152 lines
5.2 KiB
C++
152 lines
5.2 KiB
C++
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#pragma once
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/**
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* @file topology_compression.h
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* @brief B-Rep 拓扑压缩 & Edgebreaker 三角网格压缩 & 顶点量化
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*
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* 三类压缩策略：
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* 1. B-Rep 拓扑压缩 — 将 BrepModel 的拓扑结构序列化为紧凑二进制格式
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* 2. Edgebreaker — 三角网格连通性无损压缩（CLERS 编码）
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* 3. 顶点坐标量化 — 将浮点坐标压入定点整数区间
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*
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* @ingroup core
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*/
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#include "vde/core/point.h"
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#include "vde/brep/brep.h"
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#include "vde/mesh/halfedge_mesh.h"
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#include <vector>
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#include <string>
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#include <cstdint>
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namespace vde::core {
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// ═══════════════════════════════════════════════════════════
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// B-Rep 拓扑压缩
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// ═══════════════════════════════════════════════════════════
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/**
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* @brief B-Rep 拓扑压缩结果
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*/
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struct BrepCompressed {
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std::vector<uint8_t> data; ///< 压缩二进制数据
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size_t body_count; ///< Body 数量
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size_t face_count; ///< Face 总数
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size_t edge_count; ///< Edge 总数
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size_t vertex_count; ///< Vertex 总数
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size_t original_bytes; ///< 原始估算字节数
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double compression_ratio; ///< 压缩比 (compressed/original)
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};
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/**
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* @brief 压缩 BrepModel 为紧凑二进制格式
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*
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* 将拓扑连接关系压入变长整数，几何数据独立存储。
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*
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* @param body BrepModel 引用
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* @return BrepCompressed 压缩结果
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* @ingroup core
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*/
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BrepCompressed compress_brep(const vde::brep::BrepModel& body);
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/**
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* @brief 解压为 BrepModel
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*
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* @param data 压缩数据
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* @return 重构的 BrepModel
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* @ingroup core
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*/
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vde::brep::BrepModel decompress_brep(const BrepCompressed& data);
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// ═══════════════════════════════════════════════════════════
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// Edgebreaker 三角网格压缩
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// ═══════════════════════════════════════════════════════════
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/// CLERS 操作码
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enum class EdgebreakerOp : uint8_t {
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C = 0, ///< C — 封闭边界环
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L = 1, ///< L — 左相邻面
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E = 2, ///< E — 对面顶点
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R = 3, ///< R — 右相邻面
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S = 4 ///< S — 分裂操作
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};
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/**
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* @brief Edgebreaker 压缩结果
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*/
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struct EdgebreakerResult {
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std::vector<EdgebreakerOp> clers; ///< CLERS 操作序列
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std::vector<int> vertices; ///< 解压所需顶点偏移（S/E 操作附参）
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size_t face_count; ///< 面数
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size_t vertex_count; ///< 顶点数
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};
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/**
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* @brief 使用 Edgebreaker 压缩三角网格连通性
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*
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* 输入网格的连通性（面索引），输出 CLERS 操作序列。
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* 仅压缩拓扑，不含几何坐标。
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*
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* @param mesh 三角网格
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* @return EdgebreakerResult
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* @ingroup core
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*/
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EdgebreakerResult edgebreaker_compress(const vde::mesh::HalfedgeMesh& mesh);
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/**
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* @brief Edgebreaker 解压
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*
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* 从 CLERS 序列重建三角网格连通性。
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*
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* @param result Edgebreaker 压缩结果
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* @return 重建的三角网格（仅拓扑，顶点坐标为占位）
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* @ingroup core
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*/
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vde::mesh::HalfedgeMesh edgebreaker_decompress(const EdgebreakerResult& result);
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// ═══════════════════════════════════════════════════════════
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// 顶点坐标量化压缩
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// ═══════════════════════════════════════════════════════════
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/// 量化模式
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enum class QuantMode {
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Uniform8, ///< 8 位均匀量化（每分量 1 字节）
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Uniform16, ///< 16 位均匀量化（每分量 2 字节）
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Uniform32, ///< 32 位均匀量化（每分量 4 字节）
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};
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/**
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* @brief 顶点量化结果
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*/
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struct VertexQuantResult {
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std::vector<uint8_t> data; ///< 量化后的字节数据
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Point3D bbox_min; ///< 包围盒最小点
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Point3D bbox_max; ///< 包围盒最大点
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QuantMode mode; ///< 量化模式
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size_t vertex_count; ///< 顶点数
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double max_error; ///< 最大量化误差
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double avg_error; ///< 平均量化误差
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};
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/**
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* @brief 顶点坐标量化压缩
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*
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* 将顶点坐标相对于包围盒的浮点值映射到 [0, 2^bits-1] 整数区间。
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*
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* @param vertices 顶点坐标列表
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* @param mode 量化模式（决定每分量位数）
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* @return VertexQuantResult
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* @ingroup core
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*/
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VertexQuantResult quantize_vertices(const std::vector<Point3D>& vertices,
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QuantMode mode = QuantMode::Uniform16);
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/**
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* @brief 顶点坐标反量化
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*
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* @param result 量化结果
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* @return 还原的顶点坐标
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* @ingroup core
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*/
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std::vector<Point3D> dequantize_vertices(const VertexQuantResult& result);
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} // namespace vde::core
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