda01
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// where iVar8=globalCellX, iVar9=globalCellY.
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uint cellMat = globalCellY * (712977289u * globalCellX + 1813693831u)
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- 1109124029u * globalCellX + 2139937281u;
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double offset = cellMat * 2.3283064e-10;
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int sceneIdx = (int)(scenes.Count * offset);
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if (sceneIdx >= scenes.Count || sceneIdx < 0) sceneIdx = 0;
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uint sceneId = (uint)scenes[sceneIdx];
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var scene = dats.Get<Scene>(sceneId);
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if (scene is null) continue;
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// Per-object hashes: roll frequency, compute displacement, scale, rotation.
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// Decompiled: chunk_00530000.c lines 1168-1174
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// iStack_60 = iVar9 * 0x6c1ac587 → cellYMat
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// uStack_78 = iVar9 * iVar8 * 0x5111bfef + 0x70892fb7 → cellMat2
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// iStack_64 = iVar8 * -0x421be3bd → cellXMat
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// initial: local_90 = uStack_78 * 0x5b67 (j=0 term)
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// per-loop: iStack_70 = (iStack_60 - local_90) + iStack_64; local_90 += uStack_78
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// ⟹ iStack_70 = cellYMat - cellMat2 * (0x5b67 + j) + cellXMat
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uint cellXMat = unchecked(0u - 1109124029u * globalCellX);
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uint cellYMat = 1813693831u * globalCellY;
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uint cellMat2 = 1360117743u * globalCellX * globalCellY + 1888038839u;
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for (uint j = 0; j < scene.Objects.Count; j++)
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{
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var obj = scene.Objects[(int)j];
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if (obj.WeenieObj != 0) continue; // Weenie entries are dynamic spawns, not static scenery
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// Frequency roll: chunk_00530000.c line 1174 + 1179
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// (fVar1 * _DAT_007c6f10 < (float)piVar11[0x11]) → noise < obj.Frequency
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double noise = unchecked((uint)(cellXMat + cellYMat - cellMat2 * (23399u + j))) * 2.3283064e-10;
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if (noise >= obj.Frequency) continue;
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// Displacement: pseudo-random offset within the cell.
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var localPos = DisplaceObject(obj, globalCellX, globalCellY, j);
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float lx = cellX * CellSize + localPos.X;
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float ly = cellY * CellSize + localPos.Y;
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if (lx < 0 || ly < 0 || lx >= LandblockSize || ly >= LandblockSize)
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continue;
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// Retail post-displacement road check (FUN_00530d30).
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// Ported from ACViewer Landblock.OnRoad — uses the 4-corner
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// road bits of the containing cell plus the 5-unit road
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// half-width to test whether the displaced (lx,ly) lies on
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// the road ribbon.
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bool isOnRoad = IsOnRoad(block, lx, ly);
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if (isOnRoad)
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{
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continue;
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}
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// L-fix2 (2026-04-28): the extra cell-origin road-vertex
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// guard previously here is REMOVED. It wasn't in the
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// retail decomp — it was a heuristic added to widen
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// road margins visually. The proper retail post-
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// displacement road check (FUN_00530d30 port via
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// IsOnRoad above) already handles road exclusion.
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// The extra guard was over-suppressing — every cell
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// whose SW corner happened to touch a road vertex
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// had ALL of its scenery dropped, even when the
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// displaced position was well clear of the ribbon.
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// User reported missing trees they could see in
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// retail; this is the most likely cause.
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// Slope filter (ACME conformance fix 4e): compute terrain normal
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// Z-component at the displaced position and check against the
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// object's MinSlope/MaxSlope bounds.
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if (heightTable is not null && (obj.MinSlope > 0f || obj.MaxSlope < 1f))
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{
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int sx = Math.Clamp((int)(lx / CellSize), 0, VerticesPerSide - 2);
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int sy = Math.Clamp((int)(ly / CellSize), 0, VerticesPerSide - 2);
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int sxR = sx + 1;
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int syU = sy + 1;
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float h00 = heightTable[block.Height[sx * VerticesPerSide + sy]];
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float h10 = heightTable[block.Height[sxR * VerticesPerSide + sy]];
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float h01 = heightTable[block.Height[sx * VerticesPerSide + syU]];
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float dx = (h10 - h00) / CellSize;
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float dy = (h01 - h00) / CellSize;
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float nz = 1f / MathF.Sqrt(dx * dx + dy * dy + 1f); // normal Z component
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if (nz < obj.MinSlope || nz > obj.MaxSlope) continue;
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}
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// BaseLoc.Z offset: scenery-specific vertical offset from
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// the ground (e.g., flowers planted at -0.1m so they
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// don't float above grass). The renderer adds groundZ
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// later, so pass the BaseLoc.Z through as-is.
