#pragma once

// ============================================================================
// terrain.h - 程序化地形
// ============================================================================

#include <d3d11.h>
#include "../Rendering/mesh.h"

#define TERRAIN_MAX_HEIGHTMAP_SIZE 256

typedef struct {
    float* data;
    int size;
} TerrainHeightmap;

typedef struct {
    int chunks_x;
    int chunks_z;
    int vertices_per_chunk;
    float chunk_size;
    float height_scale;
    float uv_scale;
} TerrainConfig;

typedef struct {
    TerrainConfig config;
    TerrainHeightmap heightmap;
    Mesh* mesh;
    ID3D11Device* device;
} Terrain;

// 默认配置
TerrainConfig terrain_default_config(void);

// 高度图
TerrainHeightmap terrain_heightmap_create(int size);
void terrain_heightmap_destroy(TerrainHeightmap* hm);
void terrain_heightmap_fill_noise(TerrainHeightmap* hm, int seed, float scale, float amplitude);
float terrain_heightmap_sample(const TerrainHeightmap* hm, float x, float z);

// 地形对象
Terrain* terrain_create(ID3D11Device* dev, const TerrainConfig* config);
void terrain_destroy(Terrain* terrain);

// 从世界坐标采样高度 (用于相机/角色贴地)
float terrain_get_height(const Terrain* terrain, float world_x, float world_z);

// 网格生成
Mesh* terrain_mesh_create(ID3D11Device* dev, const TerrainHeightmap* hm, float size, float height_scale, float uv_scale);

// 噪声工具（供分块管理器复用）
float hash_noise(int x, int z, int seed);
float fbm_noise(float x, float z, int seed, int octaves, float persistence);