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Source/VoxelForge/Public/VoxelGenerator.h

@@ -11,12 +11,14 @@
 #include "CoreMinimal.h"
 #include "VoxelTypes.h"
 #include "VoxelStrateTypes.h"
+#include "VoxelBiomeTypes.h"
 #include "VoxelGenerator.generated.h"
 
 // Forward decls (évite les includes transitifs)
 class UVoxelSettings;
 class UVoxelStrateManager;
 class UVoxelDiffLayer;
+class UVoxelBiomeDefinition;
 
 /**
  * UVoxelGenerator
@@ -103,9 +105,18 @@ public:
     /**
      * Densité pour une strate SurfaceWorld — terrain à ciel ouvert (collines,
      * montagnes, plages) sous un plafond solide, avec nappe d'eau optionnelle.
+     *
+     * Biome output-blend: the heightfield is evaluated with ParamsD (the voxel's dominant
+     * biome) and, when NeighborWeight > 0, also with ParamsN (its nearest neighbour); the
+     * two surface HEIGHTS are lerped. This stays seamless across ANY param difference
+     * (frequencies included). With no biomes, pass ParamsD == ParamsN and weight 0 →
+     * bit-identical to the single-param terrain. Structural fields (Z bounds, seal, base,
+     * water level) must be equal in both (forced from the strate).
      */
     float GetSurfaceDensity(float WorldX, float WorldY, float WorldZ,
-                            const FSurfaceGenerationParams& Params) const;
+                            const FSurfaceGenerationParams& ParamsD,
+                            const FSurfaceGenerationParams& ParamsN,
+                            float NeighborWeight) const;
 
     /**
      * Densité pour une strate VerticalShafts — puits verticaux pleine hauteur,
@@ -120,4 +131,67 @@ public:
      */
     float GetFloatingIslandDensity(float WorldX, float WorldY, float WorldZ,
                                    const FFloatingIslandParams& Params) const;
+
+    //=========================================================================
+    // CLIMATE & BIOME FIELDS  (pure XY, deterministic, window-invariant)
+    //=========================================================================
+
+    /**
+     * Relief ("elevation") field at a world XY → [0,1], contrast-shaped & smoothed.
+     * The single source of truth for the relief map M: SurfaceWorld terrain and the
+     * biome climate map both call this, so they agree when given the same freq/contrast.
+     */
+    float SampleRelief(float WorldX, float WorldY, float Frequency, float Contrast) const;
+
+    /**
+     * Moisture field at a world XY → [0,1]. The second climate axis for biome placement.
+     */
+    float SampleMoisture(float WorldX, float WorldY, float Frequency) const;
+
+    /**
+     * Resolve the biome at a world XY: dominant cell + nearest neighbour + blend weight.
+     * Warped Voronoi over a jittered grid; each cell's biome is chosen by its site's
+     * (relief, moisture) against the context's climate boxes. PURE function of (XY, seed,
+     * Ctx) — no chunk-window dependence (CODEMAP §8.4). Returns an empty sample when the
+     * context has no biomes. Used by the 2D preview bake and (next) the density path.
+     */
+    FBiomeSample SampleBiomeAt(float WorldX, float WorldY, const FBiomeContext& Ctx) const;
+
+    /**
+     * Hot-path biome resolve: the dominant + neighbour biome and blend weight at a world
+     * XY for the given strate slice. Uses (and lazily rebuilds) Cache — a box-validated
+     * per-chunk grid — so the noise-heavy cell classification happens once per chunk, not
+     * per voxel. Bit-identical to SampleBiomeAt, so the baked preview matches the terrain.
+     */
+    FBiomeSample ResolveBiomeSampleAt(float WorldX, float WorldY, int32 ChunkZ,
+                                      const FBiomeContext& Ctx, FChunkBiomeCache& Cache) const;
+
+    /**
+     * Dominant biome ASSET at a world XY for the given strate slice (chunk Z), or nullptr
+     * when the strate has no biomes / the point is outside the strate range. Game-thread
+     * helper for content + atmosphere selection — uses the same field as the density path.
+     */
+    const UVoxelBiomeDefinition* GetDominantBiomeAt(float WorldX, float WorldY, int32 ChunkZ) const;
+
+private:
+    /** Pick the biome (index into Ctx.Biomes) for a Voronoi site, by its climate. */
+    int32 ClassifyBiomeAtSite(float SiteX, float SiteY, const FBiomeContext& Ctx, uint32 SiteHash) const;
+
+    /** The SurfaceWorld heightfield: world XY → terrain surface Z (voxel coords). Pure
+     *  per-XY; the part that's evaluated per biome and blended in GetSurfaceDensity. */
+    float ComputeSurfaceTerrainZ(float WorldX, float WorldY, const FSurfaceGenerationParams& Params) const;
+
+    /** The SurfaceWorld sky-cap ceiling surface Z at a world XY (also pure per-XY). */
+    float ComputeSurfaceCeiling(float WorldX, float WorldY, const FSurfaceGenerationParams& Params) const;
+
+    /** Final SurfaceWorld density from a column's precomputed terrain Z + ceiling: the
+     *  cheap per-voxel Z-combine + origin spine + boundary seal + passage carving. The
+     *  XY-only work (terrain/ceiling) is done once per column and cached (T1.a). */
+    float SurfaceDensityFromColumn(float WorldX, float WorldY, float WorldZ,
+                                   float TerrainZ, float CeilSurf,
+                                   const FSurfaceGenerationParams& Structural) const;
+
+    /** (Re)build the per-chunk biome cell grid covering chunk (X,Y) footprint + margin. */
+    void RebuildBiomeGrid(int32 ChunkX, int32 ChunkY, int32 ChunkZ,
+                          const FBiomeContext& Ctx, FChunkBiomeCache& Cache) const;
 };