ztile.h

/*
    SPDX-FileCopyrightText: 2020 Volker Krause <vkrause@kde.org>
 
    SPDX-License-Identifier: LGPL-2.0-or-later
*/
 
#ifndef OSM_ZTILE_H
#define OSM_ZTILE_H
 
#include <array>
#include <cstdint>
 
namespace OSM {
class BoundingBox;
 
/** Tile in a quad tree made up out of z-order curve positions. */
class ZTile
{
public:
    constexpr ZTile() = default;
    constexpr inline ZTile(uint64_t _z, uint8_t _depth)
        : z(_z)
        , depth(_depth)
    {}
 
    [[nodiscard]] constexpr inline bool operator<(ZTile other) const
    {
        return depth == other.depth ? z < other.z : depth > other.depth;
    }
    [[nodiscard]] constexpr inline bool operator==(ZTile other) const
    {
        return depth == other.depth && z == other.z;
    }
 
    /** tile size in 1e7-th degrees **/
    [[nodiscard]] constexpr inline uint32_t size() const
    {
        return (1ull << depth) - 1;
    }
 
    [[nodiscard]] BoundingBox boundingBox() const;
    [[nodiscard]] bool intersects(BoundingBox bbox) const;
    [[nodiscard]] bool intersects(ZTile other) const;
 
    /** The parent tile in a quad tree. */
    [[nodiscard]] ZTile parent() const;
    /** Split into four sub-tiles on one level below. */
    [[nodiscard]] std::array<ZTile, 4> quadSplit() const;
 
 
    uint64_t z = 0;
    uint8_t depth = 0;
};
 
/** The smallest tile entirely containing the given bounding box. */
ZTile ztileFromBoundingBox(BoundingBox bbox);
 
}
 
#endif // OSM_ZTILE_H