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float lz = obj.BaseLoc.Origin.Z;
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// Rotation: chunk_005A0000.c lines 4924-4931 (FUN_005a6e60)
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// Retail calls FUN_00425f10(baseLoc) to copy baseLoc.Orientation
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// into the frame, THEN calls AFrame::set_heading(degrees).
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//
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// set_heading uses yaw = -(450 - heading) % 360 before converting
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// to a quaternion, which introduces a 90° offset + sign flip
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// relative to a naive Z rotation. WorldBuilder's
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// SceneryHelpers.SetHeading reproduces this.
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//
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// For objects with Align != 0, retail uses FUN_005a6f60 to
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// align to the landcell polygon's normal instead of setting
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// heading from the noise.
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//
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// Composition: final = baseLoc.Orientation * headingQuat
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Quaternion rotation = obj.BaseLoc.Orientation;
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if (rotation.LengthSquared() < 0.0001f)
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rotation = Quaternion.Identity;
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if (obj.MaxRotation > 0f)
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{
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double rotNoise = unchecked((uint)(1813693831u * globalCellY
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- (j + 63127u) * (1360117743u * globalCellY * globalCellX + 1888038839u)
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- 1109124029u * globalCellX)) * 2.3283064e-10;
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float degrees = (float)(rotNoise * obj.MaxRotation);
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// AFrame::set_heading transform — matches retail.
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float yawDeg = -((450f - degrees) % 360f);
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float yawRad = yawDeg * MathF.PI / 180f;
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var headingQuat = Quaternion.CreateFromAxisAngle(Vector3.UnitZ, yawRad);
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rotation = headingQuat * rotation;
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}
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// Scale: ACViewer Physics/Common/ObjectDesc.cs ScaleObj() (confirmed matches pattern)
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// offset constant 0x7f51 = 32593 (not in dumped chunks; cross-verified via ACViewer)
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// same LCG structure as rotation/displacement; uint cast per decompiled normalisation
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float scale;
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if (obj.MinScale == obj.MaxScale)
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{
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scale = obj.MaxScale;
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}
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else
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{
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double scaleNoise = unchecked((uint)(1813693831u * globalCellY
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- (j + 32593u) * (1360117743u * globalCellY * globalCellX + 1888038839u)
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- 1109124029u * globalCellX)) * 2.3283064e-10;
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scale = (float)(Math.Pow(obj.MaxScale / obj.MinScale, scaleNoise) * obj.MinScale);
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}
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if (scale <= 0) scale = 1f;
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result.Add(new ScenerySpawn(
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ObjectId: obj.ObjectId,
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LocalPosition: new Vector3(lx, ly, lz),
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Rotation: rotation,
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Scale: scale));
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}
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}
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}
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return result;
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}
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/// <summary>
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/// Returns true if the raw terrain word indicates a road vertex.
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/// Bits 0-1 of the terrain word encode the road type; any non-zero value
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/// means the vertex is on a road. Ported from ACViewer GetRoad().
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/// </summary>
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public static bool IsRoadVertex(ushort raw) => (raw & 0x3u) != 0;
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/// <summary>
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/// Half-width of a road ribbon in world units — the road extends from each
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/// road vertex by this amount into the neighbor cells. Matches retail's
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/// `_DAT_007c9cc0 = 5.0f` in FUN_00530d30.
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/// </summary>
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private const float RoadHalfWidth = 5.0f;
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/// <summary>
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/// Retail-faithful post-displacement road test. Ported from ACViewer
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/// Landblock.OnRoad (Physics/Common/Landblock.cs lines 300-398), which is
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/// a direct port of FUN_00530d30 in the retail client.
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///
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/// Examines the 4 corners of the cell containing (lx, ly) and, depending
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/// on how many are road vertices (0, 1, 2, 3, or 4), applies a polygonal
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/// test using the 5-unit road half-width to check if (lx, ly) lies on the
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/// road ribbon. Returns true if the point is on a road.
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/// </summary>
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/// <summary>
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/// Retail-faithful road ribbon test — direct port of ACViewer's
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/// Landblock.OnRoad (Physics/Common/Landblock.cs lines 300-398), which
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/// itself is a port of FUN_00530d30 in acclient.exe.
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///
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/// Classifies the 4 corners of the cell containing (lx, ly) by road type
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/// (bits 0-1 of the terrain word) and applies a different geometric test
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/// based on which corners are road vertices. Road ribbons have a 5m
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/// half-width (TileLength - RoadWidth = 19m).
