ViewDesignEngine
cf13496ff6
新增功能： - core: 2D Voronoi 图（Delaunay 对偶图） - mesh: Marching Cubes（完整256项三角表 + SDF 辅助函数） - mesh: 离散曲率（Gaussian/Mean, Cotan 公式） - foundation: 二进制序列化（版本化格式，Little-Endian） - python: pybind11 绑定（30+ API 暴露） - marching_cubes.h: SDF 基本体（球/盒）+ 光滑布尔
102 lines
4.0 KiB
C++
102 lines
4.0 KiB
C++
#include "vde/core/voronoi.h"
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#include "vde/mesh/delaunay_2d.h"
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#include <unordered_map>
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#include <algorithm>
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namespace vde::core {
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// Edge key for unordered_map
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struct EdgeKey {
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int a, b;
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EdgeKey(int va, int vb) : a(std::min(va, vb)), b(std::max(va, vb)) {}
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bool operator==(const EdgeKey& o) const { return a == o.a && b == o.b; }
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};
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struct EdgeKeyHash {
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size_t operator()(const EdgeKey& e) const {
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return (static_cast<uint64_t>(e.a) << 32) | static_cast<uint64_t>(e.b);
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}
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};
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std::vector<VoronoiCell> voronoi_2d(const std::vector<Point2D>& points) {
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std::vector<VoronoiCell> cells(points.size());
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for (size_t i = 0; i < points.size(); ++i)
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cells[i].site = points[i];
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if (points.size() < 3) return cells;
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// Compute Delaunay triangulation
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auto dresult = mesh::delaunay_2d(points);
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const auto& verts = dresult.vertices;
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const auto& tris = dresult.triangles;
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// Compute circumcenters for each Delaunay triangle
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std::vector<Point2D> circumcenters;
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for (const auto& tri : tris) {
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Point2D a = verts[tri[0]], b = verts[tri[1]], c = verts[tri[2]];
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double d = 2 * (a.x()*(b.y()-c.y()) + b.x()*(c.y()-a.y()) + c.x()*(a.y()-b.y()));
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if (std::abs(d) < 1e-12) { circumcenters.push_back({0,0}); continue; }
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double ux = ((a.x()*a.x()+a.y()*a.y())*(b.y()-c.y())
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+ (b.x()*b.x()+b.y()*b.y())*(c.y()-a.y())
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+ (c.x()*c.x()+c.y()*c.y())*(a.y()-b.y())) / d;
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double uy = ((a.x()*a.x()+a.y()*a.y())*(c.x()-b.x())
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+ (b.x()*b.x()+b.y()*b.y())*(a.x()-c.x())
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+ (c.x()*c.x()+c.y()*c.y())*(b.x()-a.x())) / d;
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circumcenters.push_back({ux, uy});
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}
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// For each vertex, collect circumcenters of adjacent triangles
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for (size_t i = 0; i < points.size(); ++i) {
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std::vector<Point2D> cell_verts;
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std::unordered_map<EdgeKey, int, EdgeKeyHash> edge_first;
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// Find all triangles containing this vertex
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for (size_t ti = 0; ti < tris.size(); ++ti) {
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const auto& tri = tris[ti];
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for (int j = 0; j < 3; ++j) {
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if (tri[j] == static_cast<int>(i) || tri[(j+1)%3] == static_cast<int>(i)) {
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int v0 = tri[(j+0)%3], v1 = tri[(j+1)%3];
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// Edge v0-v1 connects two circumcenters
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// Find neighboring triangle sharing edge v0-v1
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for (size_t tj = ti + 1; tj < tris.size(); ++tj) {
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const auto& tri2 = tris[tj];
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bool shares[3] = {false, false, false};
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for (int k = 0; k < 3; ++k)
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shares[k] = (tri2[k] == v0 || tri2[k] == v1 ||
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tri2[k] == tri[(j+2)%3]);
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}
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}
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}
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}
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// Simplified: just collect circumcenters of adjacent triangles
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for (size_t ti = 0; ti < tris.size(); ++ti) {
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const auto& tri = tris[ti];
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bool contains = false;
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for (int j = 0; j < 3; ++j)
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if (tri[j] == static_cast<int>(i)) { contains = true; break; }
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if (contains) {
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cells[i].vertices.push_back(circumcenters[ti]);
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}
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}
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// Sort circumcenters angularly around site for proper polygon
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if (cells[i].vertices.size() >= 3) {
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std::sort(cells[i].vertices.begin(), cells[i].vertices.end(),
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[&](const Point2D& a, const Point2D& b) {
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return std::atan2(a.y() - points[i].y(), a.x() - points[i].x()) <
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std::atan2(b.y() - points[i].y(), b.x() - points[i].x());
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});
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// Deduplicate
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auto last = std::unique(cells[i].vertices.begin(), cells[i].vertices.end(),
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[](const Point2D& a, const Point2D& b) {
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return (a-b).norm() < 1e-9;
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});
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cells[i].vertices.erase(last, cells[i].vertices.end());
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}
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}
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return cells;
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}
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} // namespace vde::core
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