ViewDesignEngine/include/vde/spatial/r_tree.h

#pragma once
#include "vde/spatial/spatial_index.h"
#include "vde/core/aabb.h"
#include <queue>
#include <limits>

namespace vde::spatial {
using core::Point3D;
using core::Vector3D;
using core::Ray3Dd;
using core::Triangle3D;

template <typename T>
struct RTreeNode {
    AABB3D bbox;
    bool is_leaf = true;
    std::vector<size_t> children;      // internal: indices into nodes_
    std::vector<size_t> item_indices;  // leaf: indices into items_
    size_t parent = static_cast<size_t>(-1);
};

template <typename T>
class RTree : public SpatialIndex<T> {
public:
    void build(const std::vector<T>& items) override;
    void insert(const T& item) override;
    bool remove(const T& item) override;
    std::vector<T> query_range(const AABB3D& range) const override;
    std::vector<T> query_knn(const Point3D& point, size_t k) const override;
    std::vector<T> query_ray(const Ray3Dd& ray) const override;
    void clear() override;
    size_t size() const override { return count_; }
    size_t node_count() const { return nodes_.size(); }

private:
    void query_range_recursive(size_t node_idx, const AABB3D& range,
                               std::vector<T>& result) const;

    std::vector<T> items_;
    std::vector<AABB3D> item_bounds_;
    std::vector<RTreeNode<T>> nodes_;
    size_t root_idx_ = 0;
    size_t count_ = 0;
};

}  // namespace vde::spatial