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/// </summary>
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private static bool IsOnRoad(LandBlock block, float lx, float ly)
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{
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int x = (int)MathF.Floor(lx / CellSize);
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int y = (int)MathF.Floor(ly / CellSize);
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// Clamp so we don't index past the 9x9 terrain grid
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x = Math.Clamp(x, 0, CellsPerSide - 1);
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y = Math.Clamp(y, 0, CellsPerSide - 1);
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float rMin = RoadHalfWidth; // 5
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float rMax = CellSize - RoadHalfWidth; // 19
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// Corner road bits (ACViewer convention):
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// r0 = (x0, y0) = SW
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// r1 = (x0, y1) = NW
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// r2 = (x1, y0) = SE
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// r3 = (x1, y1) = NE
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bool r0 = IsRoadVertex(block.Terrain[x * VerticesPerSide + y]);
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bool r1 = IsRoadVertex(block.Terrain[x * VerticesPerSide + (y + 1)]);
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bool r2 = IsRoadVertex(block.Terrain[(x + 1) * VerticesPerSide + y]);
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bool r3 = IsRoadVertex(block.Terrain[(x + 1) * VerticesPerSide + (y + 1)]);
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if (!r0 && !r1 && !r2 && !r3) return false;
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float dx = lx - x * CellSize;
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float dy = ly - y * CellSize;
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if (r0)
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{
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if (r1)
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{
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if (r2)
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{
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if (r3) return true;
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return dx < rMin || dy < rMin;
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}
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else
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{
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if (r3) return dx < rMin || dy > rMax;
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return dx < rMin;
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}
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}
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else
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{
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if (r2)
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{
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if (r3) return dx > rMax || dy < rMin;
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return dy < rMin;
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}
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else
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{
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if (r3) return MathF.Abs(dx - dy) < rMin;
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return dx + dy < rMin;
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}
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}
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}
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else
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{
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if (r1)
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{
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if (r2)
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{
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if (r3) return dx > rMax || dy > rMax;
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return MathF.Abs(dx + dy - CellSize) < rMin;
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}
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else
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{
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if (r3) return dy > rMax;
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return CellSize + dx - dy < rMin;
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}
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}
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else
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{
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if (r2)
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{
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if (r3) return dx > rMax;
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return CellSize - dx + dy < rMin;
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}
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else
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{
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if (r3) return CellSize * 2f - dx - dy < rMin;
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return false;
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}
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}
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}
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}
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private const int CellsPerSide = 8;
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/// <summary>
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/// Pseudo-random displacement within a cell for a scenery object. Returns a
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/// Vector3 in local cell-offset space (the caller adds it to the cell corner
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/// to get landblock-local position).
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///
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/// Verified against decompiled acclient.exe: chunk_005A0000.c lines 4844-4903 (FUN_005a6cc0).
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/// X offset constant 0xb2cd = 45773; Y offset constant 0x11c0f = 72719.
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/// Quadrant hash: line 4880; thresholds 0.25/0.5/0.75 map to _DAT_007c97cc/_DAT_007938b8/_DAT_0079c6dc.
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/// Decompiled normalises signed-int LCG results with "if (val < 0) val += 2^32"; our
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/// unchecked((uint)(...)) is exactly equivalent.
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/// </summary>
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private static Vector3 DisplaceObject(ObjectDesc obj, uint ix, uint iy, uint iq)
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{
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float x, y;
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var baseLoc = obj.BaseLoc.Origin;
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// X displacement: chunk_005A0000.c lines 4858-4866
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// iVar4 = (param_3 * 0x6c1ac587 - (param_2 * param_3 * 0x5111bfef + 0x70892fb7) * (param_4 + 0xb2cd)) + param_2 * -0x421be3bd
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if (obj.DisplaceX <= 0)
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x = baseLoc.X;
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else
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x = (float)(unchecked((uint)(1813693831u * iy - (iq + 45773u) * (1360117743u * iy * ix + 1888038839u) - 1109124029u * ix))
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* 2.3283064e-10 * obj.DisplaceX + baseLoc.X);
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// Y displacement: chunk_005A0000.c lines 4871-4878 (same structure, offset 0x11c0f = 72719)
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if (obj.DisplaceY <= 0)
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y = baseLoc.Y;
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else
|
||
y = (float)(unchecked((uint)(1813693831u * iy - (iq + 72719u) * (1360117743u * iy * ix + 1888038839u) - 1109124029u * ix))
|
||
* 2.3283064e-10 * obj.DisplaceY + baseLoc.Y);
|
||
|
||
float z = baseLoc.Z;
|
||
|
||
// Quadrant selection: chunk_005A0000.c lines 4880-4902
|
||
// iVar4 = (param_3 * 0x6c1ac587 - (param_3 * 0x6f7bd965 + 0x421be3bd) * param_2) + -0x17fcedfd
|
||
// 0x6f7bd965=1870387557, 0x421be3bd=1109124029, -0x17fcedfd → -402451965 (uint: 3892515331)
|
||
double quadrant = unchecked((uint)(1813693831u * iy - ix * (1870387557u * iy + 1109124029u) - 402451965u)) * 2.3283064e-10;
|
||
|
||
if (quadrant >= 0.75) return new Vector3(y, -x, z);
|
||
if (quadrant >= 0.5) return new Vector3(-x, -y, z);
|
||
if (quadrant >= 0.25) return new Vector3(-y, x, z);
|
||
return new Vector3(x, y, z);
|
||
}
|
||
}
|