feat(vf): add EndIsland and ObsidianPillar

core/include/vf/EndGen.h

@@ -0,0 +1,105 @@
+#pragma once
+
+#include <cstdint>
+#include <vector>
+
+#include "Noise.h"
+#include "NoiseAdv.h"
+#include "World.h"
+
+namespace vf {
+
+enum class EndBiome : uint8_t {
+    Void = 0,
+    CentralIsland = 1,
+    OuterIsland = 2,
+    Count,
+};
+
+// A lens of end stone floating in the void. `thickness` is the half-depth at
+// the island centre; it tapers to nothing at the rim.
+struct EndIsland {
+    Vec3i center;
+    float radius = 0.0f;
+    float thickness = 0.0f;
+    bool central = false;
+
+    bool valid() const { return radius > 0.0f; }
+};
+
+struct ObsidianPillar {
+    Vec3i base;
+    int radius = 1;
+    int height = 0;
+    bool crowned = false;
+};
+
+// Deterministic End generator: one central end stone island ringed by void,
+// an outer island belt beyond a distance threshold, obsidian pillars on a
+// fixed ring around the origin, a bedrock exit portal at the centre and
+// recursive chorus growth on the outer islands.
+class EndGenerator {
+public:
+    struct Params {
+        uint32_t seed = 1337u;
+        int floorY = 0;
+        int ceilingY = 128;
+        int islandY = 52;
+        float centralRadius = 88.0f;
+        float centralThickness = 24.0f;
+        float edgeFrequency = 0.017f;
+        float edgeAmplitude = 15.0f;
+        int outerDistance = 640;
+        int outerCellSize = 160;
+        int outerChance = 3;
+        int pillarCount = 10;
+        int pillarRing = 43;
+        bool chorus = true;
+        bool exitPortal = true;
+    };
+
+    EndGenerator();
+    explicit EndGenerator(const Params& endParams);
+
+    const Params& settings() const { return params; }
+    int stackChunkCount() const { return (params.ceilingY - params.floorY) / chunkSize; }
+
+    EndBiome biomeAt(int gx, int gz) const;
+    EndIsland islandAt(int gx, int gz) const;
+
+    bool isVoid(int gx, int gz) const;
+    // Top end stone block of the column, or floorY - 1 when the column is void.
+    int surfaceHeight(int gx, int gz) const;
+    bool isStone(int gx, int gy, int gz) const;
+
+    std::vector<ObsidianPillar> pillars() const;
+
+    void generateChunk(Chunk& chunk, const Vec3i& chunkCoord) const;
+    void generateColumn(World& world, int columnX, int columnZ) const;
+    void decorateColumn(World& world, int columnX, int columnZ) const;
+
+    // Recursive chorus stem. Each level grows one to three vertical segments,
+    // sprouts up to two side branches that recurse on their own, and caps
+    // every dead end with a flower. Returns the number of blocks written.
+    int growChorus(World& world, const Vec3i& base, uint32_t roll, int maxDepth) const;
+
+    void placePillars(World& world) const;
+    void placeExitPortal(World& world) const;
+
+private:
+    EndIsland centralIsland() const;
+    EndIsland outerIslandFor(int cellX, int cellZ) const;
+    bool columnExtent(int gx, int gz, int& topY, int& bottomY) const;
+
+    int growBranch(World& world, Vec3i pos, int depth, int maxDepth, uint32_t& rngState) const;
+    void stampPillars(World& world, int minX, int minZ, int maxX, int maxZ) const;
+    void stampExitPortal(World& world, int minX, int minZ, int maxX, int maxZ) const;
+    void raisePurpurSpire(World& world, int gx, int gz, int top, uint32_t roll) const;
+
+    Params params;
+    PerlinNoise edgeNoise;
+    PerlinNoise surfaceNoise;
+    NoiseAdv outerNoise;
+};
+
+} // namespace vf